[Nbd] [akpm@...133...: [patch 081/109] nbd: increase default and max request sizes]
FYI -- the change was merged into the mainstream kernel today...
----- Forwarded message from akpm@...133... -----
Date: Tue, 30 Apr 2013 15:28:28 -0700
From: akpm@...133...
To: torvalds@...133...
Cc: akpm@...133..., belczyk@...1274..., axboe@...161..., paul.clements@...124...
Subject: [patch 081/109] nbd: increase default and max request sizes
From: Michal Belczyk <belczyk@...1274...>
Subject: 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.
The patch makes nbd network traffic more efficient by:
- reducing request fragmentation (4KB alignment)
- reducing the number of requests (fewer round trips, less network overhead)
Especially in high latency networks, larger request size can make a dramatic
Signed-off-by: Paul Clements <paul.clements@...124...>
Signed-off-by: Michal Belczyk <belczyk@...1274...>
Cc: Jens Axboe <axboe@...161...>
Signed-off-by: Andrew Morton <akpm@...133...>
---
drivers/block/nbd.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN drivers/block/nbd.c~nbd-increase-default-and-max-request-sizes drivers/block/nbd.c
--- a/drivers/block/nbd.c~nbd-increase-default-and-max-request-sizes
+++ a/drivers/block/nbd.c
@@ -856,6 +856,8 @@ static int __init nbd_init(void)
disk->queue->limits.discard_granularity = 512;
disk->queue->limits.max_discard_sectors = UINT_MAX;
disk->queue->limits.discard_zeroes_data = 0;
+ blk_queue_max_hw_sectors(disk->queue, 65536);
+ disk->queue->limits.max_sectors = 256;
}
if (register_blkdev(NBD_MAJOR, "nbd")) {
_
----- End forwarded message -----
--
Michal Belczyk Sr.
Reply to: