* [Qemu-devel] [PATCH v4] sheepdog: do not blindly memset all read buffers
@ 2012-07-10 14:12 Christoph Hellwig
2012-07-10 18:06 ` MORITA Kazutaka
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2012-07-10 14:12 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 | 37 ++++++++++++++++++-------------------
1 file changed, 18 insertions(+), 19 deletions(-)
Index: qemu/block/sheepdog.c
===================================================================
--- qemu.orig/block/sheepdog.c 2012-07-10 15:46:51.433323624 +0200
+++ qemu/block/sheepdog.c 2012-07-10 15:47:59.329989886 +0200
@@ -1590,18 +1590,25 @@ 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(acb->qiov, done, 0, len);
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;
+ } else 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) {
@@ -1687,20 +1694,12 @@ static coroutine_fn int sd_co_readv(Bloc
int nb_sectors, QEMUIOVector *qiov)
{
SheepdogAIOCB *acb;
- int i, ret;
+ int ret;
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors, NULL, NULL);
acb->aiocb_type = AIOCB_READ_UDATA;
acb->aio_done_func = sd_finish_aiocb;
- /*
- * TODO: we can do better; we don't need to initialize
- * blindly.
- */
- for (i = 0; i < qiov->niov; i++) {
- memset(qiov->iov[i].iov_base, 0, qiov->iov[i].iov_len);
- }
-
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
qemu_aio_release(acb);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH v4] sheepdog: do not blindly memset all read buffers
2012-07-10 14:12 [Qemu-devel] [PATCH v4] sheepdog: do not blindly memset all read buffers Christoph Hellwig
@ 2012-07-10 18:06 ` MORITA Kazutaka
2012-07-11 13:01 ` Kevin Wolf
0 siblings, 1 reply; 3+ messages in thread
From: MORITA Kazutaka @ 2012-07-10 18:06 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Kevin Wolf, sheepdog, qemu-devel
At Tue, 10 Jul 2012 16:12:27 +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 | 37 ++++++++++++++++++-------------------
> 1 file changed, 18 insertions(+), 19 deletions(-)
Acked-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH v4] sheepdog: do not blindly memset all read buffers
2012-07-10 18:06 ` MORITA Kazutaka
@ 2012-07-11 13:01 ` Kevin Wolf
0 siblings, 0 replies; 3+ messages in thread
From: Kevin Wolf @ 2012-07-11 13:01 UTC (permalink / raw)
To: MORITA Kazutaka; +Cc: sheepdog, Christoph Hellwig, qemu-devel
Am 10.07.2012 20:06, schrieb MORITA Kazutaka:
> At Tue, 10 Jul 2012 16:12:27 +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 | 37 ++++++++++++++++++-------------------
>> 1 file changed, 18 insertions(+), 19 deletions(-)
>
> Acked-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Thanks, applied to the block branch.
Kevin
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-07-11 13:01 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-07-10 14:12 [Qemu-devel] [PATCH v4] sheepdog: do not blindly memset all read buffers Christoph Hellwig
2012-07-10 18:06 ` MORITA Kazutaka
2012-07-11 13:01 ` Kevin Wolf
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.