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protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH v3] memcg: fix soft lockup in the OOM process MIME-Version: 1.0 Hello. On Tue, Dec 24, 2024 at 02:52:38AM +0000, Chen Ridong wrote: > A soft lockup issue was found in the product with about 56,000 tasks were > in the OOM cgroup, it was traversing them when the soft lockup was > triggered. Why is this softlockup a problem?=20 It's lot of tasks afterall and possibly a slow console (given looking for a victim among the comparable number didn't trigger it). > To fix this issue, call 'cond_resched' in the 'mem_cgroup_scan_tasks' > function per 1000 iterations. For global OOM, call > 'touch_softlockup_watchdog' per 1000 iterations to avoid this issue. This only hides the issue. It could be similarly fixed by simply decreasing loglevel=3D ;-) cond_resched() in the memcg case may be OK but the arbitrary touch for global situation may hide possibly useful troubleshooting information. (Yeah, cond_resched() won't fit inside RCU section as in other global task iterations.) 0.02=E2=82=AC, Michal --rcupueyfrbzf4mc7 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTd6mfF2PbEZnpdoAkt3Wney77BSQUCZ3gN3QAKCRAt3Wney77B Sa6zAQC54Sd7KuanLbmfLaGOXxG7G6FlPC6aPzF++JEaooFm7gEA8z9Hl5K+ruKY SyVpErXNAh4+caqnmTT99iRdkx6hdAE= =DTHm -----END PGP SIGNATURE----- --rcupueyfrbzf4mc7--