From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id DADA26B000C for ; Sun, 22 Jul 2018 20:02:41 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id b7-v6so13587838qtp.14 for ; Sun, 22 Jul 2018 17:02:41 -0700 (PDT) Received: from o2.20qt.s2shared.sendgrid.net (o2.20qt.s2shared.sendgrid.net. [167.89.106.65]) by mx.google.com with ESMTPS id x1-v6si4817610qtx.173.2018.07.22.17.02.40 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 22 Jul 2018 17:02:41 -0700 (PDT) Subject: Re: [Bug 200627] New: Stutters and high kernel CPU usage from list_lru_count_one when cache fills memory From: Kevin Liu References: <20180722164034.62bf461029073a21e591b8c3@linux-foundation.org> <5166980c-210e-2e68-974a-9115e5c72543@potatofrom.space> Message-ID: <63e10f4d-ad8f-8d02-2f78-caf01eaa72c1@potatofrom.space> Date: Mon, 23 Jul 2018 00:02:40 +0000 (UTC) Mime-Version: 1.0 In-Reply-To: <5166980c-210e-2e68-974a-9115e5c72543@potatofrom.space> Content-type: multipart/alternative; boundary="----------=_1532304160-1805-2648" Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: bugzilla-daemon@bugzilla.kernel.org, linux-mm@kvack.org This is a multi-part message in MIME format... ------------=_1532304160-1805-2648 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sorry, not sure if the previous message registered on bugzilla due to the pgp signature? Including it below. On 07/22/2018 07:44 PM, Kevin Liu wrote: >> How recently? Were earlier kernels better behaved? > I've seen this issue both on Linux 4.16.15 (admittedly using the -ck > patchset) and on vanilla Linux 4.18-rc4 (which is what I'm currently using). > > I'm fairly certain that it did not occur on Linux 4.14.50, which I used > previously, but I will boot back into it to double-check and let you know. > And yes, booted back into Linux 4.14.54, there appears to be no issue -- list_lru_count_one reaches 6% overhead at most: Overhead Shared Object Symbol 5.91% [kernel] [k] list_lru_count_one 5.13% [kernel] [k] nmi 4.08% [kernel] [k] read_hpet 1.26% zma [.] Zone::CheckAlarms 1.16% [kernel] [k] _raw_spin_lock 1.07% restic [.] 0x00000000002e696c 1.06% .perf-wrapped [.] hpp__sort_overhead ------------=_1532304160-1805-2648 Content-Type: text/html; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 7bit

Sorry, not sure if the previous message registered on bugzilla due to the pgp signature? Including it below.

On 07/22/2018 07:44 PM, Kevin Liu wrote:

How recently? Were earlier kernels better behaved?

I've seen this issue both on Linux 4.16.15 (admittedly using the -ck
patchset) and on vanilla Linux 4.18-rc4 (which is what I'm currently using).

I'm fairly certain that it did not occur on Linux 4.14.50, which I used
previously, but I will boot back into it to double-check and let you know.

And yes, booted back into Linux 4.14.54, there appears to be no issue — list_lru_count_one reaches 6% overhead at most:

Overhead Shared Object Symbol

5.91%  [kernel]                          [k] list_lru_count_one

5.13%  [kernel]                          [k] nmi

4.08%  [kernel]                          [k] read_hpet

1.26%  zma                               [.] Zone::CheckAlarms

1.16%  [kernel]                          [k] _raw_spin_lock

1.07%  restic                            [.] 0x00000000002e696c

1.06%  .perf-wrapped                     [.] hpp__sort_overhead

------------=_1532304160-1805-2648--