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[Qemu-devel] [PATCH 14/15] nbd: support large NBD requests
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 14/15] nbd: support large NBD requests |
Date: |
Fri, 3 May 2013 13:52:51 +0200 |
The Linux nbd driver recently increased the maximum supported request
size up to 32 MB:
commit 078be02b80359a541928c899c2631f39628f56df
Author: Michal Belczyk <address@hidden>
Date: Tue Apr 30 15:28:28 2013 -0700
nbd: increase default and max request sizes
Raise the default max request size for nbd to 128KB (from 127KB) to get it
4KB aligned. This patch also allows the max request size to be increased
(via /sys/block/nbd<x>/queue/max_sectors_kb) to 32MB.
QEMU's 1 MB buffers are too small to handle these requests.
This patch allocates data buffers dynamically and allows up to 32 MB per
request.
Reported-by: Nick Thomas <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
include/block/nbd.h | 3 ++-
nbd.c | 17 +++++++++++------
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 0903d7a..c90f5e4 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -58,7 +58,8 @@ enum {
#define NBD_DEFAULT_PORT 10809
-#define NBD_BUFFER_SIZE (1024*1024)
+/* Maximum size of a single READ/WRITE data buffer */
+#define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
int tcp_socket_incoming(const char *address, uint16_t port);
diff --git a/nbd.c b/nbd.c
index 761f4ec..2606403 100644
--- a/nbd.c
+++ b/nbd.c
@@ -844,13 +844,11 @@ void nbd_client_close(NBDClient *client)
static NBDRequest *nbd_request_get(NBDClient *client)
{
NBDRequest *req;
- NBDExport *exp = client->exp;
assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
client->nb_requests++;
req = g_slice_new0(NBDRequest);
- req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
nbd_client_get(client);
req->client = client;
return req;
@@ -860,7 +858,9 @@ static void nbd_request_put(NBDRequest *req)
{
NBDClient *client = req->client;
- qemu_vfree(req->data);
+ if (req->data) {
+ qemu_vfree(req->data);
+ }
g_slice_free(NBDRequest, req);
if (client->nb_requests-- == MAX_NBD_REQUESTS) {
@@ -1007,6 +1007,7 @@ static ssize_t nbd_co_receive_request(NBDRequest *req,
struct nbd_request *reque
{
NBDClient *client = req->client;
int csock = client->sock;
+ uint32_t command;
ssize_t rc;
client->recv_coroutine = qemu_coroutine_self();
@@ -1018,9 +1019,9 @@ static ssize_t nbd_co_receive_request(NBDRequest *req,
struct nbd_request *reque
goto out;
}
- if (request->len > NBD_BUFFER_SIZE) {
+ if (request->len > NBD_MAX_BUFFER_SIZE) {
LOG("len (%u) is larger than max len (%u)",
- request->len, NBD_BUFFER_SIZE);
+ request->len, NBD_MAX_BUFFER_SIZE);
rc = -EINVAL;
goto out;
}
@@ -1034,7 +1035,11 @@ static ssize_t nbd_co_receive_request(NBDRequest *req,
struct nbd_request *reque
TRACE("Decoding type");
- if ((request->type & NBD_CMD_MASK_COMMAND) == NBD_CMD_WRITE) {
+ command = request->type & NBD_CMD_MASK_COMMAND;
+ if (command == NBD_CMD_READ || command == NBD_CMD_WRITE) {
+ req->data = qemu_blockalign(client->exp->bs, request->len);
+ }
+ if (command == NBD_CMD_WRITE) {
TRACE("Reading %u byte(s)", request->len);
if (qemu_co_recv(csock, req->data, request->len) != request->len) {
--
1.8.1.4
- [Qemu-devel] [PATCH 03/15] block: initial VHDX driver support framework - supports open and probe, (continued)
- [Qemu-devel] [PATCH 03/15] block: initial VHDX driver support framework - supports open and probe, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 05/15] blockdev: Replace "undefined error" in qmp_block_resize, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 06/15] vmdk: named return code., Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 07/15] vmdk: add support for “zeroed‐grain” GTE, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 08/15] vmdk: Add option to create zeroed-grain image, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 09/15] vmdk: change magic number to macro, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 10/15] vmdk: store fields of VmdkMetaData in cpu endian, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 11/15] vmdk: add bdrv_co_write_zeroes, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 12/15] qemu-iotests: Filter out vmdk creation options, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 13/15] nbd: use g_slice_new() instead of a freelist, Stefan Hajnoczi, 2013/05/03
- [Qemu-devel] [PATCH 14/15] nbd: support large NBD requests,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH 15/15] qemu-iotests: Filter out 'adapter_type', Stefan Hajnoczi, 2013/05/03