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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: cl@linux.com, htejun@gmail.com
Cc: akpm@linux-foundation.org, mhocko@kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	hannes@cmpxchg.org, mgorman@suse.de
Subject: Re: [patch 3/3] vmstat: Create our own workqueue
Date: Wed, 28 Oct 2015 20:57:28 +0900	[thread overview]
Message-ID: <201510282057.JHI87536.OMOFFFLJOHQtVS@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <alpine.DEB.2.20.1510272202120.4647@east.gentwo.org>

Christoph Lameter wrote:
> On Wed, 28 Oct 2015, Tejun Heo wrote:
> 
> > The only thing necessary here is WQ_MEM_RECLAIM.  I don't see how
> > WQ_SYSFS and WQ_FREEZABLE make sense here.
> 
I can still trigger silent livelock with this patchset applied.

----------
[  272.283217] MemAlloc-Info: 9 stalling task, 0 dying task, 0 victim task.
[  272.285089] MemAlloc: a.out(11325) gfp=0x24280ca order=0 delay=19164
[  272.286817] MemAlloc: a.out(11326) gfp=0x242014a order=0 delay=19104
[  272.288512] MemAlloc: vmtoolsd(1897) gfp=0x242014a order=0 delay=19072
[  272.290280] MemAlloc: kworker/1:3(11286) gfp=0x2400000 order=0 delay=19056
[  272.292114] MemAlloc: sshd(11202) gfp=0x242014a order=0 delay=18927
[  272.293908] MemAlloc: tuned(2073) gfp=0x242014a order=0 delay=18799
[  272.297360] MemAlloc: nmbd(4752) gfp=0x242014a order=0 delay=16532
[  272.299115] MemAlloc: auditd(529) gfp=0x242014a order=0 delay=13073
[  272.302248] MemAlloc: irqbalance(1696) gfp=0x242014a order=0 delay=10529
(...snipped...)
[  272.851035] Showing busy workqueues and worker pools:
[  272.852583] workqueue events: flags=0x0
[  272.853942]   pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=1/256
[  272.855781]     pending: vmw_fb_dirty_flush [vmwgfx]
[  272.857500]   pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256
[  272.859359]     pending: vmpressure_work_fn
[  272.860840] workqueue events_freezable_power_: flags=0x84
[  272.862461]   pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256
[  272.864479]     in-flight: 11286:disk_events_workfn
[  272.866065]     pending: disk_events_workfn
[  272.867587] workqueue vmstat: flags=0x8
[  272.868942]   pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256
[  272.870785]     pending: vmstat_update
[  272.872248] pool 2: cpus=1 node=0 flags=0x0 nice=0 workers=4 idle: 14 218 43
----------

> 2. Create a separate workqueue so that the vmstat updater
>    is not blocked by other work requeusts. This creates a
>    new kernel thread <sigh> and avoids the issue of
>    differentials not folded in a timely fashion.

Did you really mean "the vmstat updater is not blocked by other
work requeusts"?

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  reply	other threads:[~2015-10-28 11:57 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-28  2:41 [patch 0/3] vmstat: Various enhancements Christoph Lameter
2015-10-28  2:41 ` [patch 1/3] vmstat: Make pageset processing optional in refresh_cpu_vm_stats Christoph Lameter
2015-10-28  2:41 ` [patch 2/3] vmstat: make vmstat_updater deferrable again and shut down on idle Christoph Lameter
2015-10-28  2:41 ` [patch 3/3] vmstat: Create our own workqueue Christoph Lameter
2015-10-28  2:43   ` Tejun Heo
2015-10-28  3:04     ` Christoph Lameter
2015-10-28 11:57       ` Tetsuo Handa [this message]
2015-10-28 22:32         ` Christoph Lameter
2015-10-29  2:24         ` Tejun Heo
2015-10-29  3:08           ` Tejun Heo
2015-10-30  1:01             ` Christoph Lameter
2015-10-31  1:15               ` Tejun Heo
2015-10-31  2:43               ` Tetsuo Handa
2015-11-02 16:12                 ` Christoph Lameter
2015-11-02 16:52                   ` Tetsuo Handa
2015-11-02 18:10                     ` Christoph Lameter
2015-11-02 19:11                       ` Tejun Heo
2015-11-06 11:28                   ` Tetsuo Handa
2015-11-06 12:56                     ` Christoph Lameter

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