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[Qemu-devel] [RFC v2 3/6] memory: use atomic ops for setting dirty memor
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [RFC v2 3/6] memory: use atomic ops for setting dirty memory bits |
Date: |
Tue, 2 Dec 2014 11:23:16 +0000 |
Use set_bit_atomic() and bitmap_set_atomic() so that multiple threads
can dirty memory without race conditions.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
I had to get creative to stay under 80 characters per line. I'm open to
suggestions if you prefer me to format it another way.
---
include/exec/ram_addr.h | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 8fc75cd..ba90daa 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -93,30 +93,32 @@ static inline void
cpu_physical_memory_set_dirty_flag(ram_addr_t addr,
unsigned client)
{
assert(client < DIRTY_MEMORY_NUM);
- set_bit(addr >> TARGET_PAGE_BITS, ram_list.dirty_memory[client]);
+ set_bit_atomic(addr >> TARGET_PAGE_BITS, ram_list.dirty_memory[client]);
}
static inline void cpu_physical_memory_set_dirty_range_nocode(ram_addr_t start,
ram_addr_t
length)
{
unsigned long end, page;
+ unsigned long **dirty_memory = ram_list.dirty_memory;
end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
page = start >> TARGET_PAGE_BITS;
- bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION], page, end -
page);
- bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_VGA], page, end - page);
+ bitmap_set_atomic(dirty_memory[DIRTY_MEMORY_MIGRATION], page, end - page);
+ bitmap_set_atomic(dirty_memory[DIRTY_MEMORY_VGA], page, end - page);
}
static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
ram_addr_t length)
{
unsigned long end, page;
+ unsigned long **dirty_memory = ram_list.dirty_memory;
end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
page = start >> TARGET_PAGE_BITS;
- bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION], page, end -
page);
- bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_VGA], page, end - page);
- bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_CODE], page, end - page);
+ bitmap_set_atomic(dirty_memory[DIRTY_MEMORY_MIGRATION], page, end - page);
+ bitmap_set_atomic(dirty_memory[DIRTY_MEMORY_VGA], page, end - page);
+ bitmap_set_atomic(dirty_memory[DIRTY_MEMORY_CODE], page, end - page);
xen_modified_memory(start, length);
}
@@ -142,10 +144,11 @@ static inline void
cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
for (k = 0; k < nr; k++) {
if (bitmap[k]) {
unsigned long temp = leul_to_cpu(bitmap[k]);
+ unsigned long **d = ram_list.dirty_memory;
- ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION][page + k] |=
temp;
- ram_list.dirty_memory[DIRTY_MEMORY_VGA][page + k] |= temp;
- ram_list.dirty_memory[DIRTY_MEMORY_CODE][page + k] |= temp;
+ atomic_or(&d[DIRTY_MEMORY_MIGRATION][page + k], temp);
+ atomic_or(&d[DIRTY_MEMORY_VGA][page + k], temp);
+ atomic_or(&d[DIRTY_MEMORY_CODE][page + k], temp);
}
}
xen_modified_memory(start, pages);
--
2.1.0
- [Qemu-devel] [RFC v2 0/6] memory: make dirty_memory[] accesses atomic, Stefan Hajnoczi, 2014/12/02
- [Qemu-devel] [RFC v2 1/6] bitmap: add atomic set functions, Stefan Hajnoczi, 2014/12/02
- [Qemu-devel] [RFC v2 2/6] bitmap: add atomic test and clear, Stefan Hajnoczi, 2014/12/02
- [Qemu-devel] [RFC v2 3/6] memory: use atomic ops for setting dirty memory bits,
Stefan Hajnoczi <=
- [Qemu-devel] [RFC v2 4/6] migration: move dirty bitmap sync to ram_addr.h, Stefan Hajnoczi, 2014/12/02
- [Qemu-devel] [RFC v2 5/6] memory: replace cpu_physical_memory_reset_dirty() with test-and-clear, Stefan Hajnoczi, 2014/12/02
- [Qemu-devel] [RFC v2 6/6] memory: make cpu_physical_memory_sync_dirty_bitmap() fully atomic, Stefan Hajnoczi, 2014/12/02