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[Qemu-devel] [PATCH] block: change default for discard and write zeroes
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCH] block: change default for discard and write zeroes to INT_MAX |
Date: |
Mon, 2 Feb 2015 15:48:34 +0100 |
do not trim requests if the driver does not supply a limit
through BlockLimits. For write zeroes we still keep a limit
for the unsupported path to avoid allocating a big bounce buffer.
Suggested-by: Kevin Wolf <address@hidden>
Suggested-by: Denis V. Lunev <address@hidden>
Signed-off-by: Peter Lieven <address@hidden>
---
block.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/block.c b/block.c
index d45e4dd..ee7ff2c 100644
--- a/block.c
+++ b/block.c
@@ -3192,10 +3192,7 @@ int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState
*bs,
BDRV_REQ_COPY_ON_READ);
}
-/* if no limit is specified in the BlockLimits use a default
- * of 32768 512-byte sectors (16 MiB) per request.
- */
-#define MAX_WRITE_ZEROES_DEFAULT 32768
+#define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768
static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
@@ -3206,7 +3203,7 @@ static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState *bs,
int ret = 0;
int max_write_zeroes = bs->bl.max_write_zeroes ?
- bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT;
+ bs->bl.max_write_zeroes : INT_MAX;
while (nb_sectors > 0 && !ret) {
int num = nb_sectors;
@@ -3242,7 +3239,7 @@ static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState *bs,
if (ret == -ENOTSUP) {
/* Fall back to bounce buffer if write zeroes is unsupported */
int max_xfer_len = MIN_NON_ZERO(bs->bl.max_transfer_length,
- MAX_WRITE_ZEROES_DEFAULT);
+ MAX_WRITE_ZEROES_BOUNCE_BUFFER);
num = MIN(num, max_xfer_len);
iov.iov_len = num * BDRV_SECTOR_SIZE;
if (iov.iov_base == NULL) {
@@ -5097,11 +5094,6 @@ static void coroutine_fn bdrv_discard_co_entry(void
*opaque)
rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors);
}
-/* if no limit is specified in the BlockLimits use a default
- * of 32768 512-byte sectors (16 MiB) per request.
- */
-#define MAX_DISCARD_DEFAULT 32768
-
int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
int nb_sectors)
{
@@ -5126,7 +5118,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs,
int64_t sector_num,
return 0;
}
- max_discard = bs->bl.max_discard ? bs->bl.max_discard :
MAX_DISCARD_DEFAULT;
+ max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
while (nb_sectors > 0) {
int ret;
int num = nb_sectors;
--
1.9.1
- [Qemu-devel] [PATCH] block: change default for discard and write zeroes to INT_MAX,
Peter Lieven <=
[Qemu-devel] [PATCH 1/2] glusterfs: fix max_discard, Denis V. Lunev, 2015/02/02