* [Qemu-devel] [PATCH v2] sheepdog: do not blindly memset all read buffers
@ 2012-07-08 19:33 Christoph Hellwig
2012-07-09 8:27 ` [Qemu-devel] [sheepdog] " MORITA Kazutaka
0 siblings, 1 reply; 2+ messages in thread
From: Christoph Hellwig @ 2012-07-08 19:33 UTC (permalink / raw)
To: qemu-devel; +Cc: sheepdog
Only buffers that map to unallocated blocks need to be zeroed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/sheepdog.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)
Index: qemu/block/sheepdog.c
===================================================================
--- qemu.orig/block/sheepdog.c 2012-07-08 21:20:12.896597656 +0200
+++ qemu/block/sheepdog.c 2012-07-08 21:20:56.563264061 +0200
@@ -1556,18 +1556,26 @@ static int coroutine_fn sd_co_rw_vector(
len = MIN(total - done, SD_DATA_OBJ_SIZE - offset);
- if (!inode->data_vdi_id[idx]) {
- if (acb->aiocb_type == AIOCB_READ_UDATA) {
+ switch (acb->aiocb_type) {
+ case AIOCB_READ_UDATA:
+ if (!inode->data_vdi_id[idx]) {
+ qemu_iovec_memset_skip(acb->qiov, 0, len, done);
goto done;
}
-
- create = 1;
- } else if (acb->aiocb_type == AIOCB_WRITE_UDATA
- && !is_data_obj_writable(inode, idx)) {
- /* Copy-On-Write */
- create = 1;
- old_oid = oid;
- flags = SD_FLAG_CMD_COW;
+ break;
+ case AIOCB_WRITE_UDATA:
+ if (!inode->data_vdi_id[idx]) {
+ create = 1;
+ }
+ if (!is_data_obj_writable(inode, idx)) {
+ /* Copy-On-Write */
+ create = 1;
+ old_oid = oid;
+ flags = SD_FLAG_CMD_COW;
+ }
+ break;
+ default:
+ break;
}
if (create) {
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [sheepdog] [PATCH v2] sheepdog: do not blindly memset all read buffers
2012-07-08 19:33 [Qemu-devel] [PATCH v2] sheepdog: do not blindly memset all read buffers Christoph Hellwig
@ 2012-07-09 8:27 ` MORITA Kazutaka
0 siblings, 0 replies; 2+ messages in thread
From: MORITA Kazutaka @ 2012-07-09 8:27 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: sheepdog, qemu-devel
At Sun, 8 Jul 2012 21:33:16 +0200,
Christoph Hellwig wrote:
>
> Only buffers that map to unallocated blocks need to be zeroed.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> ---
> block/sheepdog.c | 28 ++++++++++++++++++----------
> 1 file changed, 18 insertions(+), 10 deletions(-)
>
> Index: qemu/block/sheepdog.c
> ===================================================================
> --- qemu.orig/block/sheepdog.c 2012-07-08 21:20:12.896597656 +0200
> +++ qemu/block/sheepdog.c 2012-07-08 21:20:56.563264061 +0200
> @@ -1556,18 +1556,26 @@ static int coroutine_fn sd_co_rw_vector(
>
> len = MIN(total - done, SD_DATA_OBJ_SIZE - offset);
>
> - if (!inode->data_vdi_id[idx]) {
> - if (acb->aiocb_type == AIOCB_READ_UDATA) {
> + switch (acb->aiocb_type) {
> + case AIOCB_READ_UDATA:
> + if (!inode->data_vdi_id[idx]) {
> + qemu_iovec_memset_skip(acb->qiov, 0, len, done);
> goto done;
> }
> -
> - create = 1;
> - } else if (acb->aiocb_type == AIOCB_WRITE_UDATA
> - && !is_data_obj_writable(inode, idx)) {
> - /* Copy-On-Write */
> - create = 1;
> - old_oid = oid;
> - flags = SD_FLAG_CMD_COW;
> + break;
> + case AIOCB_WRITE_UDATA:
> + if (!inode->data_vdi_id[idx]) {
> + create = 1;
> + }
> + if (!is_data_obj_writable(inode, idx)) {
> + /* Copy-On-Write */
> + create = 1;
> + old_oid = oid;
> + flags = SD_FLAG_CMD_COW;
> + }
> + break;
> + default:
> + break;
> }
>
> if (create) {
> --
There is no code to remove a blind memset from sd_co_readv, which
existed in the previous patch.
The others look good to me.
Thanks,
Kazutaka
^ permalink raw reply [flat|nested] 2+ messages in thread
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2012-07-09 8:27 ` [Qemu-devel] [sheepdog] " MORITA Kazutaka
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