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[Qemu-devel] [PATCH 2/2] block/nfs: try to avoid the bounce buffer in pw
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCH 2/2] block/nfs: try to avoid the bounce buffer in pwritev |
Date: |
Fri, 17 Feb 2017 17:39:01 +0100 |
if the passed qiov contains exactly one iov we can
pass the buffer directly.
Signed-off-by: Peter Lieven <address@hidden>
---
block/nfs.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff --git a/block/nfs.c b/block/nfs.c
index ab5dcc2..bb4b75f 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -295,20 +295,27 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState
*bs, uint64_t offset,
NFSClient *client = bs->opaque;
NFSRPC task;
char *buf = NULL;
+ bool my_buffer = false;
nfs_co_init_task(bs, &task);
- buf = g_try_malloc(bytes);
- if (bytes && buf == NULL) {
- return -ENOMEM;
+ if (iov->niov != 1) {
+ buf = g_try_malloc(bytes);
+ if (bytes && buf == NULL) {
+ return -ENOMEM;
+ }
+ qemu_iovec_to_buf(iov, 0, buf, bytes);
+ my_buffer = true;
+ } else {
+ buf = iov->iov[0].iov_base;
}
- qemu_iovec_to_buf(iov, 0, buf, bytes);
-
if (nfs_pwrite_async(client->context, client->fh,
offset, bytes, buf,
nfs_co_generic_cb, &task) != 0) {
- g_free(buf);
+ if (my_buffer) {
+ g_free(buf);
+ }
return -ENOMEM;
}
@@ -317,7 +324,9 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState
*bs, uint64_t offset,
qemu_coroutine_yield();
}
- g_free(buf);
+ if (my_buffer) {
+ g_free(buf);
+ }
if (task.ret != bytes) {
return task.ret < 0 ? task.ret : -EIO;
--
1.9.1
[Qemu-devel] [PATCH 1/2] block/nfs: convert to preadv / pwritev, Peter Lieven, 2017/02/17
Re: [Qemu-devel] [PATCH 0/2] block/nfs optimizations, Jeff Cody, 2017/02/23