Messages in this thread | | | Subject | Re: [PATCH 5/7] mm, vmscan: extract shrink_page_list reclaim counters into a struct | From | Vlastimil Babka <> | Date | Wed, 4 Jan 2017 15:51:43 +0100 |
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On 01/04/2017 11:19 AM, Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > shrink_page_list returns quite some counters back to its caller. Extract > the existing 5 into struct reclaim_stat because this makes the code > easier to follow and also allows further counters to be returned. > > While we are at it, make all of them unsigned rather than unsigned long > as we do not really need full 64b for them (we never scan more than > SWAP_CLUSTER_MAX pages at once). This should reduce some stack space. > > This patch shouldn't introduce any functional change.
[...]
> @@ -1266,11 +1270,13 @@ static unsigned long shrink_page_list(struct list_head *page_list, > list_splice(&ret_pages, page_list); > count_vm_events(PGACTIVATE, pgactivate); > > - *ret_nr_dirty += nr_dirty; > - *ret_nr_congested += nr_congested; > - *ret_nr_unqueued_dirty += nr_unqueued_dirty; > - *ret_nr_writeback += nr_writeback; > - *ret_nr_immediate += nr_immediate; > + if (stat) { > + stat->nr_dirty = nr_dirty; > + stat->nr_congested = nr_congested; > + stat->nr_unqueued_dirty = nr_unqueued_dirty; > + stat->nr_writeback = nr_writeback; > + stat->nr_immediate = nr_immediate; > + }
This change of '+=' to '=' raised my eybrows, but it seems both callers don't care so this is indeed no functional change and potentially faster.
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