From: Michal Hocko <mhocko@suse.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: yuwang668899@gmail.com, vbabka@suse.cz, mpatocka@redhat.com,
hannes@cmpxchg.org, mgorman@suse.de, dave.hansen@intel.com,
akpm@linux-foundation.org, linux-mm@kvack.org,
chenggang.qcg@alibaba-inc.com, yuwang.yuwang@alibaba-inc.com
Subject: Re: [PATCH] mm,page_alloc: softlockup on warn_alloc on
Date: Fri, 15 Sep 2017 14:00:20 +0200 [thread overview]
Message-ID: <20170915120020.diakzyzsx73ygnfx@dhcp22.suse.cz> (raw)
In-Reply-To: <201709152038.BHF26323.LFOMFHOFOJSVQt@I-love.SAKURA.ne.jp>
On Fri 15-09-17 20:38:49, Tetsuo Handa wrote:
[...]
> You said "identify _why_ we see the lockup trigerring in the first
> place" without providing means to identify it. Unless you provide
> means to identify it (in a form which can be immediately and easily
> backported to 4.9 kernels; that is, backporting not-yet-accepted
> printk() offloading patchset is not a choice), this patch cannot be
> refused.
I fail to see why. It simply workarounds an existing problem elsewhere
in the kernel without deeper understanding on where the problem is. You
can add your own instrumentation to debug and describe the problem. This
is no different to any other kernel bugs...
If our printk implementation is so weak it cannot cope with writers then
that should be fixed without spreading hacks in different subsystems. If
the lockup is a real problem under normal workloads (rather than
artificial ones) then we should try to throttle more aggresively.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-09-15 12:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-15 9:58 [PATCH] mm,page_alloc: softlockup on warn_alloc on wang Yu
2017-09-15 10:39 ` Michal Hocko
2017-09-15 11:38 ` Tetsuo Handa
2017-09-15 12:00 ` Michal Hocko [this message]
2017-09-15 12:09 ` Tetsuo Handa
2017-09-15 12:14 ` Michal Hocko
2017-09-15 14:12 ` Tetsuo Handa
2017-09-15 14:23 ` Michal Hocko
2017-09-24 1:56 ` Tetsuo Handa
2017-09-15 14:37 ` Johannes Weiner
2017-09-15 15:23 ` Tetsuo Handa
2017-09-15 18:44 ` Johannes Weiner
2017-09-16 0:25 ` Tetsuo Handa
2017-09-18 6:05 ` Michal Hocko
2017-09-18 6:31 ` Tetsuo Handa
2017-09-18 6:43 ` Michal Hocko
2017-09-16 4:12 ` Tetsuo Handa
2017-10-11 11:14 ` Tetsuo Handa
2017-10-18 10:54 ` Tetsuo Handa
2017-09-18 6:03 ` Michal Hocko
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