1944 lines
49 KiB
C
1944 lines
49 KiB
C
/*
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* zcache.c
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*
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* Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp.
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* Copyright (c) 2010,2011, Nitin Gupta
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*
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* Zcache provides an in-kernel "host implementation" for transcendent memory
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* ("tmem") and, thus indirectly, for cleancache and frontswap. Zcache uses
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* lzo1x compression to improve density and an embedded allocator called
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* "zbud" which "buddies" two compressed pages semi-optimally in each physical
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* pageframe. Zbud is integrally tied into tmem to allow pageframes to
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* be "reclaimed" efficiently.
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*/
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#include <linux/module.h>
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#include <linux/cpu.h>
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#include <linux/highmem.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/atomic.h>
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#include <linux/math64.h>
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#include <linux/crypto.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/pagemap.h>
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#include <linux/writeback.h>
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#include <linux/cleancache.h>
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#include <linux/frontswap.h>
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#include "tmem.h"
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#include "zcache.h"
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#include "zbud.h"
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#include "ramster.h"
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#include "debug.h"
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#ifdef CONFIG_RAMSTER
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static bool ramster_enabled __read_mostly;
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static int disable_frontswap_selfshrink;
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#else
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#define ramster_enabled false
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#define disable_frontswap_selfshrink 0
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#endif
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#ifndef __PG_WAS_ACTIVE
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static inline bool PageWasActive(struct page *page)
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{
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return true;
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}
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static inline void SetPageWasActive(struct page *page)
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{
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}
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#endif
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#ifdef FRONTSWAP_HAS_EXCLUSIVE_GETS
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static bool frontswap_has_exclusive_gets __read_mostly = true;
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#else
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static bool frontswap_has_exclusive_gets __read_mostly;
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static inline void frontswap_tmem_exclusive_gets(bool b)
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{
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}
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#endif
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/*
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* mark pampd to special value in order that later
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* retrieve will identify zero-filled pages
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*/
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#define ZERO_FILLED 0x2
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/* enable (or fix code) when Seth's patches are accepted upstream */
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#define zcache_writeback_enabled 0
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static bool zcache_enabled __read_mostly;
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static bool disable_cleancache __read_mostly;
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static bool disable_frontswap __read_mostly;
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static bool disable_frontswap_ignore_nonactive __read_mostly;
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static bool disable_cleancache_ignore_nonactive __read_mostly;
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static char *namestr __read_mostly = "zcache";
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#define ZCACHE_GFP_MASK \
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(__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
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/* crypto API for zcache */
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#ifdef CONFIG_ZCACHE_MODULE
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static char *zcache_comp_name = "lzo";
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#else
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#define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME
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static char zcache_comp_name[ZCACHE_COMP_NAME_SZ] __read_mostly;
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#endif
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static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms __read_mostly;
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enum comp_op {
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ZCACHE_COMPOP_COMPRESS,
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ZCACHE_COMPOP_DECOMPRESS
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};
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static inline int zcache_comp_op(enum comp_op op,
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const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen)
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{
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struct crypto_comp *tfm;
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int ret = -1;
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BUG_ON(!zcache_comp_pcpu_tfms);
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tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, get_cpu());
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BUG_ON(!tfm);
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switch (op) {
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case ZCACHE_COMPOP_COMPRESS:
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ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
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break;
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case ZCACHE_COMPOP_DECOMPRESS:
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ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
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break;
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default:
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ret = -EINVAL;
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}
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put_cpu();
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return ret;
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}
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/*
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* policy parameters
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*/
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/*
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* byte count defining poor compression; pages with greater zsize will be
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* rejected
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*/
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static unsigned int zbud_max_zsize __read_mostly = (PAGE_SIZE / 8) * 7;
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/*
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* byte count defining poor *mean* compression; pages with greater zsize
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* will be rejected until sufficient better-compressed pages are accepted
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* driving the mean below this threshold
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*/
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static unsigned int zbud_max_mean_zsize __read_mostly = (PAGE_SIZE / 8) * 5;
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/*
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* for now, used named slabs so can easily track usage; later can
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* either just use kmalloc, or perhaps add a slab-like allocator
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* to more carefully manage total memory utilization
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*/
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static struct kmem_cache *zcache_objnode_cache;
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static struct kmem_cache *zcache_obj_cache;
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static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
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/* Used by debug.c */
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ssize_t zcache_pers_zpages;
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u64 zcache_pers_zbytes;
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ssize_t zcache_eph_pageframes;
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ssize_t zcache_pers_pageframes;
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/* Used by this code. */
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ssize_t zcache_last_active_file_pageframes;
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ssize_t zcache_last_inactive_file_pageframes;
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ssize_t zcache_last_active_anon_pageframes;
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ssize_t zcache_last_inactive_anon_pageframes;
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#ifdef CONFIG_ZCACHE_WRITEBACK
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ssize_t zcache_writtenback_pages;
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ssize_t zcache_outstanding_writeback_pages;
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#endif
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/*
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* zcache core code starts here
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*/
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static struct zcache_client zcache_host;
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static struct zcache_client zcache_clients[MAX_CLIENTS];
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static inline bool is_local_client(struct zcache_client *cli)
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{
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return cli == &zcache_host;
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}
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static struct zcache_client *zcache_get_client_by_id(uint16_t cli_id)
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{
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struct zcache_client *cli = &zcache_host;
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if (cli_id != LOCAL_CLIENT) {
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if (cli_id >= MAX_CLIENTS)
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goto out;
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cli = &zcache_clients[cli_id];
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}
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out:
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return cli;
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}
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/*
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* Tmem operations assume the poolid implies the invoking client.
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* Zcache only has one client (the kernel itself): LOCAL_CLIENT.
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* RAMster has each client numbered by cluster node, and a KVM version
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* of zcache would have one client per guest and each client might
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* have a poolid==N.
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*/
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struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
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{
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struct tmem_pool *pool = NULL;
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struct zcache_client *cli = NULL;
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cli = zcache_get_client_by_id(cli_id);
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if (cli == NULL)
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goto out;
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if (!is_local_client(cli))
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atomic_inc(&cli->refcount);
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if (poolid < MAX_POOLS_PER_CLIENT) {
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pool = cli->tmem_pools[poolid];
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if (pool != NULL)
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atomic_inc(&pool->refcount);
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}
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out:
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return pool;
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}
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void zcache_put_pool(struct tmem_pool *pool)
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{
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struct zcache_client *cli = NULL;
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if (pool == NULL)
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BUG();
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cli = pool->client;
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atomic_dec(&pool->refcount);
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if (!is_local_client(cli))
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atomic_dec(&cli->refcount);
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}
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int zcache_new_client(uint16_t cli_id)
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{
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struct zcache_client *cli;
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int ret = -1;
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cli = zcache_get_client_by_id(cli_id);
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if (cli == NULL)
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goto out;
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if (cli->allocated)
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goto out;
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cli->allocated = 1;
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ret = 0;
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out:
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return ret;
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}
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/*
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* zcache implementation for tmem host ops
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*/
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static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
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{
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struct tmem_objnode *objnode = NULL;
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struct zcache_preload *kp;
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int i;
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kp = &__get_cpu_var(zcache_preloads);
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for (i = 0; i < ARRAY_SIZE(kp->objnodes); i++) {
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objnode = kp->objnodes[i];
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if (objnode != NULL) {
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kp->objnodes[i] = NULL;
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break;
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}
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}
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BUG_ON(objnode == NULL);
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inc_zcache_objnode_count();
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return objnode;
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}
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static void zcache_objnode_free(struct tmem_objnode *objnode,
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struct tmem_pool *pool)
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{
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dec_zcache_objnode_count();
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kmem_cache_free(zcache_objnode_cache, objnode);
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}
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static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
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{
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struct tmem_obj *obj = NULL;
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struct zcache_preload *kp;
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kp = &__get_cpu_var(zcache_preloads);
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obj = kp->obj;
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BUG_ON(obj == NULL);
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kp->obj = NULL;
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inc_zcache_obj_count();
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return obj;
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}
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static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
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{
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dec_zcache_obj_count();
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kmem_cache_free(zcache_obj_cache, obj);
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}
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/*
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* Compressing zero-filled pages will waste memory and introduce
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* serious fragmentation, skip it to avoid overhead.
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*/
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static bool page_is_zero_filled(struct page *p)
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{
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unsigned int pos;
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char *page;
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page = kmap_atomic(p);
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for (pos = 0; pos < PAGE_SIZE / sizeof(*page); pos++) {
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if (page[pos]) {
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kunmap_atomic(page);
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return false;
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}
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}
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kunmap_atomic(page);
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return true;
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}
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static void handle_zero_filled_page(void *p)
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{
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void *user_mem;
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struct page *page = (struct page *)p;
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user_mem = kmap_atomic(page);
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memset(user_mem, 0, PAGE_SIZE);
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kunmap_atomic(user_mem);
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flush_dcache_page(page);
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}
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static struct tmem_hostops zcache_hostops = {
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.obj_alloc = zcache_obj_alloc,
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.obj_free = zcache_obj_free,
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.objnode_alloc = zcache_objnode_alloc,
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.objnode_free = zcache_objnode_free,
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};
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static struct page *zcache_alloc_page(void)
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{
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struct page *page = alloc_page(ZCACHE_GFP_MASK);
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if (page != NULL)
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inc_zcache_pageframes_alloced();
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return page;
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}
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static void zcache_free_page(struct page *page)
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{
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long curr_pageframes;
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static long max_pageframes, min_pageframes;
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if (page == NULL)
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BUG();
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__free_page(page);
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inc_zcache_pageframes_freed();
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curr_pageframes = curr_pageframes_count();
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if (curr_pageframes > max_pageframes)
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max_pageframes = curr_pageframes;
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if (curr_pageframes < min_pageframes)
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min_pageframes = curr_pageframes;
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#ifdef CONFIG_ZCACHE_DEBUG
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if (curr_pageframes > 2L || curr_pageframes < -2L) {
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/* pr_info here */
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}
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#endif
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}
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/*
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* zcache implementations for PAM page descriptor ops
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*/
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/* forward reference */
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static void zcache_compress(struct page *from,
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void **out_va, unsigned *out_len);
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static struct page *zcache_evict_eph_pageframe(void);
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static void *zcache_pampd_eph_create(char *data, size_t size, bool raw,
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struct tmem_handle *th)
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{
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void *pampd = NULL, *cdata = data;
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unsigned clen = size;
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bool zero_filled = false;
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struct page *page = (struct page *)(data), *newpage;
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if (page_is_zero_filled(page)) {
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clen = 0;
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zero_filled = true;
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inc_zcache_zero_filled_pages();
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goto got_pampd;
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}
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if (!raw) {
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zcache_compress(page, &cdata, &clen);
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if (clen > zbud_max_buddy_size()) {
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inc_zcache_compress_poor();
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goto out;
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}
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} else {
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BUG_ON(clen > zbud_max_buddy_size());
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}
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/* look for space via an existing match first */
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pampd = (void *)zbud_match_prep(th, true, cdata, clen);
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if (pampd != NULL)
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goto got_pampd;
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/* no match, now we need to find (or free up) a full page */
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newpage = zcache_alloc_page();
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if (newpage != NULL)
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goto create_in_new_page;
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inc_zcache_failed_getfreepages();
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/* can't allocate a page, evict an ephemeral page via LRU */
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newpage = zcache_evict_eph_pageframe();
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if (newpage == NULL) {
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inc_zcache_eph_ate_tail_failed();
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goto out;
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}
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inc_zcache_eph_ate_tail();
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create_in_new_page:
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pampd = (void *)zbud_create_prep(th, true, cdata, clen, newpage);
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BUG_ON(pampd == NULL);
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inc_zcache_eph_pageframes();
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got_pampd:
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inc_zcache_eph_zbytes(clen);
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inc_zcache_eph_zpages();
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if (ramster_enabled && raw && !zero_filled)
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ramster_count_foreign_pages(true, 1);
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if (zero_filled)
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pampd = (void *)ZERO_FILLED;
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out:
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return pampd;
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}
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static void *zcache_pampd_pers_create(char *data, size_t size, bool raw,
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struct tmem_handle *th)
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{
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void *pampd = NULL, *cdata = data;
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unsigned clen = size;
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bool zero_filled = false;
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struct page *page = (struct page *)(data), *newpage;
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unsigned long zbud_mean_zsize;
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unsigned long curr_pers_zpages, total_zsize;
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if (data == NULL) {
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BUG_ON(!ramster_enabled);
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goto create_pampd;
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}
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if (page_is_zero_filled(page)) {
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clen = 0;
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zero_filled = true;
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inc_zcache_zero_filled_pages();
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goto got_pampd;
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}
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curr_pers_zpages = zcache_pers_zpages;
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/* FIXME CONFIG_RAMSTER... subtract atomic remote_pers_pages here? */
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if (!raw)
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zcache_compress(page, &cdata, &clen);
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/* reject if compression is too poor */
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if (clen > zbud_max_zsize) {
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inc_zcache_compress_poor();
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goto out;
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}
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/* reject if mean compression is too poor */
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if ((clen > zbud_max_mean_zsize) && (curr_pers_zpages > 0)) {
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total_zsize = zcache_pers_zbytes;
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if ((long)total_zsize < 0)
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total_zsize = 0;
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zbud_mean_zsize = div_u64(total_zsize,
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curr_pers_zpages);
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if (zbud_mean_zsize > zbud_max_mean_zsize) {
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inc_zcache_mean_compress_poor();
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goto out;
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}
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}
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create_pampd:
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/* look for space via an existing match first */
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pampd = (void *)zbud_match_prep(th, false, cdata, clen);
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if (pampd != NULL)
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goto got_pampd;
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/* no match, now we need to find (or free up) a full page */
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newpage = zcache_alloc_page();
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if (newpage != NULL)
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goto create_in_new_page;
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/*
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* FIXME do the following only if eph is oversized?
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* if (zcache_eph_pageframes >
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* (global_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE) +
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* global_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE)))
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*/
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inc_zcache_failed_getfreepages();
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/* can't allocate a page, evict an ephemeral page via LRU */
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newpage = zcache_evict_eph_pageframe();
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if (newpage == NULL) {
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inc_zcache_pers_ate_eph_failed();
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goto out;
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}
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inc_zcache_pers_ate_eph();
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create_in_new_page:
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pampd = (void *)zbud_create_prep(th, false, cdata, clen, newpage);
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BUG_ON(pampd == NULL);
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inc_zcache_pers_pageframes();
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got_pampd:
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inc_zcache_pers_zpages();
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inc_zcache_pers_zbytes(clen);
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if (ramster_enabled && raw && !zero_filled)
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ramster_count_foreign_pages(false, 1);
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if (zero_filled)
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pampd = (void *)ZERO_FILLED;
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out:
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return pampd;
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}
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/*
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* This is called directly from zcache_put_page to pre-allocate space
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* to store a zpage.
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*/
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void *zcache_pampd_create(char *data, unsigned int size, bool raw,
|
|
int eph, struct tmem_handle *th)
|
|
{
|
|
void *pampd = NULL;
|
|
struct zcache_preload *kp;
|
|
struct tmem_objnode *objnode;
|
|
struct tmem_obj *obj;
|
|
int i;
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
/* pre-allocate per-cpu metadata */
|
|
BUG_ON(zcache_objnode_cache == NULL);
|
|
BUG_ON(zcache_obj_cache == NULL);
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
for (i = 0; i < ARRAY_SIZE(kp->objnodes); i++) {
|
|
objnode = kp->objnodes[i];
|
|
if (objnode == NULL) {
|
|
objnode = kmem_cache_alloc(zcache_objnode_cache,
|
|
ZCACHE_GFP_MASK);
|
|
if (unlikely(objnode == NULL)) {
|
|
inc_zcache_failed_alloc();
|
|
goto out;
|
|
}
|
|
kp->objnodes[i] = objnode;
|
|
}
|
|
}
|
|
if (kp->obj == NULL) {
|
|
obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
|
|
kp->obj = obj;
|
|
}
|
|
if (unlikely(kp->obj == NULL)) {
|
|
inc_zcache_failed_alloc();
|
|
goto out;
|
|
}
|
|
/*
|
|
* ok, have all the metadata pre-allocated, now do the data
|
|
* but since how we allocate the data is dependent on ephemeral
|
|
* or persistent, we split the call here to different sub-functions
|
|
*/
|
|
if (eph)
|
|
pampd = zcache_pampd_eph_create(data, size, raw, th);
|
|
else
|
|
pampd = zcache_pampd_pers_create(data, size, raw, th);
|
|
out:
|
|
return pampd;
|
|
}
|
|
|
|
/*
|
|
* This is a pamops called via tmem_put and is necessary to "finish"
|
|
* a pampd creation.
|
|
*/
|
|
void zcache_pampd_create_finish(void *pampd, bool eph)
|
|
{
|
|
if (pampd != (void *)ZERO_FILLED)
|
|
zbud_create_finish((struct zbudref *)pampd, eph);
|
|
}
|
|
|
|
/*
|
|
* This is passed as a function parameter to zbud_decompress so that
|
|
* zbud need not be familiar with the details of crypto. It assumes that
|
|
* the bytes from_va and to_va through from_va+size-1 and to_va+size-1 are
|
|
* kmapped. It must be successful, else there is a logic bug somewhere.
|
|
*/
|
|
static void zcache_decompress(char *from_va, unsigned int size, char *to_va)
|
|
{
|
|
int ret;
|
|
unsigned int outlen = PAGE_SIZE;
|
|
|
|
ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size,
|
|
to_va, &outlen);
|
|
BUG_ON(ret);
|
|
BUG_ON(outlen != PAGE_SIZE);
|
|
}
|
|
|
|
/*
|
|
* Decompress from the kernel va to a pageframe
|
|
*/
|
|
void zcache_decompress_to_page(char *from_va, unsigned int size,
|
|
struct page *to_page)
|
|
{
|
|
char *to_va = kmap_atomic(to_page);
|
|
zcache_decompress(from_va, size, to_va);
|
|
kunmap_atomic(to_va);
|
|
}
|
|
|
|
/*
|
|
* fill the pageframe corresponding to the struct page with the data
|
|
* from the passed pampd
|
|
*/
|
|
static int zcache_pampd_get_data(char *data, size_t *sizep, bool raw,
|
|
void *pampd, struct tmem_pool *pool,
|
|
struct tmem_oid *oid, uint32_t index)
|
|
{
|
|
int ret;
|
|
bool eph = !is_persistent(pool);
|
|
|
|
BUG_ON(preemptible());
|
|
BUG_ON(eph); /* fix later if shared pools get implemented */
|
|
BUG_ON(pampd_is_remote(pampd));
|
|
|
|
if (pampd == (void *)ZERO_FILLED) {
|
|
handle_zero_filled_page(data);
|
|
if (!raw)
|
|
*sizep = PAGE_SIZE;
|
|
return 0;
|
|
}
|
|
|
|
if (raw)
|
|
ret = zbud_copy_from_zbud(data, (struct zbudref *)pampd,
|
|
sizep, eph);
|
|
else {
|
|
ret = zbud_decompress((struct page *)(data),
|
|
(struct zbudref *)pampd, false,
|
|
zcache_decompress);
|
|
*sizep = PAGE_SIZE;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* fill the pageframe corresponding to the struct page with the data
|
|
* from the passed pampd
|
|
*/
|
|
static int zcache_pampd_get_data_and_free(char *data, size_t *sizep, bool raw,
|
|
void *pampd, struct tmem_pool *pool,
|
|
struct tmem_oid *oid, uint32_t index)
|
|
{
|
|
int ret = 0;
|
|
bool eph = !is_persistent(pool), zero_filled = false;
|
|
struct page *page = NULL;
|
|
unsigned int zsize, zpages;
|
|
|
|
BUG_ON(preemptible());
|
|
BUG_ON(pampd_is_remote(pampd));
|
|
|
|
if (pampd == (void *)ZERO_FILLED) {
|
|
handle_zero_filled_page(data);
|
|
zero_filled = true;
|
|
zsize = 0;
|
|
zpages = 1;
|
|
if (!raw)
|
|
*sizep = PAGE_SIZE;
|
|
dec_zcache_zero_filled_pages();
|
|
goto zero_fill;
|
|
}
|
|
|
|
if (raw)
|
|
ret = zbud_copy_from_zbud(data, (struct zbudref *)pampd,
|
|
sizep, eph);
|
|
else {
|
|
ret = zbud_decompress((struct page *)(data),
|
|
(struct zbudref *)pampd, eph,
|
|
zcache_decompress);
|
|
*sizep = PAGE_SIZE;
|
|
}
|
|
page = zbud_free_and_delist((struct zbudref *)pampd, eph,
|
|
&zsize, &zpages);
|
|
zero_fill:
|
|
if (eph) {
|
|
if (page)
|
|
dec_zcache_eph_pageframes();
|
|
dec_zcache_eph_zpages(zpages);
|
|
dec_zcache_eph_zbytes(zsize);
|
|
} else {
|
|
if (page)
|
|
dec_zcache_pers_pageframes();
|
|
dec_zcache_pers_zpages(zpages);
|
|
dec_zcache_pers_zbytes(zsize);
|
|
}
|
|
if (!is_local_client(pool->client) && !zero_filled)
|
|
ramster_count_foreign_pages(eph, -1);
|
|
if (page && !zero_filled)
|
|
zcache_free_page(page);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* free the pampd and remove it from any zcache lists
|
|
* pampd must no longer be pointed to from any tmem data structures!
|
|
*/
|
|
static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
|
|
struct tmem_oid *oid, uint32_t index, bool acct)
|
|
{
|
|
struct page *page = NULL;
|
|
unsigned int zsize, zpages;
|
|
bool zero_filled = false;
|
|
|
|
BUG_ON(preemptible());
|
|
|
|
if (pampd == (void *)ZERO_FILLED) {
|
|
zero_filled = true;
|
|
zsize = 0;
|
|
zpages = 1;
|
|
dec_zcache_zero_filled_pages();
|
|
}
|
|
|
|
if (pampd_is_remote(pampd) && !zero_filled) {
|
|
BUG_ON(!ramster_enabled);
|
|
pampd = ramster_pampd_free(pampd, pool, oid, index, acct);
|
|
if (pampd == NULL)
|
|
return;
|
|
}
|
|
if (is_ephemeral(pool)) {
|
|
if (!zero_filled)
|
|
page = zbud_free_and_delist((struct zbudref *)pampd,
|
|
true, &zsize, &zpages);
|
|
if (page)
|
|
dec_zcache_eph_pageframes();
|
|
dec_zcache_eph_zpages(zpages);
|
|
dec_zcache_eph_zbytes(zsize);
|
|
/* FIXME CONFIG_RAMSTER... check acct parameter? */
|
|
} else {
|
|
if (!zero_filled)
|
|
page = zbud_free_and_delist((struct zbudref *)pampd,
|
|
false, &zsize, &zpages);
|
|
if (page)
|
|
dec_zcache_pers_pageframes();
|
|
dec_zcache_pers_zpages(zpages);
|
|
dec_zcache_pers_zbytes(zsize);
|
|
}
|
|
if (!is_local_client(pool->client) && !zero_filled)
|
|
ramster_count_foreign_pages(is_ephemeral(pool), -1);
|
|
if (page && !zero_filled)
|
|
zcache_free_page(page);
|
|
}
|
|
|
|
static struct tmem_pamops zcache_pamops = {
|
|
.create_finish = zcache_pampd_create_finish,
|
|
.get_data = zcache_pampd_get_data,
|
|
.get_data_and_free = zcache_pampd_get_data_and_free,
|
|
.free = zcache_pampd_free,
|
|
};
|
|
|
|
/*
|
|
* zcache compression/decompression and related per-cpu stuff
|
|
*/
|
|
|
|
static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
|
|
#define ZCACHE_DSTMEM_ORDER 1
|
|
|
|
static void zcache_compress(struct page *from, void **out_va, unsigned *out_len)
|
|
{
|
|
int ret;
|
|
unsigned char *dmem = __get_cpu_var(zcache_dstmem);
|
|
char *from_va;
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
/* no buffer or no compressor so can't compress */
|
|
BUG_ON(dmem == NULL);
|
|
*out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER;
|
|
from_va = kmap_atomic(from);
|
|
mb();
|
|
ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem,
|
|
out_len);
|
|
BUG_ON(ret);
|
|
*out_va = dmem;
|
|
kunmap_atomic(from_va);
|
|
}
|
|
|
|
static int zcache_comp_cpu_up(int cpu)
|
|
{
|
|
struct crypto_comp *tfm;
|
|
|
|
tfm = crypto_alloc_comp(zcache_comp_name, 0, 0);
|
|
if (IS_ERR(tfm))
|
|
return NOTIFY_BAD;
|
|
*per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = tfm;
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static void zcache_comp_cpu_down(int cpu)
|
|
{
|
|
struct crypto_comp *tfm;
|
|
|
|
tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu);
|
|
crypto_free_comp(tfm);
|
|
*per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = NULL;
|
|
}
|
|
|
|
static int zcache_cpu_notifier(struct notifier_block *nb,
|
|
unsigned long action, void *pcpu)
|
|
{
|
|
int ret, i, cpu = (long)pcpu;
|
|
struct zcache_preload *kp;
|
|
|
|
switch (action) {
|
|
case CPU_UP_PREPARE:
|
|
ret = zcache_comp_cpu_up(cpu);
|
|
if (ret != NOTIFY_OK) {
|
|
pr_err("%s: can't allocate compressor xform\n",
|
|
namestr);
|
|
return ret;
|
|
}
|
|
per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
|
|
GFP_KERNEL | __GFP_REPEAT, ZCACHE_DSTMEM_ORDER);
|
|
if (ramster_enabled)
|
|
ramster_cpu_up(cpu);
|
|
break;
|
|
case CPU_DEAD:
|
|
case CPU_UP_CANCELED:
|
|
zcache_comp_cpu_down(cpu);
|
|
free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
|
|
ZCACHE_DSTMEM_ORDER);
|
|
per_cpu(zcache_dstmem, cpu) = NULL;
|
|
kp = &per_cpu(zcache_preloads, cpu);
|
|
for (i = 0; i < ARRAY_SIZE(kp->objnodes); i++) {
|
|
if (kp->objnodes[i])
|
|
kmem_cache_free(zcache_objnode_cache,
|
|
kp->objnodes[i]);
|
|
}
|
|
if (kp->obj) {
|
|
kmem_cache_free(zcache_obj_cache, kp->obj);
|
|
kp->obj = NULL;
|
|
}
|
|
if (ramster_enabled)
|
|
ramster_cpu_down(cpu);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block zcache_cpu_notifier_block = {
|
|
.notifier_call = zcache_cpu_notifier
|
|
};
|
|
|
|
/*
|
|
* The following code interacts with the zbud eviction and zbud
|
|
* zombify code to access LRU pages
|
|
*/
|
|
|
|
static struct page *zcache_evict_eph_pageframe(void)
|
|
{
|
|
struct page *page;
|
|
unsigned int zsize = 0, zpages = 0;
|
|
|
|
page = zbud_evict_pageframe_lru(&zsize, &zpages);
|
|
if (page == NULL)
|
|
goto out;
|
|
dec_zcache_eph_zbytes(zsize);
|
|
dec_zcache_eph_zpages(zpages);
|
|
inc_zcache_evicted_eph_zpages(zpages);
|
|
dec_zcache_eph_pageframes();
|
|
inc_zcache_evicted_eph_pageframes();
|
|
out:
|
|
return page;
|
|
}
|
|
|
|
#ifdef CONFIG_ZCACHE_WRITEBACK
|
|
|
|
static atomic_t zcache_outstanding_writeback_pages_atomic = ATOMIC_INIT(0);
|
|
|
|
static inline void inc_zcache_outstanding_writeback_pages(void)
|
|
{
|
|
zcache_outstanding_writeback_pages =
|
|
atomic_inc_return(&zcache_outstanding_writeback_pages_atomic);
|
|
}
|
|
static inline void dec_zcache_outstanding_writeback_pages(void)
|
|
{
|
|
zcache_outstanding_writeback_pages =
|
|
atomic_dec_return(&zcache_outstanding_writeback_pages_atomic);
|
|
};
|
|
static void unswiz(struct tmem_oid oid, u32 index,
|
|
unsigned *type, pgoff_t *offset);
|
|
|
|
/*
|
|
* Choose an LRU persistent pageframe and attempt to write it back to
|
|
* the backing swap disk by calling frontswap_writeback on both zpages.
|
|
*
|
|
* This is work-in-progress.
|
|
*/
|
|
|
|
static void zcache_end_swap_write(struct bio *bio, int err)
|
|
{
|
|
end_swap_bio_write(bio, err);
|
|
dec_zcache_outstanding_writeback_pages();
|
|
zcache_writtenback_pages++;
|
|
}
|
|
|
|
/*
|
|
* zcache_get_swap_cache_page
|
|
*
|
|
* This is an adaption of read_swap_cache_async()
|
|
*
|
|
* If success, page is returned in retpage
|
|
* Returns 0 if page was already in the swap cache, page is not locked
|
|
* Returns 1 if the new page needs to be populated, page is locked
|
|
*/
|
|
static int zcache_get_swap_cache_page(int type, pgoff_t offset,
|
|
struct page *new_page)
|
|
{
|
|
struct page *found_page;
|
|
swp_entry_t entry = swp_entry(type, offset);
|
|
int err;
|
|
|
|
BUG_ON(new_page == NULL);
|
|
do {
|
|
/*
|
|
* First check the swap cache. Since this is normally
|
|
* called after lookup_swap_cache() failed, re-calling
|
|
* that would confuse statistics.
|
|
*/
|
|
found_page = find_get_page(&swapper_space, entry.val);
|
|
if (found_page)
|
|
return 0;
|
|
|
|
/*
|
|
* call radix_tree_preload() while we can wait.
|
|
*/
|
|
err = radix_tree_preload(GFP_KERNEL);
|
|
if (err)
|
|
break;
|
|
|
|
/*
|
|
* Swap entry may have been freed since our caller observed it.
|
|
*/
|
|
err = swapcache_prepare(entry);
|
|
if (err == -EEXIST) { /* seems racy */
|
|
radix_tree_preload_end();
|
|
continue;
|
|
}
|
|
if (err) { /* swp entry is obsolete ? */
|
|
radix_tree_preload_end();
|
|
break;
|
|
}
|
|
|
|
/* May fail (-ENOMEM) if radix-tree node allocation failed. */
|
|
__set_page_locked(new_page);
|
|
SetPageSwapBacked(new_page);
|
|
err = __add_to_swap_cache(new_page, entry);
|
|
if (likely(!err)) {
|
|
radix_tree_preload_end();
|
|
lru_cache_add_anon(new_page);
|
|
return 1;
|
|
}
|
|
radix_tree_preload_end();
|
|
ClearPageSwapBacked(new_page);
|
|
__clear_page_locked(new_page);
|
|
/*
|
|
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
|
|
* clear SWAP_HAS_CACHE flag.
|
|
*/
|
|
swapcache_free(entry, NULL);
|
|
/* FIXME: is it possible to get here without err==-ENOMEM?
|
|
* If not, we can dispense with the do loop, use goto retry */
|
|
} while (err != -ENOMEM);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Given a frontswap zpage in zcache (identified by type/offset) and
|
|
* an empty page, put the page into the swap cache, use frontswap
|
|
* to get the page from zcache into the empty page, then give it
|
|
* to the swap subsystem to send to disk (carefully avoiding the
|
|
* possibility that frontswap might snatch it back).
|
|
* Returns < 0 if error, 0 if successful, and 1 if successful but
|
|
* the newpage passed in not needed and should be freed.
|
|
*/
|
|
static int zcache_frontswap_writeback_zpage(int type, pgoff_t offset,
|
|
struct page *newpage)
|
|
{
|
|
struct page *page = newpage;
|
|
int ret;
|
|
struct writeback_control wbc = {
|
|
.sync_mode = WB_SYNC_NONE,
|
|
};
|
|
|
|
ret = zcache_get_swap_cache_page(type, offset, page);
|
|
if (ret < 0)
|
|
return ret;
|
|
else if (ret == 0) {
|
|
/* more uptodate page is already in swapcache */
|
|
__frontswap_invalidate_page(type, offset);
|
|
return 1;
|
|
}
|
|
|
|
BUG_ON(!frontswap_has_exclusive_gets); /* load must also invalidate */
|
|
/* FIXME: how is it possible to get here when page is unlocked? */
|
|
__frontswap_load(page);
|
|
SetPageUptodate(page); /* above does SetPageDirty, is that enough? */
|
|
|
|
/* start writeback */
|
|
SetPageReclaim(page);
|
|
/*
|
|
* Return value is ignored here because it doesn't change anything
|
|
* for us. Page is returned unlocked.
|
|
*/
|
|
(void)__swap_writepage(page, &wbc, zcache_end_swap_write);
|
|
page_cache_release(page);
|
|
inc_zcache_outstanding_writeback_pages();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* The following is still a magic number... we want to allow forward progress
|
|
* for writeback because it clears out needed RAM when under pressure, but
|
|
* we don't want to allow writeback to absorb and queue too many GFP_KERNEL
|
|
* pages if the swap device is very slow.
|
|
*/
|
|
#define ZCACHE_MAX_OUTSTANDING_WRITEBACK_PAGES 6400
|
|
|
|
/*
|
|
* Try to allocate two free pages, first using a non-aggressive alloc,
|
|
* then by evicting zcache ephemeral (clean pagecache) pages, and last
|
|
* by aggressive GFP_KERNEL alloc. We allow zbud to choose a pageframe
|
|
* consisting of 1-2 zbuds/zpages, then call the writeback_zpage helper
|
|
* function above for each.
|
|
*/
|
|
static int zcache_frontswap_writeback(void)
|
|
{
|
|
struct tmem_handle th[2];
|
|
int ret = 0;
|
|
int nzbuds, writeback_ret;
|
|
unsigned type;
|
|
struct page *znewpage1 = NULL, *znewpage2 = NULL;
|
|
struct page *evictpage1 = NULL, *evictpage2 = NULL;
|
|
struct page *newpage1 = NULL, *newpage2 = NULL;
|
|
struct page *page1 = NULL, *page2 = NULL;
|
|
pgoff_t offset;
|
|
|
|
znewpage1 = alloc_page(ZCACHE_GFP_MASK);
|
|
znewpage2 = alloc_page(ZCACHE_GFP_MASK);
|
|
if (znewpage1 == NULL)
|
|
evictpage1 = zcache_evict_eph_pageframe();
|
|
if (znewpage2 == NULL)
|
|
evictpage2 = zcache_evict_eph_pageframe();
|
|
|
|
if ((evictpage1 == NULL || evictpage2 == NULL) &&
|
|
atomic_read(&zcache_outstanding_writeback_pages_atomic) >
|
|
ZCACHE_MAX_OUTSTANDING_WRITEBACK_PAGES) {
|
|
goto free_and_out;
|
|
}
|
|
if (znewpage1 == NULL && evictpage1 == NULL)
|
|
newpage1 = alloc_page(GFP_KERNEL);
|
|
if (znewpage2 == NULL && evictpage2 == NULL)
|
|
newpage2 = alloc_page(GFP_KERNEL);
|
|
if (newpage1 == NULL || newpage2 == NULL)
|
|
goto free_and_out;
|
|
|
|
/* ok, we have two pageframes pre-allocated, get a pair of zbuds */
|
|
nzbuds = zbud_make_zombie_lru(&th[0], NULL, NULL, false);
|
|
if (nzbuds == 0) {
|
|
ret = -ENOENT;
|
|
goto free_and_out;
|
|
}
|
|
|
|
/* process the first zbud */
|
|
unswiz(th[0].oid, th[0].index, &type, &offset);
|
|
page1 = (znewpage1 != NULL) ? znewpage1 :
|
|
((newpage1 != NULL) ? newpage1 : evictpage1);
|
|
writeback_ret = zcache_frontswap_writeback_zpage(type, offset, page1);
|
|
if (writeback_ret < 0) {
|
|
ret = -ENOMEM;
|
|
goto free_and_out;
|
|
}
|
|
if (evictpage1 != NULL)
|
|
zcache_pageframes_freed =
|
|
atomic_inc_return(&zcache_pageframes_freed_atomic);
|
|
if (writeback_ret == 0) {
|
|
/* zcache_get_swap_cache_page will free, don't double free */
|
|
znewpage1 = NULL;
|
|
newpage1 = NULL;
|
|
evictpage1 = NULL;
|
|
}
|
|
if (nzbuds < 2)
|
|
goto free_and_out;
|
|
|
|
/* if there is a second zbud, process it */
|
|
unswiz(th[1].oid, th[1].index, &type, &offset);
|
|
page2 = (znewpage2 != NULL) ? znewpage2 :
|
|
((newpage2 != NULL) ? newpage2 : evictpage2);
|
|
writeback_ret = zcache_frontswap_writeback_zpage(type, offset, page2);
|
|
if (writeback_ret < 0) {
|
|
ret = -ENOMEM;
|
|
goto free_and_out;
|
|
}
|
|
if (evictpage2 != NULL)
|
|
zcache_pageframes_freed =
|
|
atomic_inc_return(&zcache_pageframes_freed_atomic);
|
|
if (writeback_ret == 0) {
|
|
znewpage2 = NULL;
|
|
newpage2 = NULL;
|
|
evictpage2 = NULL;
|
|
}
|
|
|
|
free_and_out:
|
|
if (znewpage1 != NULL)
|
|
page_cache_release(znewpage1);
|
|
if (znewpage2 != NULL)
|
|
page_cache_release(znewpage2);
|
|
if (newpage1 != NULL)
|
|
page_cache_release(newpage1);
|
|
if (newpage2 != NULL)
|
|
page_cache_release(newpage2);
|
|
if (evictpage1 != NULL)
|
|
zcache_free_page(evictpage1);
|
|
if (evictpage2 != NULL)
|
|
zcache_free_page(evictpage2);
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_ZCACHE_WRITEBACK */
|
|
|
|
/*
|
|
* When zcache is disabled ("frozen"), pools can be created and destroyed,
|
|
* but all puts (and thus all other operations that require memory allocation)
|
|
* must fail. If zcache is unfrozen, accepts puts, then frozen again,
|
|
* data consistency requires all puts while frozen to be converted into
|
|
* flushes.
|
|
*/
|
|
static bool zcache_freeze;
|
|
|
|
/*
|
|
* This zcache shrinker interface reduces the number of ephemeral pageframes
|
|
* used by zcache to approximately the same as the total number of LRU_FILE
|
|
* pageframes in use, and now also reduces the number of persistent pageframes
|
|
* used by zcache to approximately the same as the total number of LRU_ANON
|
|
* pageframes in use. FIXME POLICY: Probably the writeback should only occur
|
|
* if the eviction doesn't free enough pages.
|
|
*/
|
|
static int shrink_zcache_memory(struct shrinker *shrink,
|
|
struct shrink_control *sc)
|
|
{
|
|
static bool in_progress;
|
|
int ret = -1;
|
|
int nr = sc->nr_to_scan;
|
|
int nr_evict = 0;
|
|
int nr_writeback = 0;
|
|
struct page *page;
|
|
int file_pageframes_inuse, anon_pageframes_inuse;
|
|
|
|
if (nr <= 0)
|
|
goto skip_evict;
|
|
|
|
/* don't allow more than one eviction thread at a time */
|
|
if (in_progress)
|
|
goto skip_evict;
|
|
|
|
in_progress = true;
|
|
|
|
/* we are going to ignore nr, and target a different value */
|
|
zcache_last_active_file_pageframes =
|
|
global_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE);
|
|
zcache_last_inactive_file_pageframes =
|
|
global_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE);
|
|
file_pageframes_inuse = zcache_last_active_file_pageframes +
|
|
zcache_last_inactive_file_pageframes;
|
|
if (zcache_eph_pageframes > file_pageframes_inuse)
|
|
nr_evict = zcache_eph_pageframes - file_pageframes_inuse;
|
|
else
|
|
nr_evict = 0;
|
|
while (nr_evict-- > 0) {
|
|
page = zcache_evict_eph_pageframe();
|
|
if (page == NULL)
|
|
break;
|
|
zcache_free_page(page);
|
|
}
|
|
|
|
zcache_last_active_anon_pageframes =
|
|
global_page_state(NR_LRU_BASE + LRU_ACTIVE_ANON);
|
|
zcache_last_inactive_anon_pageframes =
|
|
global_page_state(NR_LRU_BASE + LRU_INACTIVE_ANON);
|
|
anon_pageframes_inuse = zcache_last_active_anon_pageframes +
|
|
zcache_last_inactive_anon_pageframes;
|
|
if (zcache_pers_pageframes > anon_pageframes_inuse)
|
|
nr_writeback = zcache_pers_pageframes - anon_pageframes_inuse;
|
|
else
|
|
nr_writeback = 0;
|
|
while (nr_writeback-- > 0) {
|
|
#ifdef CONFIG_ZCACHE_WRITEBACK
|
|
int writeback_ret;
|
|
writeback_ret = zcache_frontswap_writeback();
|
|
if (writeback_ret == -ENOMEM)
|
|
#endif
|
|
break;
|
|
}
|
|
in_progress = false;
|
|
|
|
skip_evict:
|
|
/* resample: has changed, but maybe not all the way yet */
|
|
zcache_last_active_file_pageframes =
|
|
global_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE);
|
|
zcache_last_inactive_file_pageframes =
|
|
global_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE);
|
|
ret = zcache_eph_pageframes - zcache_last_active_file_pageframes +
|
|
zcache_last_inactive_file_pageframes;
|
|
if (ret < 0)
|
|
ret = 0;
|
|
return ret;
|
|
}
|
|
|
|
static struct shrinker zcache_shrinker = {
|
|
.shrink = shrink_zcache_memory,
|
|
.seeks = DEFAULT_SEEKS,
|
|
};
|
|
|
|
/*
|
|
* zcache shims between cleancache/frontswap ops and tmem
|
|
*/
|
|
|
|
/* FIXME rename these core routines to zcache_tmemput etc? */
|
|
int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
|
|
uint32_t index, void *page,
|
|
unsigned int size, bool raw, int ephemeral)
|
|
{
|
|
struct tmem_pool *pool;
|
|
struct tmem_handle th;
|
|
int ret = -1;
|
|
void *pampd = NULL;
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (unlikely(pool == NULL))
|
|
goto out;
|
|
if (!zcache_freeze) {
|
|
ret = 0;
|
|
th.client_id = cli_id;
|
|
th.pool_id = pool_id;
|
|
th.oid = *oidp;
|
|
th.index = index;
|
|
pampd = zcache_pampd_create((char *)page, size, raw,
|
|
ephemeral, &th);
|
|
if (pampd == NULL) {
|
|
ret = -ENOMEM;
|
|
if (ephemeral)
|
|
inc_zcache_failed_eph_puts();
|
|
else
|
|
inc_zcache_failed_pers_puts();
|
|
} else {
|
|
if (ramster_enabled)
|
|
ramster_do_preload_flnode(pool);
|
|
ret = tmem_put(pool, oidp, index, 0, pampd);
|
|
if (ret < 0)
|
|
BUG();
|
|
}
|
|
zcache_put_pool(pool);
|
|
} else {
|
|
inc_zcache_put_to_flush();
|
|
if (ramster_enabled)
|
|
ramster_do_preload_flnode(pool);
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
/* the put fails whether the flush succeeds or not */
|
|
(void)tmem_flush_page(pool, oidp, index);
|
|
zcache_put_pool(pool);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
|
|
uint32_t index, void *page,
|
|
size_t *sizep, bool raw, int get_and_free)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
bool eph;
|
|
|
|
if (!raw) {
|
|
BUG_ON(irqs_disabled());
|
|
BUG_ON(in_softirq());
|
|
}
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
eph = is_ephemeral(pool);
|
|
if (likely(pool != NULL)) {
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
ret = tmem_get(pool, oidp, index, (char *)(page),
|
|
sizep, raw, get_and_free);
|
|
zcache_put_pool(pool);
|
|
}
|
|
WARN_ONCE((!is_ephemeral(pool) && (ret != 0)),
|
|
"zcache_get fails on persistent pool, "
|
|
"bad things are very likely to happen soon\n");
|
|
#ifdef RAMSTER_TESTING
|
|
if (ret != 0 && ret != -1 && !(ret == -EINVAL && is_ephemeral(pool)))
|
|
pr_err("TESTING zcache_get tmem_get returns ret=%d\n", ret);
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
int zcache_flush_page(int cli_id, int pool_id,
|
|
struct tmem_oid *oidp, uint32_t index)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
inc_zcache_flush_total();
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (ramster_enabled)
|
|
ramster_do_preload_flnode(pool);
|
|
if (likely(pool != NULL)) {
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
ret = tmem_flush_page(pool, oidp, index);
|
|
zcache_put_pool(pool);
|
|
}
|
|
if (ret >= 0)
|
|
inc_zcache_flush_found();
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
int zcache_flush_object(int cli_id, int pool_id,
|
|
struct tmem_oid *oidp)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
inc_zcache_flobj_total();
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (ramster_enabled)
|
|
ramster_do_preload_flnode(pool);
|
|
if (likely(pool != NULL)) {
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
ret = tmem_flush_object(pool, oidp);
|
|
zcache_put_pool(pool);
|
|
}
|
|
if (ret >= 0)
|
|
inc_zcache_flobj_found();
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_client_destroy_pool(int cli_id, int pool_id)
|
|
{
|
|
struct tmem_pool *pool = NULL;
|
|
struct zcache_client *cli = NULL;
|
|
int ret = -1;
|
|
|
|
if (pool_id < 0)
|
|
goto out;
|
|
if (cli_id == LOCAL_CLIENT)
|
|
cli = &zcache_host;
|
|
else if ((unsigned int)cli_id < MAX_CLIENTS)
|
|
cli = &zcache_clients[cli_id];
|
|
if (cli == NULL)
|
|
goto out;
|
|
atomic_inc(&cli->refcount);
|
|
pool = cli->tmem_pools[pool_id];
|
|
if (pool == NULL)
|
|
goto out;
|
|
cli->tmem_pools[pool_id] = NULL;
|
|
/* wait for pool activity on other cpus to quiesce */
|
|
while (atomic_read(&pool->refcount) != 0)
|
|
;
|
|
atomic_dec(&cli->refcount);
|
|
local_bh_disable();
|
|
ret = tmem_destroy_pool(pool);
|
|
local_bh_enable();
|
|
kfree(pool);
|
|
if (cli_id == LOCAL_CLIENT)
|
|
pr_info("%s: destroyed local pool id=%d\n", namestr, pool_id);
|
|
else
|
|
pr_info("%s: destroyed pool id=%d, client=%d\n",
|
|
namestr, pool_id, cli_id);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int zcache_new_pool(uint16_t cli_id, uint32_t flags)
|
|
{
|
|
int poolid = -1;
|
|
struct tmem_pool *pool;
|
|
struct zcache_client *cli = NULL;
|
|
|
|
if (cli_id == LOCAL_CLIENT)
|
|
cli = &zcache_host;
|
|
else if ((unsigned int)cli_id < MAX_CLIENTS)
|
|
cli = &zcache_clients[cli_id];
|
|
if (cli == NULL)
|
|
goto out;
|
|
atomic_inc(&cli->refcount);
|
|
pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
|
|
if (pool == NULL)
|
|
goto out;
|
|
|
|
for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
|
|
if (cli->tmem_pools[poolid] == NULL)
|
|
break;
|
|
if (poolid >= MAX_POOLS_PER_CLIENT) {
|
|
pr_info("%s: pool creation failed: max exceeded\n", namestr);
|
|
kfree(pool);
|
|
poolid = -1;
|
|
goto out;
|
|
}
|
|
atomic_set(&pool->refcount, 0);
|
|
pool->client = cli;
|
|
pool->pool_id = poolid;
|
|
tmem_new_pool(pool, flags);
|
|
cli->tmem_pools[poolid] = pool;
|
|
if (cli_id == LOCAL_CLIENT)
|
|
pr_info("%s: created %s local tmem pool, id=%d\n", namestr,
|
|
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
|
|
poolid);
|
|
else
|
|
pr_info("%s: created %s tmem pool, id=%d, client=%d\n", namestr,
|
|
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
|
|
poolid, cli_id);
|
|
out:
|
|
if (cli != NULL)
|
|
atomic_dec(&cli->refcount);
|
|
return poolid;
|
|
}
|
|
|
|
static int zcache_local_new_pool(uint32_t flags)
|
|
{
|
|
return zcache_new_pool(LOCAL_CLIENT, flags);
|
|
}
|
|
|
|
int zcache_autocreate_pool(unsigned int cli_id, unsigned int pool_id, bool eph)
|
|
{
|
|
struct tmem_pool *pool;
|
|
struct zcache_client *cli = NULL;
|
|
uint32_t flags = eph ? 0 : TMEM_POOL_PERSIST;
|
|
int ret = -1;
|
|
|
|
BUG_ON(!ramster_enabled);
|
|
if (cli_id == LOCAL_CLIENT)
|
|
goto out;
|
|
if (pool_id >= MAX_POOLS_PER_CLIENT)
|
|
goto out;
|
|
if (cli_id >= MAX_CLIENTS)
|
|
goto out;
|
|
|
|
cli = &zcache_clients[cli_id];
|
|
if ((eph && disable_cleancache) || (!eph && disable_frontswap)) {
|
|
pr_err("zcache_autocreate_pool: pool type disabled\n");
|
|
goto out;
|
|
}
|
|
if (!cli->allocated) {
|
|
if (zcache_new_client(cli_id)) {
|
|
pr_err("zcache_autocreate_pool: can't create client\n");
|
|
goto out;
|
|
}
|
|
cli = &zcache_clients[cli_id];
|
|
}
|
|
atomic_inc(&cli->refcount);
|
|
pool = cli->tmem_pools[pool_id];
|
|
if (pool != NULL) {
|
|
if (pool->persistent && eph) {
|
|
pr_err("zcache_autocreate_pool: type mismatch\n");
|
|
goto out;
|
|
}
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
|
|
if (pool == NULL)
|
|
goto out;
|
|
|
|
atomic_set(&pool->refcount, 0);
|
|
pool->client = cli;
|
|
pool->pool_id = pool_id;
|
|
tmem_new_pool(pool, flags);
|
|
cli->tmem_pools[pool_id] = pool;
|
|
pr_info("%s: AUTOcreated %s tmem poolid=%d, for remote client=%d\n",
|
|
namestr, flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
|
|
pool_id, cli_id);
|
|
ret = 0;
|
|
out:
|
|
if (cli != NULL)
|
|
atomic_dec(&cli->refcount);
|
|
return ret;
|
|
}
|
|
|
|
/**********
|
|
* Two kernel functionalities currently can be layered on top of tmem.
|
|
* These are "cleancache" which is used as a second-chance cache for clean
|
|
* page cache pages; and "frontswap" which is used for swap pages
|
|
* to avoid writes to disk. A generic "shim" is provided here for each
|
|
* to translate in-kernel semantics to zcache semantics.
|
|
*/
|
|
|
|
static void zcache_cleancache_put_page(int pool_id,
|
|
struct cleancache_filekey key,
|
|
pgoff_t index, struct page *page)
|
|
{
|
|
u32 ind = (u32) index;
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
|
|
if (!disable_cleancache_ignore_nonactive && !PageWasActive(page)) {
|
|
inc_zcache_eph_nonactive_puts_ignored();
|
|
return;
|
|
}
|
|
if (likely(ind == index))
|
|
(void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index,
|
|
page, PAGE_SIZE, false, 1);
|
|
}
|
|
|
|
static int zcache_cleancache_get_page(int pool_id,
|
|
struct cleancache_filekey key,
|
|
pgoff_t index, struct page *page)
|
|
{
|
|
u32 ind = (u32) index;
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
size_t size;
|
|
int ret = -1;
|
|
|
|
if (likely(ind == index)) {
|
|
ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index,
|
|
page, &size, false, 0);
|
|
BUG_ON(ret >= 0 && size != PAGE_SIZE);
|
|
if (ret == 0)
|
|
SetPageWasActive(page);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void zcache_cleancache_flush_page(int pool_id,
|
|
struct cleancache_filekey key,
|
|
pgoff_t index)
|
|
{
|
|
u32 ind = (u32) index;
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
|
|
if (likely(ind == index))
|
|
(void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
|
|
}
|
|
|
|
static void zcache_cleancache_flush_inode(int pool_id,
|
|
struct cleancache_filekey key)
|
|
{
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
|
|
(void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
|
|
}
|
|
|
|
static void zcache_cleancache_flush_fs(int pool_id)
|
|
{
|
|
if (pool_id >= 0)
|
|
(void)zcache_client_destroy_pool(LOCAL_CLIENT, pool_id);
|
|
}
|
|
|
|
static int zcache_cleancache_init_fs(size_t pagesize)
|
|
{
|
|
BUG_ON(sizeof(struct cleancache_filekey) !=
|
|
sizeof(struct tmem_oid));
|
|
BUG_ON(pagesize != PAGE_SIZE);
|
|
return zcache_local_new_pool(0);
|
|
}
|
|
|
|
static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
|
|
{
|
|
/* shared pools are unsupported and map to private */
|
|
BUG_ON(sizeof(struct cleancache_filekey) !=
|
|
sizeof(struct tmem_oid));
|
|
BUG_ON(pagesize != PAGE_SIZE);
|
|
return zcache_local_new_pool(0);
|
|
}
|
|
|
|
static struct cleancache_ops zcache_cleancache_ops = {
|
|
.put_page = zcache_cleancache_put_page,
|
|
.get_page = zcache_cleancache_get_page,
|
|
.invalidate_page = zcache_cleancache_flush_page,
|
|
.invalidate_inode = zcache_cleancache_flush_inode,
|
|
.invalidate_fs = zcache_cleancache_flush_fs,
|
|
.init_shared_fs = zcache_cleancache_init_shared_fs,
|
|
.init_fs = zcache_cleancache_init_fs
|
|
};
|
|
|
|
struct cleancache_ops *zcache_cleancache_register_ops(void)
|
|
{
|
|
struct cleancache_ops *old_ops =
|
|
cleancache_register_ops(&zcache_cleancache_ops);
|
|
|
|
return old_ops;
|
|
}
|
|
|
|
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
|
|
static int zcache_frontswap_poolid __read_mostly = -1;
|
|
|
|
/*
|
|
* Swizzling increases objects per swaptype, increasing tmem concurrency
|
|
* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
|
|
* Setting SWIZ_BITS to 27 basically reconstructs the swap entry from
|
|
* frontswap_get_page(), but has side-effects. Hence using 8.
|
|
*/
|
|
#define SWIZ_BITS 8
|
|
#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
|
|
#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
|
|
#define iswiz(_ind) (_ind >> SWIZ_BITS)
|
|
|
|
static inline struct tmem_oid oswiz(unsigned type, u32 ind)
|
|
{
|
|
struct tmem_oid oid = { .oid = { 0 } };
|
|
oid.oid[0] = _oswiz(type, ind);
|
|
return oid;
|
|
}
|
|
|
|
#ifdef CONFIG_ZCACHE_WRITEBACK
|
|
static void unswiz(struct tmem_oid oid, u32 index,
|
|
unsigned *type, pgoff_t *offset)
|
|
{
|
|
*type = (unsigned)(oid.oid[0] >> SWIZ_BITS);
|
|
*offset = (pgoff_t)((index << SWIZ_BITS) |
|
|
(oid.oid[0] & SWIZ_MASK));
|
|
}
|
|
#endif
|
|
|
|
static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
|
|
struct page *page)
|
|
{
|
|
u64 ind64 = (u64)offset;
|
|
u32 ind = (u32)offset;
|
|
struct tmem_oid oid = oswiz(type, ind);
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
|
|
BUG_ON(!PageLocked(page));
|
|
if (!disable_frontswap_ignore_nonactive && !PageWasActive(page)) {
|
|
inc_zcache_pers_nonactive_puts_ignored();
|
|
ret = -ERANGE;
|
|
goto out;
|
|
}
|
|
if (likely(ind64 == ind)) {
|
|
local_irq_save(flags);
|
|
ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
|
|
&oid, iswiz(ind),
|
|
page, PAGE_SIZE, false, 0);
|
|
local_irq_restore(flags);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/* returns 0 if the page was successfully gotten from frontswap, -1 if
|
|
* was not present (should never happen!) */
|
|
static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
|
|
struct page *page)
|
|
{
|
|
u64 ind64 = (u64)offset;
|
|
u32 ind = (u32)offset;
|
|
struct tmem_oid oid = oswiz(type, ind);
|
|
size_t size;
|
|
int ret = -1, get_and_free;
|
|
|
|
if (frontswap_has_exclusive_gets)
|
|
get_and_free = 1;
|
|
else
|
|
get_and_free = -1;
|
|
BUG_ON(!PageLocked(page));
|
|
if (likely(ind64 == ind)) {
|
|
ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
|
|
&oid, iswiz(ind),
|
|
page, &size, false, get_and_free);
|
|
BUG_ON(ret >= 0 && size != PAGE_SIZE);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* flush a single page from frontswap */
|
|
static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
|
|
{
|
|
u64 ind64 = (u64)offset;
|
|
u32 ind = (u32)offset;
|
|
struct tmem_oid oid = oswiz(type, ind);
|
|
|
|
if (likely(ind64 == ind))
|
|
(void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
|
|
&oid, iswiz(ind));
|
|
}
|
|
|
|
/* flush all pages from the passed swaptype */
|
|
static void zcache_frontswap_flush_area(unsigned type)
|
|
{
|
|
struct tmem_oid oid;
|
|
int ind;
|
|
|
|
for (ind = SWIZ_MASK; ind >= 0; ind--) {
|
|
oid = oswiz(type, ind);
|
|
(void)zcache_flush_object(LOCAL_CLIENT,
|
|
zcache_frontswap_poolid, &oid);
|
|
}
|
|
}
|
|
|
|
static void zcache_frontswap_init(unsigned ignored)
|
|
{
|
|
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
|
|
if (zcache_frontswap_poolid < 0)
|
|
zcache_frontswap_poolid =
|
|
zcache_local_new_pool(TMEM_POOL_PERSIST);
|
|
}
|
|
|
|
static struct frontswap_ops zcache_frontswap_ops = {
|
|
.store = zcache_frontswap_put_page,
|
|
.load = zcache_frontswap_get_page,
|
|
.invalidate_page = zcache_frontswap_flush_page,
|
|
.invalidate_area = zcache_frontswap_flush_area,
|
|
.init = zcache_frontswap_init
|
|
};
|
|
|
|
struct frontswap_ops *zcache_frontswap_register_ops(void)
|
|
{
|
|
struct frontswap_ops *old_ops =
|
|
frontswap_register_ops(&zcache_frontswap_ops);
|
|
|
|
return old_ops;
|
|
}
|
|
|
|
/*
|
|
* zcache initialization
|
|
* NOTE FOR NOW zcache or ramster MUST BE PROVIDED AS A KERNEL BOOT PARAMETER
|
|
* OR NOTHING HAPPENS!
|
|
*/
|
|
|
|
#ifndef CONFIG_ZCACHE_MODULE
|
|
static int __init enable_zcache(char *s)
|
|
{
|
|
zcache_enabled = true;
|
|
return 1;
|
|
}
|
|
__setup("zcache", enable_zcache);
|
|
|
|
static int __init enable_ramster(char *s)
|
|
{
|
|
zcache_enabled = true;
|
|
#ifdef CONFIG_RAMSTER
|
|
ramster_enabled = true;
|
|
#endif
|
|
return 1;
|
|
}
|
|
__setup("ramster", enable_ramster);
|
|
|
|
/* allow independent dynamic disabling of cleancache and frontswap */
|
|
|
|
static int __init no_cleancache(char *s)
|
|
{
|
|
disable_cleancache = true;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nocleancache", no_cleancache);
|
|
|
|
static int __init no_frontswap(char *s)
|
|
{
|
|
disable_frontswap = true;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nofrontswap", no_frontswap);
|
|
|
|
static int __init no_frontswap_exclusive_gets(char *s)
|
|
{
|
|
frontswap_has_exclusive_gets = false;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nofrontswapexclusivegets", no_frontswap_exclusive_gets);
|
|
|
|
static int __init no_frontswap_ignore_nonactive(char *s)
|
|
{
|
|
disable_frontswap_ignore_nonactive = true;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nofrontswapignorenonactive", no_frontswap_ignore_nonactive);
|
|
|
|
static int __init no_cleancache_ignore_nonactive(char *s)
|
|
{
|
|
disable_cleancache_ignore_nonactive = true;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nocleancacheignorenonactive", no_cleancache_ignore_nonactive);
|
|
|
|
static int __init enable_zcache_compressor(char *s)
|
|
{
|
|
strlcpy(zcache_comp_name, s, sizeof(zcache_comp_name));
|
|
zcache_enabled = true;
|
|
return 1;
|
|
}
|
|
__setup("zcache=", enable_zcache_compressor);
|
|
#endif
|
|
|
|
|
|
static int zcache_comp_init(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
/* check crypto algorithm */
|
|
#ifdef CONFIG_ZCACHE_MODULE
|
|
ret = crypto_has_comp(zcache_comp_name, 0, 0);
|
|
if (!ret) {
|
|
ret = -1;
|
|
goto out;
|
|
}
|
|
#else
|
|
if (*zcache_comp_name != '\0') {
|
|
ret = crypto_has_comp(zcache_comp_name, 0, 0);
|
|
if (!ret) {
|
|
pr_info("zcache: %s not supported\n",
|
|
zcache_comp_name);
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
}
|
|
if (!ret)
|
|
strcpy(zcache_comp_name, "lzo");
|
|
ret = crypto_has_comp(zcache_comp_name, 0, 0);
|
|
if (!ret) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
#endif
|
|
pr_info("zcache: using %s compressor\n", zcache_comp_name);
|
|
|
|
/* alloc percpu transforms */
|
|
ret = 0;
|
|
zcache_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
|
|
if (!zcache_comp_pcpu_tfms)
|
|
ret = 1;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_init(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
#ifdef CONFIG_ZCACHE_MODULE
|
|
zcache_enabled = 1;
|
|
#endif
|
|
if (ramster_enabled) {
|
|
namestr = "ramster";
|
|
ramster_register_pamops(&zcache_pamops);
|
|
}
|
|
zcache_debugfs_init();
|
|
if (zcache_enabled) {
|
|
unsigned int cpu;
|
|
|
|
tmem_register_hostops(&zcache_hostops);
|
|
tmem_register_pamops(&zcache_pamops);
|
|
ret = register_cpu_notifier(&zcache_cpu_notifier_block);
|
|
if (ret) {
|
|
pr_err("%s: can't register cpu notifier\n", namestr);
|
|
goto out;
|
|
}
|
|
ret = zcache_comp_init();
|
|
if (ret) {
|
|
pr_err("%s: compressor initialization failed\n",
|
|
namestr);
|
|
goto out;
|
|
}
|
|
for_each_online_cpu(cpu) {
|
|
void *pcpu = (void *)(long)cpu;
|
|
zcache_cpu_notifier(&zcache_cpu_notifier_block,
|
|
CPU_UP_PREPARE, pcpu);
|
|
}
|
|
}
|
|
zcache_objnode_cache = kmem_cache_create("zcache_objnode",
|
|
sizeof(struct tmem_objnode), 0, 0, NULL);
|
|
zcache_obj_cache = kmem_cache_create("zcache_obj",
|
|
sizeof(struct tmem_obj), 0, 0, NULL);
|
|
ret = zcache_new_client(LOCAL_CLIENT);
|
|
if (ret) {
|
|
pr_err("%s: can't create client\n", namestr);
|
|
goto out;
|
|
}
|
|
zbud_init();
|
|
if (zcache_enabled && !disable_cleancache) {
|
|
struct cleancache_ops *old_ops;
|
|
|
|
register_shrinker(&zcache_shrinker);
|
|
old_ops = zcache_cleancache_register_ops();
|
|
pr_info("%s: cleancache enabled using kernel transcendent "
|
|
"memory and compression buddies\n", namestr);
|
|
#ifdef CONFIG_ZCACHE_DEBUG
|
|
pr_info("%s: cleancache: ignorenonactive = %d\n",
|
|
namestr, !disable_cleancache_ignore_nonactive);
|
|
#endif
|
|
if (old_ops != NULL)
|
|
pr_warn("%s: cleancache_ops overridden\n", namestr);
|
|
}
|
|
if (zcache_enabled && !disable_frontswap) {
|
|
struct frontswap_ops *old_ops;
|
|
|
|
old_ops = zcache_frontswap_register_ops();
|
|
if (frontswap_has_exclusive_gets)
|
|
frontswap_tmem_exclusive_gets(true);
|
|
pr_info("%s: frontswap enabled using kernel transcendent "
|
|
"memory and compression buddies\n", namestr);
|
|
#ifdef CONFIG_ZCACHE_DEBUG
|
|
pr_info("%s: frontswap: excl gets = %d active only = %d\n",
|
|
namestr, frontswap_has_exclusive_gets,
|
|
!disable_frontswap_ignore_nonactive);
|
|
#endif
|
|
if (IS_ERR(old_ops) || old_ops) {
|
|
if (IS_ERR(old_ops))
|
|
return PTR_RET(old_ops);
|
|
pr_warn("%s: frontswap_ops overridden\n", namestr);
|
|
}
|
|
}
|
|
if (ramster_enabled)
|
|
ramster_init(!disable_cleancache, !disable_frontswap,
|
|
frontswap_has_exclusive_gets,
|
|
!disable_frontswap_selfshrink);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_ZCACHE_MODULE
|
|
#ifdef CONFIG_RAMSTER
|
|
module_param(ramster_enabled, bool, S_IRUGO);
|
|
module_param(disable_frontswap_selfshrink, int, S_IRUGO);
|
|
#endif
|
|
module_param(disable_cleancache, bool, S_IRUGO);
|
|
module_param(disable_frontswap, bool, S_IRUGO);
|
|
#ifdef FRONTSWAP_HAS_EXCLUSIVE_GETS
|
|
module_param(frontswap_has_exclusive_gets, bool, S_IRUGO);
|
|
#endif
|
|
module_param(disable_frontswap_ignore_nonactive, bool, S_IRUGO);
|
|
module_param(zcache_comp_name, charp, S_IRUGO);
|
|
module_init(zcache_init);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
|
|
MODULE_DESCRIPTION("In-kernel compression of cleancache/frontswap pages");
|
|
#else
|
|
late_initcall(zcache_init);
|
|
#endif
|