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[Qemu-devel] [PATCH for-3.0 3/9] migration: fix incorrect bitmap size ca
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH for-3.0 3/9] migration: fix incorrect bitmap size calculation |
Date: |
Thu, 5 Jul 2018 11:17:49 +0800 |
The calculation on size of received bitmap is incorrect for postcopy
recovery. Here we wanted to let the size to cover all the valid bits in
the bitmap, we should use DIV_ROUND_UP() instead of a division.
For example, a RAMBlock with size=4K (which contains only one single 4K
page) will have nbits=1, then nbits/8=0, then the real bitmap won't be
sent to source at all.
Signed-off-by: Peter Xu <address@hidden>
---
migration/ram.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index fbeb23f750..203c691ded 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -235,7 +235,7 @@ int64_t ramblock_recv_bitmap_send(QEMUFile *file,
bitmap_to_le(le_bitmap, block->receivedmap, nbits);
/* Size of the bitmap, in bytes */
- size = nbits / 8;
+ size = DIV_ROUND_UP(nbits, 8);
/*
* size is always aligned to 8 bytes for 64bit machines, but it
@@ -3944,7 +3944,7 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock
*block)
int ret = -EINVAL;
QEMUFile *file = s->rp_state.from_dst_file;
unsigned long *le_bitmap, nbits = block->used_length >> TARGET_PAGE_BITS;
- uint64_t local_size = nbits / 8;
+ uint64_t local_size = DIV_ROUND_UP(nbits, 8);
uint64_t size, end_mark;
trace_ram_dirty_bitmap_reload_begin(block->idstr);
--
2.17.1
- [Qemu-devel] [PATCH for-3.0 0/9] migration: postcopy recovery unit test, bug fixes, Peter Xu, 2018/07/04
- [Qemu-devel] [PATCH for-3.0 1/9] migration: simplify check to use qemu file buffer, Peter Xu, 2018/07/04
- [Qemu-devel] [PATCH for-3.0 2/9] migration: loosen recovery check when load vm, Peter Xu, 2018/07/04
- [Qemu-devel] [PATCH for-3.0 3/9] migration: fix incorrect bitmap size calculation,
Peter Xu <=
- [Qemu-devel] [PATCH for-3.0 4/9] tests: introduce migrate_postcopy_* helpers, Peter Xu, 2018/07/04
- Re: [Qemu-devel] [PATCH for-3.0 4/9] tests: introduce migrate_postcopy_* helpers, Dr. David Alan Gilbert, 2018/07/05
- Re: [Qemu-devel] [PATCH for-3.0 4/9] tests: introduce migrate_postcopy_* helpers, Juan Quintela, 2018/07/05
- [Qemu-devel] [PATCH for-3.0 5/9] tests: allow migrate() to take extra flags, Peter Xu, 2018/07/04