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exec: use memory_region_get_dirty_log_mask to optimize dirty tracking

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The memory API can now return the exact set of bitmaps that have to
be tracked.  Use it instead of the in_migration variable.

In the next patches, we will also use it to set only DIRTY_MEMORY_VGA
or DIRTY_MEMORY_MIGRATION if necessary.  This can make a difference
for dataplane, especially after the dirty bitmap is changed to use
more expensive atomic operations.

Of some interest is the change to stl_phys_notdirty.  When migration
was introduced, stl_phys_notdirty was changed to effectively behave
as stl_phys during migration.  In fact, if one looks at the function as it
was in the beginning (commit 8df1cd0, physical memory access functions,
2005-01-28), at the time the dirty bitmap was the equivalent of
DIRTY_MEMORY_CODE nowadays; hence, the function simply should not touch
the dirty code bits.  This patch changes it to do the intended thing.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2015-03-23 11:45:53 +01:00
parent 49dfcec403
commit 845b6214a3
1 changed files with 19 additions and 40 deletions
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59
exec.c
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@ -59,8 +59,6 @@
//#define DEBUG_SUBPAGE
#if !defined(CONFIG_USER_ONLY)
static bool in_migration;
/* ram_list is read under rcu_read_lock()/rcu_read_unlock(). Writes
* are protected by the ramlist lock.
*/
@ -866,11 +864,6 @@ void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t length,
}
}
static void cpu_physical_memory_set_dirty_tracking(bool enable)
{
in_migration = enable;
}
/* Called from RCU critical section */
hwaddr memory_region_section_get_iotlb(CPUState *cpu,
MemoryRegionSection *section,
@ -2161,22 +2154,6 @@ static void tcg_commit(MemoryListener *listener)
}
}
static void core_log_global_start(MemoryListener *listener)
{
cpu_physical_memory_set_dirty_tracking(true);
}
static void core_log_global_stop(MemoryListener *listener)
{
cpu_physical_memory_set_dirty_tracking(false);
}
static MemoryListener core_memory_listener = {
.log_global_start = core_log_global_start,
.log_global_stop = core_log_global_stop,
.priority = 1,
};
void address_space_init_dispatch(AddressSpace *as)
{
as->dispatch = NULL;
@ -2216,8 +2193,6 @@ static void memory_map_init(void)
memory_region_init_io(system_io, NULL, &unassigned_io_ops, NULL, "io",
65536);
address_space_init(&address_space_io, system_io, "I/O");
memory_listener_register(&core_memory_listener, &address_space_memory);
}
MemoryRegion *get_system_memory(void)
@ -2275,12 +2250,18 @@ int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
#else
static void invalidate_and_set_dirty(hwaddr addr,
static void invalidate_and_set_dirty(MemoryRegion *mr, hwaddr addr,
hwaddr length)
{
if (cpu_physical_memory_range_includes_clean(addr, length)) {
tb_invalidate_phys_range(addr, addr + length, 0);
cpu_physical_memory_set_dirty_range_nocode(addr, length);
uint8_t dirty_log_mask = memory_region_get_dirty_log_mask(mr);
if (dirty_log_mask & (1 << DIRTY_MEMORY_CODE)) {
tb_invalidate_phys_range(addr, addr + length, 0);
dirty_log_mask &= ~(1 << DIRTY_MEMORY_CODE);
}
if (dirty_log_mask) {
cpu_physical_memory_set_dirty_range_nocode(addr, length);
}
} else {
xen_modified_memory(addr, length);
}
@ -2368,7 +2349,7 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
/* RAM case */
ptr = qemu_get_ram_ptr(addr1);
memcpy(ptr, buf, l);
invalidate_and_set_dirty(addr1, l);
invalidate_and_set_dirty(mr, addr1, l);
}
} else {
if (!memory_access_is_direct(mr, is_write)) {
@ -2465,7 +2446,7 @@ static inline void cpu_physical_memory_write_rom_internal(AddressSpace *as,
switch (type) {
case WRITE_DATA:
memcpy(ptr, buf, l);
invalidate_and_set_dirty(addr1, l);
invalidate_and_set_dirty(mr, addr1, l);
break;
case FLUSH_CACHE:
flush_icache_range((uintptr_t)ptr, (uintptr_t)ptr + l);
@ -2690,7 +2671,7 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
mr = qemu_ram_addr_from_host(buffer, &addr1);
assert(mr != NULL);
if (is_write) {
invalidate_and_set_dirty(addr1, access_len);
invalidate_and_set_dirty(mr, addr1, access_len);
}
if (xen_enabled()) {
xen_invalidate_map_cache_entry(buffer);
@ -3019,6 +3000,7 @@ void address_space_stl_notdirty(AddressSpace *as, hwaddr addr, uint32_t val,
hwaddr l = 4;
hwaddr addr1;
MemTxResult r;
uint8_t dirty_log_mask;
rcu_read_lock();
mr = address_space_translate(as, addr, &addr1, &l,
@ -3030,13 +3012,10 @@ void address_space_stl_notdirty(AddressSpace *as, hwaddr addr, uint32_t val,
ptr = qemu_get_ram_ptr(addr1);
stl_p(ptr, val);
if (unlikely(in_migration)) {
if (cpu_physical_memory_is_clean(addr1)) {
/* invalidate code */
tb_invalidate_phys_page_range(addr1, addr1 + 4, 0);
/* set dirty bit */
cpu_physical_memory_set_dirty_range_nocode(addr1, 4);
}
dirty_log_mask = memory_region_get_dirty_log_mask(mr);
dirty_log_mask &= ~(1 << DIRTY_MEMORY_CODE);
if (dirty_log_mask) {
cpu_physical_memory_set_dirty_range_nocode(addr1, 4);
}
r = MEMTX_OK;
}
@ -3093,7 +3072,7 @@ static inline void address_space_stl_internal(AddressSpace *as,
stl_p(ptr, val);
break;
}
invalidate_and_set_dirty(addr1, 4);
invalidate_and_set_dirty(mr, addr1, 4);
r = MEMTX_OK;
}
if (result) {
@ -3197,7 +3176,7 @@ static inline void address_space_stw_internal(AddressSpace *as,
stw_p(ptr, val);
break;
}
invalidate_and_set_dirty(addr1, 2);
invalidate_and_set_dirty(mr, addr1, 2);
r = MEMTX_OK;
}
if (result) {