988 lines
27 KiB
C
988 lines
27 KiB
C
/*
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* linux/mm/percpu.c - percpu memory allocator
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*
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* Copyright (C) 2009 SUSE Linux Products GmbH
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* Copyright (C) 2009 Tejun Heo <tj@kernel.org>
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*
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* This file is released under the GPLv2.
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*
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* This is percpu allocator which can handle both static and dynamic
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* areas. Percpu areas are allocated in chunks in vmalloc area. Each
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* chunk is consisted of num_possible_cpus() units and the first chunk
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* is used for static percpu variables in the kernel image (special
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* boot time alloc/init handling necessary as these areas need to be
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* brought up before allocation services are running). Unit grows as
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* necessary and all units grow or shrink in unison. When a chunk is
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* filled up, another chunk is allocated. ie. in vmalloc area
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*
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* c0 c1 c2
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* ------------------- ------------------- ------------
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* | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
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* ------------------- ...... ------------------- .... ------------
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*
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* Allocation is done in offset-size areas of single unit space. Ie,
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* an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
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* c1:u1, c1:u2 and c1:u3. Percpu access can be done by configuring
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* percpu base registers UNIT_SIZE apart.
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*
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* There are usually many small percpu allocations many of them as
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* small as 4 bytes. The allocator organizes chunks into lists
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* according to free size and tries to allocate from the fullest one.
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* Each chunk keeps the maximum contiguous area size hint which is
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* guaranteed to be eqaul to or larger than the maximum contiguous
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* area in the chunk. This helps the allocator not to iterate the
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* chunk maps unnecessarily.
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*
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* Allocation state in each chunk is kept using an array of integers
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* on chunk->map. A positive value in the map represents a free
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* region and negative allocated. Allocation inside a chunk is done
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* by scanning this map sequentially and serving the first matching
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* entry. This is mostly copied from the percpu_modalloc() allocator.
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* Chunks are also linked into a rb tree to ease address to chunk
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* mapping during free.
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*
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* To use this allocator, arch code should do the followings.
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*
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* - define CONFIG_HAVE_DYNAMIC_PER_CPU_AREA
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*
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* - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
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* regular address to percpu pointer and back
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*
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* - use pcpu_setup_first_chunk() during percpu area initialization to
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* setup the first chunk containing the kernel static percpu area
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*/
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#include <linux/bitmap.h>
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#include <linux/bootmem.h>
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#include <linux/list.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/percpu.h>
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#include <linux/pfn.h>
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#include <linux/rbtree.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
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#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
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struct pcpu_chunk {
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struct list_head list; /* linked to pcpu_slot lists */
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struct rb_node rb_node; /* key is chunk->vm->addr */
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int free_size; /* free bytes in the chunk */
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int contig_hint; /* max contiguous size hint */
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struct vm_struct *vm; /* mapped vmalloc region */
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int map_used; /* # of map entries used */
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int map_alloc; /* # of map entries allocated */
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int *map; /* allocation map */
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bool immutable; /* no [de]population allowed */
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struct page **page; /* points to page array */
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struct page *page_ar[]; /* #cpus * UNIT_PAGES */
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};
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static int pcpu_unit_pages __read_mostly;
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static int pcpu_unit_size __read_mostly;
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static int pcpu_chunk_size __read_mostly;
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static int pcpu_nr_slots __read_mostly;
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static size_t pcpu_chunk_struct_size __read_mostly;
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/* the address of the first chunk which starts with the kernel static area */
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void *pcpu_base_addr __read_mostly;
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EXPORT_SYMBOL_GPL(pcpu_base_addr);
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/*
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* One mutex to rule them all.
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*
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* The following mutex is grabbed in the outermost public alloc/free
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* interface functions and released only when the operation is
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* complete. As such, every function in this file other than the
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* outermost functions are called under pcpu_mutex.
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*
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* It can easily be switched to use spinlock such that only the area
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* allocation and page population commit are protected with it doing
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* actual [de]allocation without holding any lock. However, given
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* what this allocator does, I think it's better to let them run
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* sequentially.
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*/
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static DEFINE_MUTEX(pcpu_mutex);
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static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
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static struct rb_root pcpu_addr_root = RB_ROOT; /* chunks by address */
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static int __pcpu_size_to_slot(int size)
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{
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int highbit = fls(size); /* size is in bytes */
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return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
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}
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static int pcpu_size_to_slot(int size)
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{
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if (size == pcpu_unit_size)
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return pcpu_nr_slots - 1;
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return __pcpu_size_to_slot(size);
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}
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static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
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{
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if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
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return 0;
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return pcpu_size_to_slot(chunk->free_size);
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}
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static int pcpu_page_idx(unsigned int cpu, int page_idx)
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{
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return cpu * pcpu_unit_pages + page_idx;
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}
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static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk,
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unsigned int cpu, int page_idx)
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{
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return &chunk->page[pcpu_page_idx(cpu, page_idx)];
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}
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static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
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unsigned int cpu, int page_idx)
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{
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return (unsigned long)chunk->vm->addr +
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(pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT);
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}
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static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
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int page_idx)
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{
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return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
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}
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/**
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* pcpu_realloc - versatile realloc
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* @p: the current pointer (can be NULL for new allocations)
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* @size: the current size in bytes (can be 0 for new allocations)
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* @new_size: the wanted new size in bytes (can be 0 for free)
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*
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* More robust realloc which can be used to allocate, resize or free a
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* memory area of arbitrary size. If the needed size goes over
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* PAGE_SIZE, kernel VM is used.
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*
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* RETURNS:
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* The new pointer on success, NULL on failure.
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*/
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static void *pcpu_realloc(void *p, size_t size, size_t new_size)
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{
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void *new;
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if (new_size <= PAGE_SIZE)
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new = kmalloc(new_size, GFP_KERNEL);
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else
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new = vmalloc(new_size);
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if (new_size && !new)
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return NULL;
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memcpy(new, p, min(size, new_size));
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if (new_size > size)
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memset(new + size, 0, new_size - size);
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if (size <= PAGE_SIZE)
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kfree(p);
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else
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vfree(p);
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return new;
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}
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/**
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* pcpu_chunk_relocate - put chunk in the appropriate chunk slot
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* @chunk: chunk of interest
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* @oslot: the previous slot it was on
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*
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* This function is called after an allocation or free changed @chunk.
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* New slot according to the changed state is determined and @chunk is
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* moved to the slot.
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*/
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static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
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{
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int nslot = pcpu_chunk_slot(chunk);
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if (oslot != nslot) {
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if (oslot < nslot)
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list_move(&chunk->list, &pcpu_slot[nslot]);
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else
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list_move_tail(&chunk->list, &pcpu_slot[nslot]);
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}
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}
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static struct rb_node **pcpu_chunk_rb_search(void *addr,
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struct rb_node **parentp)
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{
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struct rb_node **p = &pcpu_addr_root.rb_node;
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struct rb_node *parent = NULL;
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struct pcpu_chunk *chunk;
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while (*p) {
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parent = *p;
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chunk = rb_entry(parent, struct pcpu_chunk, rb_node);
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if (addr < chunk->vm->addr)
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p = &(*p)->rb_left;
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else if (addr > chunk->vm->addr)
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p = &(*p)->rb_right;
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else
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break;
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}
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if (parentp)
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*parentp = parent;
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return p;
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}
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/**
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* pcpu_chunk_addr_search - search for chunk containing specified address
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* @addr: address to search for
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*
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* Look for chunk which might contain @addr. More specifically, it
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* searchs for the chunk with the highest start address which isn't
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* beyond @addr.
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*
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* RETURNS:
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* The address of the found chunk.
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*/
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static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
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{
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struct rb_node *n, *parent;
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struct pcpu_chunk *chunk;
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n = *pcpu_chunk_rb_search(addr, &parent);
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if (!n) {
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/* no exactly matching chunk, the parent is the closest */
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n = parent;
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BUG_ON(!n);
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}
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chunk = rb_entry(n, struct pcpu_chunk, rb_node);
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if (addr < chunk->vm->addr) {
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/* the parent was the next one, look for the previous one */
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n = rb_prev(n);
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BUG_ON(!n);
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chunk = rb_entry(n, struct pcpu_chunk, rb_node);
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}
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return chunk;
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}
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/**
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* pcpu_chunk_addr_insert - insert chunk into address rb tree
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* @new: chunk to insert
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*
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* Insert @new into address rb tree.
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*/
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static void pcpu_chunk_addr_insert(struct pcpu_chunk *new)
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{
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struct rb_node **p, *parent;
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p = pcpu_chunk_rb_search(new->vm->addr, &parent);
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BUG_ON(*p);
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rb_link_node(&new->rb_node, parent, p);
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rb_insert_color(&new->rb_node, &pcpu_addr_root);
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}
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/**
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* pcpu_split_block - split a map block
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* @chunk: chunk of interest
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* @i: index of map block to split
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* @head: head size in bytes (can be 0)
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* @tail: tail size in bytes (can be 0)
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*
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* Split the @i'th map block into two or three blocks. If @head is
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* non-zero, @head bytes block is inserted before block @i moving it
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* to @i+1 and reducing its size by @head bytes.
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*
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* If @tail is non-zero, the target block, which can be @i or @i+1
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* depending on @head, is reduced by @tail bytes and @tail byte block
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* is inserted after the target block.
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*
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* RETURNS:
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* 0 on success, -errno on failure.
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*/
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static int pcpu_split_block(struct pcpu_chunk *chunk, int i, int head, int tail)
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{
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int nr_extra = !!head + !!tail;
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int target = chunk->map_used + nr_extra;
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/* reallocation required? */
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if (chunk->map_alloc < target) {
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int new_alloc;
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int *new;
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new_alloc = PCPU_DFL_MAP_ALLOC;
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while (new_alloc < target)
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new_alloc *= 2;
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if (chunk->map_alloc < PCPU_DFL_MAP_ALLOC) {
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/*
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* map_alloc smaller than the default size
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* indicates that the chunk is one of the
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* first chunks and still using static map.
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* Allocate a dynamic one and copy.
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*/
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new = pcpu_realloc(NULL, 0, new_alloc * sizeof(new[0]));
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if (new)
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memcpy(new, chunk->map,
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chunk->map_alloc * sizeof(new[0]));
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} else
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new = pcpu_realloc(chunk->map,
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chunk->map_alloc * sizeof(new[0]),
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new_alloc * sizeof(new[0]));
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if (!new)
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return -ENOMEM;
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chunk->map_alloc = new_alloc;
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chunk->map = new;
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}
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/* insert a new subblock */
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memmove(&chunk->map[i + nr_extra], &chunk->map[i],
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sizeof(chunk->map[0]) * (chunk->map_used - i));
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chunk->map_used += nr_extra;
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if (head) {
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chunk->map[i + 1] = chunk->map[i] - head;
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chunk->map[i++] = head;
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}
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if (tail) {
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chunk->map[i++] -= tail;
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chunk->map[i] = tail;
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}
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return 0;
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}
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/**
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* pcpu_alloc_area - allocate area from a pcpu_chunk
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* @chunk: chunk of interest
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* @size: wanted size in bytes
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* @align: wanted align
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*
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* Try to allocate @size bytes area aligned at @align from @chunk.
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* Note that this function only allocates the offset. It doesn't
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* populate or map the area.
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*
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* RETURNS:
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* Allocated offset in @chunk on success, -errno on failure.
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*/
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static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
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{
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int oslot = pcpu_chunk_slot(chunk);
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int max_contig = 0;
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int i, off;
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for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
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bool is_last = i + 1 == chunk->map_used;
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int head, tail;
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/* extra for alignment requirement */
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head = ALIGN(off, align) - off;
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BUG_ON(i == 0 && head != 0);
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if (chunk->map[i] < 0)
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continue;
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if (chunk->map[i] < head + size) {
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max_contig = max(chunk->map[i], max_contig);
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continue;
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}
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/*
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* If head is small or the previous block is free,
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* merge'em. Note that 'small' is defined as smaller
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* than sizeof(int), which is very small but isn't too
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* uncommon for percpu allocations.
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*/
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if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
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if (chunk->map[i - 1] > 0)
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chunk->map[i - 1] += head;
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else {
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chunk->map[i - 1] -= head;
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chunk->free_size -= head;
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}
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chunk->map[i] -= head;
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off += head;
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head = 0;
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}
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/* if tail is small, just keep it around */
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tail = chunk->map[i] - head - size;
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if (tail < sizeof(int))
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tail = 0;
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/* split if warranted */
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if (head || tail) {
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if (pcpu_split_block(chunk, i, head, tail))
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return -ENOMEM;
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if (head) {
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i++;
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off += head;
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max_contig = max(chunk->map[i - 1], max_contig);
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}
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if (tail)
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max_contig = max(chunk->map[i + 1], max_contig);
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}
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/* update hint and mark allocated */
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if (is_last)
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chunk->contig_hint = max_contig; /* fully scanned */
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else
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chunk->contig_hint = max(chunk->contig_hint,
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max_contig);
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chunk->free_size -= chunk->map[i];
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chunk->map[i] = -chunk->map[i];
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pcpu_chunk_relocate(chunk, oslot);
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return off;
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}
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chunk->contig_hint = max_contig; /* fully scanned */
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pcpu_chunk_relocate(chunk, oslot);
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/*
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* Tell the upper layer that this chunk has no area left.
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* Note that this is not an error condition but a notification
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* to upper layer that it needs to look at other chunks.
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* -ENOSPC is chosen as it isn't used in memory subsystem and
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* matches the meaning in a way.
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*/
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return -ENOSPC;
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}
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/**
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* pcpu_free_area - free area to a pcpu_chunk
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* @chunk: chunk of interest
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* @freeme: offset of area to free
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*
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* Free area starting from @freeme to @chunk. Note that this function
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* only modifies the allocation map. It doesn't depopulate or unmap
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* the area.
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*/
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static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
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{
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int oslot = pcpu_chunk_slot(chunk);
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int i, off;
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for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
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if (off == freeme)
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break;
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BUG_ON(off != freeme);
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BUG_ON(chunk->map[i] > 0);
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chunk->map[i] = -chunk->map[i];
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chunk->free_size += chunk->map[i];
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/* merge with previous? */
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if (i > 0 && chunk->map[i - 1] >= 0) {
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chunk->map[i - 1] += chunk->map[i];
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chunk->map_used--;
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memmove(&chunk->map[i], &chunk->map[i + 1],
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(chunk->map_used - i) * sizeof(chunk->map[0]));
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i--;
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}
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/* merge with next? */
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if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
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chunk->map[i] += chunk->map[i + 1];
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chunk->map_used--;
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memmove(&chunk->map[i + 1], &chunk->map[i + 2],
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(chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
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}
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chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
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pcpu_chunk_relocate(chunk, oslot);
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}
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/**
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* pcpu_unmap - unmap pages out of a pcpu_chunk
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* @chunk: chunk of interest
|
|
* @page_start: page index of the first page to unmap
|
|
* @page_end: page index of the last page to unmap + 1
|
|
* @flush: whether to flush cache and tlb or not
|
|
*
|
|
* For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
|
|
* If @flush is true, vcache is flushed before unmapping and tlb
|
|
* after.
|
|
*/
|
|
static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
|
|
bool flush)
|
|
{
|
|
unsigned int last = num_possible_cpus() - 1;
|
|
unsigned int cpu;
|
|
|
|
/* unmap must not be done on immutable chunk */
|
|
WARN_ON(chunk->immutable);
|
|
|
|
/*
|
|
* Each flushing trial can be very expensive, issue flush on
|
|
* the whole region at once rather than doing it for each cpu.
|
|
* This could be an overkill but is more scalable.
|
|
*/
|
|
if (flush)
|
|
flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
|
|
pcpu_chunk_addr(chunk, last, page_end));
|
|
|
|
for_each_possible_cpu(cpu)
|
|
unmap_kernel_range_noflush(
|
|
pcpu_chunk_addr(chunk, cpu, page_start),
|
|
(page_end - page_start) << PAGE_SHIFT);
|
|
|
|
/* ditto as flush_cache_vunmap() */
|
|
if (flush)
|
|
flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
|
|
pcpu_chunk_addr(chunk, last, page_end));
|
|
}
|
|
|
|
/**
|
|
* pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
|
|
* @chunk: chunk to depopulate
|
|
* @off: offset to the area to depopulate
|
|
* @size: size of the area to depopulate in bytes
|
|
* @flush: whether to flush cache and tlb or not
|
|
*
|
|
* For each cpu, depopulate and unmap pages [@page_start,@page_end)
|
|
* from @chunk. If @flush is true, vcache is flushed before unmapping
|
|
* and tlb after.
|
|
*/
|
|
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
|
|
bool flush)
|
|
{
|
|
int page_start = PFN_DOWN(off);
|
|
int page_end = PFN_UP(off + size);
|
|
int unmap_start = -1;
|
|
int uninitialized_var(unmap_end);
|
|
unsigned int cpu;
|
|
int i;
|
|
|
|
for (i = page_start; i < page_end; i++) {
|
|
for_each_possible_cpu(cpu) {
|
|
struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
|
|
|
|
if (!*pagep)
|
|
continue;
|
|
|
|
__free_page(*pagep);
|
|
|
|
/*
|
|
* If it's partial depopulation, it might get
|
|
* populated or depopulated again. Mark the
|
|
* page gone.
|
|
*/
|
|
*pagep = NULL;
|
|
|
|
unmap_start = unmap_start < 0 ? i : unmap_start;
|
|
unmap_end = i + 1;
|
|
}
|
|
}
|
|
|
|
if (unmap_start >= 0)
|
|
pcpu_unmap(chunk, unmap_start, unmap_end, flush);
|
|
}
|
|
|
|
/**
|
|
* pcpu_map - map pages into a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @page_start: page index of the first page to map
|
|
* @page_end: page index of the last page to map + 1
|
|
*
|
|
* For each cpu, map pages [@page_start,@page_end) into @chunk.
|
|
* vcache is flushed afterwards.
|
|
*/
|
|
static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
|
|
{
|
|
unsigned int last = num_possible_cpus() - 1;
|
|
unsigned int cpu;
|
|
int err;
|
|
|
|
/* map must not be done on immutable chunk */
|
|
WARN_ON(chunk->immutable);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
err = map_kernel_range_noflush(
|
|
pcpu_chunk_addr(chunk, cpu, page_start),
|
|
(page_end - page_start) << PAGE_SHIFT,
|
|
PAGE_KERNEL,
|
|
pcpu_chunk_pagep(chunk, cpu, page_start));
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
/* flush at once, please read comments in pcpu_unmap() */
|
|
flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start),
|
|
pcpu_chunk_addr(chunk, last, page_end));
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* pcpu_populate_chunk - populate and map an area of a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @off: offset to the area to populate
|
|
* @size: size of the area to populate in bytes
|
|
*
|
|
* For each cpu, populate and map pages [@page_start,@page_end) into
|
|
* @chunk. The area is cleared on return.
|
|
*/
|
|
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
|
|
{
|
|
const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
|
|
int page_start = PFN_DOWN(off);
|
|
int page_end = PFN_UP(off + size);
|
|
int map_start = -1;
|
|
int uninitialized_var(map_end);
|
|
unsigned int cpu;
|
|
int i;
|
|
|
|
for (i = page_start; i < page_end; i++) {
|
|
if (pcpu_chunk_page_occupied(chunk, i)) {
|
|
if (map_start >= 0) {
|
|
if (pcpu_map(chunk, map_start, map_end))
|
|
goto err;
|
|
map_start = -1;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
map_start = map_start < 0 ? i : map_start;
|
|
map_end = i + 1;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
|
|
|
|
*pagep = alloc_pages_node(cpu_to_node(cpu),
|
|
alloc_mask, 0);
|
|
if (!*pagep)
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
if (map_start >= 0 && pcpu_map(chunk, map_start, map_end))
|
|
goto err;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0,
|
|
size);
|
|
|
|
return 0;
|
|
err:
|
|
/* likely under heavy memory pressure, give memory back */
|
|
pcpu_depopulate_chunk(chunk, off, size, true);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void free_pcpu_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
if (!chunk)
|
|
return;
|
|
if (chunk->vm)
|
|
free_vm_area(chunk->vm);
|
|
pcpu_realloc(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]), 0);
|
|
kfree(chunk);
|
|
}
|
|
|
|
static struct pcpu_chunk *alloc_pcpu_chunk(void)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
|
|
chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
|
|
if (!chunk)
|
|
return NULL;
|
|
|
|
chunk->map = pcpu_realloc(NULL, 0,
|
|
PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
|
|
chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
|
|
chunk->map[chunk->map_used++] = pcpu_unit_size;
|
|
chunk->page = chunk->page_ar;
|
|
|
|
chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL);
|
|
if (!chunk->vm) {
|
|
free_pcpu_chunk(chunk);
|
|
return NULL;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&chunk->list);
|
|
chunk->free_size = pcpu_unit_size;
|
|
chunk->contig_hint = pcpu_unit_size;
|
|
|
|
return chunk;
|
|
}
|
|
|
|
/**
|
|
* __alloc_percpu - allocate percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Allocate percpu area of @size bytes aligned at @align. Might
|
|
* sleep. Might trigger writeouts.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void *__alloc_percpu(size_t size, size_t align)
|
|
{
|
|
void *ptr = NULL;
|
|
struct pcpu_chunk *chunk;
|
|
int slot, off;
|
|
|
|
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
|
|
WARN(true, "illegal size (%zu) or align (%zu) for "
|
|
"percpu allocation\n", size, align);
|
|
return NULL;
|
|
}
|
|
|
|
mutex_lock(&pcpu_mutex);
|
|
|
|
/* allocate area */
|
|
for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
|
|
list_for_each_entry(chunk, &pcpu_slot[slot], list) {
|
|
if (size > chunk->contig_hint)
|
|
continue;
|
|
off = pcpu_alloc_area(chunk, size, align);
|
|
if (off >= 0)
|
|
goto area_found;
|
|
if (off != -ENOSPC)
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
|
|
/* hmmm... no space left, create a new chunk */
|
|
chunk = alloc_pcpu_chunk();
|
|
if (!chunk)
|
|
goto out_unlock;
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
pcpu_chunk_addr_insert(chunk);
|
|
|
|
off = pcpu_alloc_area(chunk, size, align);
|
|
if (off < 0)
|
|
goto out_unlock;
|
|
|
|
area_found:
|
|
/* populate, map and clear the area */
|
|
if (pcpu_populate_chunk(chunk, off, size)) {
|
|
pcpu_free_area(chunk, off);
|
|
goto out_unlock;
|
|
}
|
|
|
|
ptr = __addr_to_pcpu_ptr(chunk->vm->addr + off);
|
|
out_unlock:
|
|
mutex_unlock(&pcpu_mutex);
|
|
return ptr;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__alloc_percpu);
|
|
|
|
static void pcpu_kill_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
WARN_ON(chunk->immutable);
|
|
pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false);
|
|
list_del(&chunk->list);
|
|
rb_erase(&chunk->rb_node, &pcpu_addr_root);
|
|
free_pcpu_chunk(chunk);
|
|
}
|
|
|
|
/**
|
|
* free_percpu - free percpu area
|
|
* @ptr: pointer to area to free
|
|
*
|
|
* Free percpu area @ptr. Might sleep.
|
|
*/
|
|
void free_percpu(void *ptr)
|
|
{
|
|
void *addr = __pcpu_ptr_to_addr(ptr);
|
|
struct pcpu_chunk *chunk;
|
|
int off;
|
|
|
|
if (!ptr)
|
|
return;
|
|
|
|
mutex_lock(&pcpu_mutex);
|
|
|
|
chunk = pcpu_chunk_addr_search(addr);
|
|
off = addr - chunk->vm->addr;
|
|
|
|
pcpu_free_area(chunk, off);
|
|
|
|
/* the chunk became fully free, kill one if there are other free ones */
|
|
if (chunk->free_size == pcpu_unit_size) {
|
|
struct pcpu_chunk *pos;
|
|
|
|
list_for_each_entry(pos,
|
|
&pcpu_slot[pcpu_chunk_slot(chunk)], list)
|
|
if (pos != chunk) {
|
|
pcpu_kill_chunk(pos);
|
|
break;
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&pcpu_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(free_percpu);
|
|
|
|
/**
|
|
* pcpu_setup_first_chunk - initialize the first percpu chunk
|
|
* @get_page_fn: callback to fetch page pointer
|
|
* @static_size: the size of static percpu area in bytes
|
|
* @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto
|
|
* @dyn_size: free size for dynamic allocation in bytes, -1 for auto
|
|
* @base_addr: mapped address, NULL for auto
|
|
* @populate_pte_fn: callback to allocate pagetable, NULL if unnecessary
|
|
*
|
|
* Initialize the first percpu chunk which contains the kernel static
|
|
* perpcu area. This function is to be called from arch percpu area
|
|
* setup path. The first two parameters are mandatory. The rest are
|
|
* optional.
|
|
*
|
|
* @get_page_fn() should return pointer to percpu page given cpu
|
|
* number and page number. It should at least return enough pages to
|
|
* cover the static area. The returned pages for static area should
|
|
* have been initialized with valid data. If @unit_size is specified,
|
|
* it can also return pages after the static area. NULL return
|
|
* indicates end of pages for the cpu. Note that @get_page_fn() must
|
|
* return the same number of pages for all cpus.
|
|
*
|
|
* @unit_size, if non-negative, specifies unit size and must be
|
|
* aligned to PAGE_SIZE and equal to or larger than @static_size +
|
|
* @dyn_size.
|
|
*
|
|
* @dyn_size, if non-negative, limits the number of bytes available
|
|
* for dynamic allocation in the first chunk. Specifying non-negative
|
|
* value make percpu leave alone the area beyond @static_size +
|
|
* @dyn_size.
|
|
*
|
|
* Non-null @base_addr means that the caller already allocated virtual
|
|
* region for the first chunk and mapped it. percpu must not mess
|
|
* with the chunk. Note that @base_addr with 0 @unit_size or non-NULL
|
|
* @populate_pte_fn doesn't make any sense.
|
|
*
|
|
* @populate_pte_fn is used to populate the pagetable. NULL means the
|
|
* caller already populated the pagetable.
|
|
*
|
|
* RETURNS:
|
|
* The determined pcpu_unit_size which can be used to initialize
|
|
* percpu access.
|
|
*/
|
|
size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
|
|
size_t static_size,
|
|
ssize_t unit_size, ssize_t dyn_size,
|
|
void *base_addr,
|
|
pcpu_populate_pte_fn_t populate_pte_fn)
|
|
{
|
|
static struct vm_struct first_vm;
|
|
static int smap[2];
|
|
struct pcpu_chunk *schunk;
|
|
unsigned int cpu;
|
|
int nr_pages;
|
|
int err, i;
|
|
|
|
/* santiy checks */
|
|
BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC);
|
|
BUG_ON(!static_size);
|
|
if (unit_size >= 0) {
|
|
BUG_ON(unit_size < static_size +
|
|
(dyn_size >= 0 ? dyn_size : 0));
|
|
BUG_ON(unit_size & ~PAGE_MASK);
|
|
} else {
|
|
BUG_ON(dyn_size >= 0);
|
|
BUG_ON(base_addr);
|
|
}
|
|
BUG_ON(base_addr && populate_pte_fn);
|
|
|
|
if (unit_size >= 0)
|
|
pcpu_unit_pages = unit_size >> PAGE_SHIFT;
|
|
else
|
|
pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT,
|
|
PFN_UP(static_size));
|
|
|
|
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
|
|
pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
|
|
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
|
|
+ num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *);
|
|
|
|
if (dyn_size < 0)
|
|
dyn_size = pcpu_unit_size - static_size;
|
|
|
|
/*
|
|
* Allocate chunk slots. The additional last slot is for
|
|
* empty chunks.
|
|
*/
|
|
pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
|
|
pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
|
|
for (i = 0; i < pcpu_nr_slots; i++)
|
|
INIT_LIST_HEAD(&pcpu_slot[i]);
|
|
|
|
/* init static chunk */
|
|
schunk = alloc_bootmem(pcpu_chunk_struct_size);
|
|
INIT_LIST_HEAD(&schunk->list);
|
|
schunk->vm = &first_vm;
|
|
schunk->map = smap;
|
|
schunk->map_alloc = ARRAY_SIZE(smap);
|
|
schunk->page = schunk->page_ar;
|
|
schunk->free_size = dyn_size;
|
|
schunk->contig_hint = schunk->free_size;
|
|
|
|
schunk->map[schunk->map_used++] = -static_size;
|
|
if (schunk->free_size)
|
|
schunk->map[schunk->map_used++] = schunk->free_size;
|
|
|
|
/* allocate vm address */
|
|
first_vm.flags = VM_ALLOC;
|
|
first_vm.size = pcpu_chunk_size;
|
|
|
|
if (!base_addr)
|
|
vm_area_register_early(&first_vm, PAGE_SIZE);
|
|
else {
|
|
/*
|
|
* Pages already mapped. No need to remap into
|
|
* vmalloc area. In this case the static chunk can't
|
|
* be mapped or unmapped by percpu and is marked
|
|
* immutable.
|
|
*/
|
|
first_vm.addr = base_addr;
|
|
schunk->immutable = true;
|
|
}
|
|
|
|
/* assign pages */
|
|
nr_pages = -1;
|
|
for_each_possible_cpu(cpu) {
|
|
for (i = 0; i < pcpu_unit_pages; i++) {
|
|
struct page *page = get_page_fn(cpu, i);
|
|
|
|
if (!page)
|
|
break;
|
|
*pcpu_chunk_pagep(schunk, cpu, i) = page;
|
|
}
|
|
|
|
BUG_ON(i < PFN_UP(static_size));
|
|
|
|
if (nr_pages < 0)
|
|
nr_pages = i;
|
|
else
|
|
BUG_ON(nr_pages != i);
|
|
}
|
|
|
|
/* map them */
|
|
if (populate_pte_fn) {
|
|
for_each_possible_cpu(cpu)
|
|
for (i = 0; i < nr_pages; i++)
|
|
populate_pte_fn(pcpu_chunk_addr(schunk,
|
|
cpu, i));
|
|
|
|
err = pcpu_map(schunk, 0, nr_pages);
|
|
if (err)
|
|
panic("failed to setup static percpu area, err=%d\n",
|
|
err);
|
|
}
|
|
|
|
/* link the first chunk in */
|
|
pcpu_chunk_relocate(schunk, -1);
|
|
pcpu_chunk_addr_insert(schunk);
|
|
|
|
/* we're done */
|
|
pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0);
|
|
return pcpu_unit_size;
|
|
}
|