d73415a315
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:
$ CC=clang CXX=clang++ ./configure ... && make
../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.
This patch was generated using:
$ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
sort -u >/tmp/changed_identifiers
$ for identifier in $(</tmp/changed_identifiers); do
sed -i "s%\<$identifier\>%q$identifier%g" \
$(git grep -I -l "\<$identifier\>")
done
I manually fixed line-wrap issues and misaligned rST tables.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
81 lines
2.8 KiB
C
81 lines
2.8 KiB
C
#ifndef RAMLIST_H
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#define RAMLIST_H
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#include "qemu/queue.h"
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#include "qemu/thread.h"
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#include "qemu/rcu.h"
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#include "qemu/rcu_queue.h"
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typedef struct RAMBlockNotifier RAMBlockNotifier;
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#define DIRTY_MEMORY_VGA 0
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#define DIRTY_MEMORY_CODE 1
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#define DIRTY_MEMORY_MIGRATION 2
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#define DIRTY_MEMORY_NUM 3 /* num of dirty bits */
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/* The dirty memory bitmap is split into fixed-size blocks to allow growth
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* under RCU. The bitmap for a block can be accessed as follows:
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*
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* rcu_read_lock();
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*
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* DirtyMemoryBlocks *blocks =
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* qatomic_rcu_read(&ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION]);
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*
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* ram_addr_t idx = (addr >> TARGET_PAGE_BITS) / DIRTY_MEMORY_BLOCK_SIZE;
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* unsigned long *block = blocks.blocks[idx];
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* ...access block bitmap...
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*
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* rcu_read_unlock();
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*
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* Remember to check for the end of the block when accessing a range of
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* addresses. Move on to the next block if you reach the end.
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*
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* Organization into blocks allows dirty memory to grow (but not shrink) under
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* RCU. When adding new RAMBlocks requires the dirty memory to grow, a new
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* DirtyMemoryBlocks array is allocated with pointers to existing blocks kept
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* the same. Other threads can safely access existing blocks while dirty
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* memory is being grown. When no threads are using the old DirtyMemoryBlocks
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* anymore it is freed by RCU (but the underlying blocks stay because they are
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* pointed to from the new DirtyMemoryBlocks).
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*/
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#define DIRTY_MEMORY_BLOCK_SIZE ((ram_addr_t)256 * 1024 * 8)
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typedef struct {
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struct rcu_head rcu;
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unsigned long *blocks[];
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} DirtyMemoryBlocks;
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typedef struct RAMList {
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QemuMutex mutex;
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RAMBlock *mru_block;
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/* RCU-enabled, writes protected by the ramlist lock. */
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QLIST_HEAD(, RAMBlock) blocks;
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DirtyMemoryBlocks *dirty_memory[DIRTY_MEMORY_NUM];
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uint32_t version;
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QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers;
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} RAMList;
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extern RAMList ram_list;
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/* Should be holding either ram_list.mutex, or the RCU lock. */
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#define INTERNAL_RAMBLOCK_FOREACH(block) \
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QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
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/* Never use the INTERNAL_ version except for defining other macros */
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#define RAMBLOCK_FOREACH(block) INTERNAL_RAMBLOCK_FOREACH(block)
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void qemu_mutex_lock_ramlist(void);
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void qemu_mutex_unlock_ramlist(void);
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struct RAMBlockNotifier {
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void (*ram_block_added)(RAMBlockNotifier *n, void *host, size_t size);
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void (*ram_block_removed)(RAMBlockNotifier *n, void *host, size_t size);
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QLIST_ENTRY(RAMBlockNotifier) next;
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};
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void ram_block_notifier_add(RAMBlockNotifier *n);
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void ram_block_notifier_remove(RAMBlockNotifier *n);
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void ram_block_notify_add(void *host, size_t size);
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void ram_block_notify_remove(void *host, size_t size);
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void ram_block_dump(Monitor *mon);
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#endif /* RAMLIST_H */
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