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The commit ade81479c7dd ("memcg: fix soft lockup in the OOM >> process") added the touch_softlockup_watchdog in the global OOM handler to >> suppess the soft lockup issues. However, while this change can suppress >> soft lockup warnings, it does not address RCU stalls, which can still be >> detected and may cause unnecessary disturbances. Simply remove the >> modification from the global OOM handler. >> >> Fixes: ade81479c7dd ("memcg: fix soft lockup in the OOM process") > > But this is not really fixing anything, is it? While this doesn't > address a potential RCU stall it doesn't address any actual problem. > So why do we want to do this? > [1] https://lore.kernel.org/cgroups/0d9ea655-5c1a-4ba9-9eeb-b45d74cc68d0@huaweicloud.com/ As previously discussed, the work I have done on the global OOM is 'half of the job'. Based on our discussions, I thought that it would be best to abandon this approach for global OOM. Therefore, I am sending this patch to revert the changes. Or just leave it? Best regards, Ridong >> Signed-off-by: Chen Ridong >> --- >> mm/oom_kill.c | 8 +------- >> 1 file changed, 1 insertion(+), 7 deletions(-) >> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c >> index 25923cfec9c6..2d8b27604ef8 100644 >> --- a/mm/oom_kill.c >> +++ b/mm/oom_kill.c >> @@ -44,7 +44,6 @@ >> #include >> #include >> #include >> -#include >> >> #include >> #include "internal.h" >> @@ -431,15 +430,10 @@ static void dump_tasks(struct oom_control *oc) >> mem_cgroup_scan_tasks(oc->memcg, dump_task, oc); >> else { >> struct task_struct *p; >> - int i = 0; >> >> rcu_read_lock(); >> - for_each_process(p) { >> - /* Avoid potential softlockup warning */ >> - if ((++i & 1023) == 0) >> - touch_softlockup_watchdog(); >> + for_each_process(p) >> dump_task(p, oc); >> - } >> rcu_read_unlock(); >> } >> } >> -- >> 2.34.1 >