kernels 3.4 slower due to allocation workqueue

[Yann Dupont]

Le 15/04/2013 15:45, Mark Tinguely a écrit :
>
> Here are the allocation worker changes.
>

Hello mark,  thanks for you answer

> The biggest performance commit should be aa292847, which limits the 
> callers to the worker.
>
> commit 3b876c8f2a361ceeed3fed894980c69066f903a0
> Author: Jeff Liu <jeff.liu at oracle.com>
> Date:   Thu Jun 7 15:44:32 2012 +0800
>
>     xfs: fix debug_object WARN at xfs_alloc_vextent()
>
> commit aa292847b9fc6e187547110de833a7d3131bbddf
> Author: Dave Chinner <dchinner at redhat.com>
> Date:   Thu Jul 12 07:40:43 2012 +1000
>
>     xfs: don't defer metadata allocation to the workqueue
>

Only These 2 commits are candidates, the others are post 3.5.
I'll try to patch a 3.4 with each patch.

>  commit 2455881c0b52f87be539c4c7deab1afff4d8a560
> Author: Dave Chinner <dchinner at redhat.com>
> Date:   Fri Oct 5 11:06:58 2012 +1000
>
>     xfs: introduce XFS_BMAPI_STACK_SWITCH
>
> commit e04426b9202bccd4cfcbc70b2fa2aeca1c86d8f5
> Author: Dave Chinner <dchinner at redhat.com>
> Date:   Fri Oct 5 11:06:59 2012 +1000
>
>     xfs: move allocation stack switch up to xfs_bmapi_allocate
>
> commit 9e96fe6df44425b69ed89f6ac20352cec1f127d7
> Author: Brian Foster <bfoster at redhat.com>
> Date:   Thu Jan 17 13:11:29 2013 -0500
>
>     xfs: pull up stack_switch check into xfs_bmapi_write
>
>
> The last 3 patches address an AGF buffer hang with the allocation worker.
>
> --Mark.

As 3.4 Kernels don't have thoses patches, is there a risk associated 
with  3.4 kernels ?

Cheers,

-- 
Yann Dupont - Service IRTS, DSI Université de Nantes
Tel : 02.53.48.49.20 - Mail/Jabber : Yann.Dupont at univ-nantes.fr