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[Qemu-devel] [PULL v3 04/38] block: do not allocate an iovec per read of
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL v3 04/38] block: do not allocate an iovec per read of a growable/zero_after_eof BDS |
Date: |
Tue, 13 Jan 2015 13:47:42 +0000 |
From: Paolo Bonzini <address@hidden>
Most reads do not go past the end of the file, and they can use the
input QEMUIOVector instead of creating one. This removes the
qemu_iovec_* functions from the profile.
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/block.c b/block.c
index 4165d42..58f8042 100644
--- a/block.c
+++ b/block.c
@@ -3034,18 +3034,16 @@ static int coroutine_fn
bdrv_aligned_preadv(BlockDriverState *bs,
max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num),
align >> BDRV_SECTOR_BITS);
- if (max_nb_sectors > 0) {
+ if (nb_sectors < max_nb_sectors) {
+ ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+ } else if (max_nb_sectors > 0) {
QEMUIOVector local_qiov;
- size_t local_sectors;
-
- max_nb_sectors = MIN(max_nb_sectors, SIZE_MAX / BDRV_SECTOR_BITS);
- local_sectors = MIN(max_nb_sectors, nb_sectors);
qemu_iovec_init(&local_qiov, qiov->niov);
qemu_iovec_concat(&local_qiov, qiov, 0,
- local_sectors * BDRV_SECTOR_SIZE);
+ max_nb_sectors * BDRV_SECTOR_SIZE);
- ret = drv->bdrv_co_readv(bs, sector_num, local_sectors,
+ ret = drv->bdrv_co_readv(bs, sector_num, max_nb_sectors,
&local_qiov);
qemu_iovec_destroy(&local_qiov);
--
2.1.0
- [Qemu-devel] [PULL v3 00/38] Block patches, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 02/38] qemu-iotests: Speed up make check-block, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 01/38] qemu-iotests: Remove 091 from quick group, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 05/38] block: replace g_new0 with g_new for bottom half allocation., Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 03/38] block: mark AioContext as recursive, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 06/38] checkpatch: Brace handling on multi-line condition, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 04/38] block: do not allocate an iovec per read of a growable/zero_after_eof BDS,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL v3 07/38] block: Get full backing filename from string, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 09/38] block: Relative backing file for image creation, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 10/38] block/vmdk: Relative backing file for creation, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 08/38] block: JSON filenames and relative backing files, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 13/38] block: fix spoiling all dirty bitmaps by mirror and migration, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 11/38] iotests: Add test for relative backing file names, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 14/38] qapi: Comment version info in TransactionAction, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 12/38] qapi: Fix document for BlockStats.node-name, Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 15/38] qmp: Add command 'blockdev-backup', Stefan Hajnoczi, 2015/01/13
- [Qemu-devel] [PULL v3 16/38] block: Add blockdev-backup to transaction, Stefan Hajnoczi, 2015/01/13