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Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memo
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memory_sync_dirty_bitmap is always 0 |
Date: |
Tue, 14 May 2019 15:21:08 +0100 |
User-agent: |
Mutt/1.11.4 (2019-03-13) |
* Wei Yang (address@hidden) wrote:
> Since start of cpu_physical_memory_sync_dirty_bitmap is always 0, we can
> remove this parameter and simplify the calculation a bit.
>
> Signed-off-by: Wei Yang <address@hidden>
So I think you're right it's currently unused; however, lets ask
Paolo: Do we need to keep this parameter for flexiblity?
Dave
> ---
> include/exec/ram_addr.h | 15 ++++++---------
> migration/ram.c | 2 +-
> 2 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index 9ecd911c3e..3dfb2d52fb 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -409,18 +409,16 @@ static inline void
> cpu_physical_memory_clear_dirty_range(ram_addr_t start,
>
> 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)
> {
> ram_addr_t addr;
> - unsigned long word = BIT_WORD((start + rb->offset) >> TARGET_PAGE_BITS);
> + unsigned long word = BIT_WORD(rb->offset >> TARGET_PAGE_BITS);
> uint64_t num_dirty = 0;
> unsigned long *dest = rb->bmap;
>
> - /* start address and length is aligned at the start of a word? */
> - if (((word * BITS_PER_LONG) << TARGET_PAGE_BITS) ==
> - (start + rb->offset) &&
> + /* offset and length is aligned at the start of a word? */
> + if (((word * BITS_PER_LONG) << TARGET_PAGE_BITS) == (rb->offset) &&
> !(length & ((BITS_PER_LONG << TARGET_PAGE_BITS) - 1))) {
> int k;
> int nr = BITS_TO_LONGS(length >> TARGET_PAGE_BITS);
> @@ -428,14 +426,13 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock
> *rb,
> unsigned long idx = (word * BITS_PER_LONG) / DIRTY_MEMORY_BLOCK_SIZE;
> unsigned long offset = BIT_WORD((word * BITS_PER_LONG) %
> DIRTY_MEMORY_BLOCK_SIZE);
> - unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
>
> rcu_read_lock();
>
> src = atomic_rcu_read(
> &ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION])->blocks;
>
> - for (k = page; k < page + nr; k++) {
> + for (k = 0; k < nr; k++) {
> if (src[idx][offset]) {
> unsigned long bits = atomic_xchg(&src[idx][offset], 0);
> unsigned long new_dirty;
> @@ -458,11 +455,11 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock
> *rb,
>
> for (addr = 0; addr < length; addr += TARGET_PAGE_SIZE) {
> if (cpu_physical_memory_test_and_clear_dirty(
> - start + addr + offset,
> + addr + offset,
> TARGET_PAGE_SIZE,
> DIRTY_MEMORY_MIGRATION)) {
> *real_dirty_pages += 1;
> - long k = (start + addr) >> TARGET_PAGE_BITS;
> + long k = addr >> TARGET_PAGE_BITS;
> if (!test_and_set_bit(k, dest)) {
> num_dirty++;
> }
> diff --git a/migration/ram.c b/migration/ram.c
> index 9948b2d021..1def8122e9 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1646,7 +1646,7 @@ static void migration_bitmap_sync_range(RAMState *rs,
> RAMBlock *rb,
> ram_addr_t length)
> {
> rs->migration_dirty_pages +=
> - cpu_physical_memory_sync_dirty_bitmap(rb, 0, length,
> + cpu_physical_memory_sync_dirty_bitmap(rb, length,
> &rs->num_dirty_pages_period);
> }
>
> --
> 2.19.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memory_sync_dirty_bitmap is always 0,
Dr. David Alan Gilbert <=