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From:   Qian Cai <cai@lca.pw>
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Subject: Re: [PATCH] mm/vmstat: Reduce zone lock hold time when reading /proc/pagetypeinfo
Date:   Thu, 24 Oct 2019 00:34:41 -0400
Message-Id: <15BA6C88-21C1-4BF3-BB10-2A207AEBB401@lca.pw>
References: <20191024033313.GA42124@shbuild999.sh.intel.com>
Cc:     Waiman Long <longman@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>, Roman Gushchin <guro@fb.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Jann Horn <jannh@google.com>, Song Liu <songliubraving@fb.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rafael Aquini <aquini@redhat.com>
In-Reply-To: <20191024033313.GA42124@shbuild999.sh.intel.com>
To:     Feng Tang <feng.tang@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


> On Oct 23, 2019, at 11:33 PM, Feng Tang <feng.tang@intel.com> wrote:
>=20
> We have been using the /proc/pagetypeinfo for debugging, mainly for
> client platforms like phones/tablets. We met problems like very slow
> system response or OOM things, and many of them could be related with
> memory pressure or fragmentation issues, where monitoring /proc/pagetypein=
fo
> will be very useful for debugging.

This description of use case is rather vague. Which part of the information i=
n that file is critical to debug an OOM or slow system that is not readily a=
vailable in places like /proc/zoneinfo, /proc/buddyinfo, sysrq-m, or OOM tra=
ce etc?=