* Keqian Zhu (zhukeqi...@huawei.com) wrote:
> real_dirty_pages becomes equal to total ram size after dirty log sync
> in ram_init_bitmaps, the reason is that the bitmap of ramblock is
> initialized to be all set, so old path counts them as "real dirty" at
> beginning.
>
> This causes wrong dirty rate and false positive throttling at the end
> of first ram save iteration.
>
> Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
Since this function already returns num_dirty, why not just change the
caller to increment a counter based off the return value?
Can you point to the code which is using this value that triggers the
throttle?
Dave
> ---
> Changelog:
>
> v2:
> - use new_dirty_pages instead of accu_dirty_pages.
> - adjust commit messages.
>
> ---
> include/exec/ram_addr.h | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index 7b5c24e928..a95e2e7c25 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -443,7 +443,7 @@ static inline
> uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb,
> ram_addr_t start,
> ram_addr_t length,
> - uint64_t *real_dirty_pages)
> + uint64_t *new_dirty_pages)
> {
> ram_addr_t addr;
> unsigned long word = BIT_WORD((start + rb->offset) >> TARGET_PAGE_BITS);
> @@ -469,7 +469,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock
> *rb,
> 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;
> @@ -502,7 +501,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock
> *rb,
> start + addr + offset,
> 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++;
> @@ -511,6 +509,7 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock
> *rb,
> }
> }
>
> + *new_dirty_pages += num_dirty;
> return num_dirty;
> }
> #endif
> --
> 2.19.1
>
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
