Commit 1ffb5dfd authored by Chao Fan's avatar Chao Fan Committed by Juan Quintela
Browse files

Change the method to calculate dirty-pages-rate 



In function cpu_physical_memory_sync_dirty_bitmap, file
include/exec/ram_addr.h:

if (src[idx][offset]) {
    unsigned long bits = atomic_xchg(&src[idx][offset], 0);
    unsigned long new_dirty;
    new_dirty = ~dest[k];
    dest[k] |= bits;
    new_dirty &= bits;
    num_dirty += ctpopl(new_dirty);
}

After these codes executed, only the pages not dirtied in bitmap(dest),
but dirtied in dirty_memory[DIRTY_MEMORY_MIGRATION] will be calculated.
For example:
When ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] = 0b00001111,
and atomic_rcu_read(&migration_bitmap_rcu)->bmap = 0b00000011,
the new_dirty will be 0b00001100, and this function will return 2 but not
4 which is expected.
the dirty pages in dirty_memory[DIRTY_MEMORY_MIGRATION] are all new,
so these should be calculated also.

Signed-off-by: default avatarChao Fan <fanc.fnst@cn.fujitsu.com>
Signed-off-by: default avatarLi Zhijian <lizhijian@cn.fujitsu.com>
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent 1883ff34

include/exec/ram_addr.h

+4 −1
Original line number Diff line number Diff line
@@ -355,7 +355,8 @@ static inline void cpu_physical_memory_clear_dirty_range(ram_addr_t start, 
static inline

uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,

                                               ram_addr_t start,

                                               ram_addr_t length)

                                               ram_addr_t length,

                                               int64_t *real_dirty_pages)

{

    ram_addr_t addr;

    unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
@@ -379,6 +380,7 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest, 
            if (src[idx][offset]) {

                unsigned long bits = atomic_xchg(&src[idx][offset], 0);

                unsigned long new_dirty;

                *real_dirty_pages += ctpopl(bits);

                new_dirty = ~dest[k];

                dest[k] |= bits;

                new_dirty &= bits;
@@ -398,6 +400,7 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest, 
                        start + addr,

                        TARGET_PAGE_SIZE,

                        DIRTY_MEMORY_MIGRATION)) {

                *real_dirty_pages += 1;

                long k = (start + addr) >> TARGET_PAGE_BITS;

                if (!test_and_set_bit(k, dest)) {

                    num_dirty++;

migration/ram.c

+5 −7
Original line number Diff line number Diff line
@@ -576,18 +576,18 @@ static inline bool migration_bitmap_clear_dirty(ram_addr_t addr) 
    return ret;

}



static int64_t num_dirty_pages_period;

static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length)

{

    unsigned long *bitmap;

    bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;

    migration_dirty_pages +=

        cpu_physical_memory_sync_dirty_bitmap(bitmap, start, length);

    migration_dirty_pages += cpu_physical_memory_sync_dirty_bitmap(bitmap,

                             start, length, &num_dirty_pages_period);

}



/* Fix me: there are too many global variables used in migration process. */

static int64_t start_time;

static int64_t bytes_xfer_prev;

static int64_t num_dirty_pages_period;

static uint64_t xbzrle_cache_miss_prev;

static uint64_t iterations_prev;
@@ -620,7 +620,6 @@ uint64_t ram_pagesize_summary(void) 
static void migration_bitmap_sync(void)

{

    RAMBlock *block;

    uint64_t num_dirty_pages_init = migration_dirty_pages;

    MigrationState *s = migrate_get_current();

    int64_t end_time;

    int64_t bytes_xfer_now;
@@ -646,9 +645,8 @@ static void migration_bitmap_sync(void) 
    rcu_read_unlock();

    qemu_mutex_unlock(&migration_bitmap_mutex);



    trace_migration_bitmap_sync_end(migration_dirty_pages

                                    - num_dirty_pages_init);

    num_dirty_pages_period += migration_dirty_pages - num_dirty_pages_init;

    trace_migration_bitmap_sync_end(num_dirty_pages_period);



    end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);



    /* more than 1 second = 1000 millisecons */