Messages in this thread | | | Date | Tue, 12 Feb 2019 12:56:35 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] proc, oom: do not report alien mms when setting oom_score_adj |
| |
On Tue, 12 Feb 2019 11:21:29 +0100 Michal Hocko <mhocko@kernel.org> wrote:
> Tetsuo has reported that creating a thousands of processes sharing MM > without SIGHAND (aka alien threads) and setting > /proc/<pid>/oom_score_adj will swamp the kernel log and takes ages [1] > to finish. This is especially worrisome that all that printing is done > under RCU lock and this can potentially trigger RCU stall or softlockup > detector. > > The primary reason for the printk was to catch potential users who might > depend on the behavior prior to 44a70adec910 ("mm, oom_adj: make sure > processes sharing mm have same view of oom_score_adj") but after more > than 2 years without a single report I guess it is safe to simply remove > the printk altogether. > > The next step should be moving oom_score_adj over to the mm struct and > remove all the tasks crawling as suggested by [2] > > [1] http://lkml.kernel.org/r/97fce864-6f75-bca5-14bc-12c9f890e740@i-love.sakura.ne.jp > [2] http://lkml.kernel.org/r/20190117155159.GA4087@dhcp22.suse.cz
I think I'll put a cc:stable on this. Deleting a might-trigger debug printk is safe and welcome.
| |