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[PATCH v5 08/10] Reduce the PVM stop time during Checkpoint
From: |
leirao |
Subject: |
[PATCH v5 08/10] Reduce the PVM stop time during Checkpoint |
Date: |
Thu, 1 Apr 2021 15:47:27 +0800 |
From: "Rao, Lei" <lei.rao@intel.com>
When flushing memory from ram cache to ram during every checkpoint
on secondary VM, we can copy continuous chunks of memory instead of
4096 bytes per time to reduce the time of VM stop during checkpoint.
Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
migration/ram.c | 48 +++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 45 insertions(+), 3 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index c69a8e0..317fa4e 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -822,6 +822,41 @@ unsigned long migration_bitmap_find_dirty(RAMState *rs,
RAMBlock *rb,
return next;
}
+/*
+ * colo_bitmap_find_diry:find contiguous dirty pages from start
+ *
+ * Returns the page offset within memory region of the start of the contiguout
+ * dirty page
+ *
+ * @rs: current RAM state
+ * @rb: RAMBlock where to search for dirty pages
+ * @start: page where we start the search
+ * @num: the number of contiguous dirty pages
+ */
+static inline
+unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
+ unsigned long start, unsigned long *num)
+{
+ unsigned long size = rb->used_length >> TARGET_PAGE_BITS;
+ unsigned long *bitmap = rb->bmap;
+ unsigned long first, next;
+
+ *num = 0;
+
+ if (ramblock_is_ignored(rb)) {
+ return size;
+ }
+
+ first = find_next_bit(bitmap, size, start);
+ if (first >= size) {
+ return first;
+ }
+ next = find_next_zero_bit(bitmap, size, first + 1);
+ assert(next >= first);
+ *num = next - first;
+ return first;
+}
+
static inline bool migration_bitmap_clear_dirty(RAMState *rs,
RAMBlock *rb,
unsigned long page)
@@ -3679,19 +3714,26 @@ void colo_flush_ram_cache(void)
block = QLIST_FIRST_RCU(&ram_list.blocks);
while (block) {
- offset = migration_bitmap_find_dirty(ram_state, block, offset);
+ unsigned long num = 0;
+ offset = colo_bitmap_find_dirty(ram_state, block, offset, &num);
if (((ram_addr_t)offset) << TARGET_PAGE_BITS
>= block->used_length) {
offset = 0;
+ num = 0;
block = QLIST_NEXT_RCU(block, next);
} else {
- migration_bitmap_clear_dirty(ram_state, block, offset);
+ unsigned long i = 0;
+
+ for (i = 0; i < num; i++) {
+ migration_bitmap_clear_dirty(ram_state, block, offset + i);
+ }
dst_host = block->host
+ (((ram_addr_t)offset) << TARGET_PAGE_BITS);
src_host = block->colo_cache
+ (((ram_addr_t)offset) << TARGET_PAGE_BITS);
- memcpy(dst_host, src_host, TARGET_PAGE_SIZE);
+ memcpy(dst_host, src_host, TARGET_PAGE_SIZE * num);
+ offset += num;
}
}
}
--
1.8.3.1
- RE: [PATCH v5 01/10] Remove some duplicate trace code., (continued)
- [PATCH v5 03/10] Optimize the function of filter_send, leirao, 2021/04/01
- [PATCH v5 04/10] Remove migrate_set_block_enabled in checkpoint, leirao, 2021/04/01
- [PATCH v5 05/10] Add a function named packet_new_nocopy for COLO., leirao, 2021/04/01
- [PATCH v5 06/10] Add the function of colo_compare_cleanup, leirao, 2021/04/01
- [PATCH v5 07/10] Reset the auto-converge counter at every checkpoint., leirao, 2021/04/01
- [PATCH v5 08/10] Reduce the PVM stop time during Checkpoint,
leirao <=
- [PATCH v5 09/10] Add the function of colo_bitmap_clear_dirty, leirao, 2021/04/01
- [PATCH v5 10/10] Fixed calculation error of pkt->header_size in fill_pkt_tcp_info(), leirao, 2021/04/01
- Re: [PATCH v5 00/10] Fixed some bugs and optimized some codes for COLO, Lukas Straub, 2021/04/04