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[Qemu-devel] [PATCH 3/3] ram: RAMBlock->offset is always aligned to a wo
From: |
Wei Yang |
Subject: |
[Qemu-devel] [PATCH 3/3] ram: RAMBlock->offset is always aligned to a word |
Date: |
Tue, 30 Apr 2019 11:44:12 +0800 |
RAMBlock->offset is calculated by find_ram_offset, which makes sure the
offset is aligned to a word.
This patch removes the alignment check on offset and unnecessary
variable *word*.
Signed-off-by: Wei Yang <address@hidden>
---
include/exec/ram_addr.h | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 3dfb2d52fb..a7c81bdb32 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -413,18 +413,21 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock
*rb,
uint64_t *real_dirty_pages)
{
ram_addr_t addr;
- unsigned long word = BIT_WORD(rb->offset >> TARGET_PAGE_BITS);
uint64_t num_dirty = 0;
unsigned long *dest = rb->bmap;
- /* 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))) {
+ /*
+ * Since RAMBlock->offset is guaranteed to be aligned to a word by
+ * find_ram_offset(), if length is aligned at the start of a word, go the
+ * fast path.
+ */
+ if (!(length & ((BITS_PER_LONG << TARGET_PAGE_BITS) - 1))) {
int k;
int nr = BITS_TO_LONGS(length >> TARGET_PAGE_BITS);
unsigned long * const *src;
- unsigned long idx = (word * BITS_PER_LONG) / DIRTY_MEMORY_BLOCK_SIZE;
- unsigned long offset = BIT_WORD((word * BITS_PER_LONG) %
+ unsigned long idx = (rb->offset >> TARGET_PAGE_BITS) /
+ DIRTY_MEMORY_BLOCK_SIZE;
+ unsigned long offset = BIT_WORD((rb->offset >> TARGET_PAGE_BITS) %
DIRTY_MEMORY_BLOCK_SIZE);
rcu_read_lock();
--
2.19.1