linux-kernel - Re: [RESEND PATCH] xen/blkfront: increase the default value of xen_blkif_max

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <54BF7BE4.2080005@citrix.com>
Date:	Wed, 21 Jan 2015 11:13:56 +0100
From:	Roger Pau Monné <roger.pau@...rix.com>
To:	Bob Liu <bob.liu@...cle.com>, <xen-devel@...ts.xen.org>
CC:	<david.vrabel@...rix.com>, <linux-kernel@...r.kernel.org>,
	<konrad.wilk@...cle.com>
Subject: Re: [RESEND PATCH] xen/blkfront: increase the default value of xen_blkif_max_segments

El 21/01/15 a les 8.56, Bob Liu ha escrit:
> The default max-segments of indirect requests was 32, so IO operations with
> bigger block size(>32*4k) would be split and make performance drop.
> 
> Nowadays backend device usually support 512k max_sectors_kb on desktop,
> and usually larger on server machines connected with high-end storage system.
> The default max size(128k) is not appropriate anymore, this patch increases it
> to 128(128*4k=512k).
> 
> Signed-off-by: Bob Liu <bob.liu@...cle.com>

Looks fine to me, the Linux backend is also prepared to handle it
without any modifications. As I said in the last version, I would add
the following to the commit message:

This change implies we can now have 32*128+32 = 4128 in-flight grants,
which greatly surpasses the default amount of persistent grants blkback
can handle, so the LRU in blkback will kick in.

Roger.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/