Messages in this thread | | | From | Shakeel Butt <> | Date | Tue, 23 Nov 2021 09:59:11 -0800 | Subject | Re: [PATCH] mm: thp: update split_queue_len correctly |
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On Tue, Nov 23, 2021 at 9:47 AM Shakeel Butt <shakeelb@google.com> wrote: > > The deferred THPs are split on memory pressure through shrinker > callback and splitting of THP during reclaim can fail for several > reasons like unable to lock the THP, under writeback or unexpected > number of pins on the THP. Such pages are put back on the deferred split > list for consideration later. However kernel does not update the > deferred queue size on putting back the pages whose split was failed. > This patch fixes that.
I forgot to add the user visible impact.
"Without this patch the split_queue_len can underflow. Shrinker will always get that there are some THPs to split even if there are not and waste some cpu to scan the empty list."
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