Messages in this thread | | | Date | Tue, 04 Aug 2009 15:55:59 +0300 | From | Izik Eidus <> | Subject | Re: [PATCH 7/12] ksm: fix endless loop on oom |
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Hugh Dickins wrote: > break_ksm has been looping endlessly ignoring VM_FAULT_OOM: that should > only be a problem for ksmd when a memory control group imposes limits > (normally the OOM killer will kill others with an mm until it succeeds); > but in general (especially for MADV_UNMERGEABLE and KSM_RUN_UNMERGE) we > do need to route the error (or kill) back to the caller (or sighandling). > > Test signal_pending in unmerge_ksm_pages, which could be a lengthy > procedure if it has to spill into swap: returning -ERESTARTSYS so that > trivial signals will restart but fatals will terminate (is that right? > we do different things in different places in mm, none exactly this). > > unmerge_and_remove_all_rmap_items was forgetting to lock when going > down the mm_list: fix that. Whether it's successful or not, reset > ksm_scan cursor to head; but only if it's successful, reset seqnr > (shown in full_scans) - page counts will have gone down to zero. > > This patch leaves a significant OOM deadlock, but it's a good step > on the way, and that deadlock is fixed in a subsequent patch. > > Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> > --- > > > Better than before for sure, And I dont have in mind better and yet simple solution for the "failing to break the pages" then to just wait and catch them in the next scan, so ACK.
Acked-by: Izik Eidus <ieidus@redhat.com>
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