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Message-ID: <575ae411-08d8-7d92-105f-2d9574b3f542@huawei.com>
Date: Wed, 29 Sep 2021 20:38:39 +0800
From: Yongqiang Liu <liuyongqiang13@...wei.com>
To: <vincent.guittot@...aro.org>, <dietmar.eggemann@....com>,
<",sjenning"@redhat.com>, <xuyang2018.jy@...itsu.com>,
<",liwang"@redhat.com>
CC: <linux-kernel@...r.kernel.org>, <",linux-mm"@kvack.org>
Subject: [QUESTION] ltp: mavise06 failed when the task scheduled to another
cpu
Hi,
when runing this case in 5.10-lts kernel, it will trigger the folloing
failure:
......
madvise06.c:74: TINFO: memory.kmem.usage_in_bytes: 1752 Kb
madvise06.c:208: TPASS: more than 102400 Kb were moved to the swap
cache
madvise06.c:217: TINFO: PageFault(madvice / no mem access): 102401
madvise06.c:221: TINFO: PageFault(madvice / mem access): 102417
madvise06.c:82: TINFO: After page access
madvise06.c:84: TINFO: Swap: 307372 Kb
madvise06.c:86: TINFO: SwapCached: 101820 Kb
madvise06.c:88: TINFO: Cached: 103004Kb
madvise06.c:74: TINFO: memory.kmem.usage_in_bytes: 0Kb
madvise06.c:225: TFAIL: 16 pages were faulted out of 2 max
and we found that when we call the madvise the task was scheduled to
another cpu:
......
tst_res(TINFO, "before madvise MEMLIMIT CPU:%d", sched_getcpu());--->cpu0
TEST(madvise(target, MEM_LIMIT, MADV_WILLNEED));
tst_res(TINFO, "after madvise MEMLIMIT CPU:%d", sched_getcpu());--->cpu1
......
tst_res(TINFO, "before madvise PASS_THRESHOLDCPU:%d",
sched_getcpu());-->cpu1
TEST(madvise(target, PASS_THRESHOLD, MADV_WILLNEED));
tst_res(TINFO, "after madvise PASS_THRESHOLDCPU:%d", sched_getcpu());-->cpu0
.....
Is the PERCPU data swap_slot was not handled well?
with the following patch almost fix the error:
e9b9734b7465 sched/fair: Reduce cases for active balance
8a41dfcda7a3 sched/fair: Don't set LBF_ALL_PINNED unnecessarily
fc488ffd4297 sched/fair: Skip idle cfs_rq
but bind the task to a cpu also can solve this problem.
Kind regards,
Yongqiang Liu
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