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Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memo
From: |
Wei Yang |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memory_sync_dirty_bitmap is always 0 |
Date: |
Wed, 17 Jul 2019 09:13:37 +0800 |
User-agent: |
Mutt/1.9.4 (2018-02-28) |
On Tue, May 14, 2019 at 03:21:08PM +0100, Dr. David Alan Gilbert wrote:
>* 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?
>
Hey, Paolo
Do you have some spare time to give some insight?
>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
--
Wei Yang
Help you, Help me
- Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memory_sync_dirty_bitmap is always 0,
Wei Yang <=