Messages in this thread |  | | | Date | Mon, 6 Jun 2011 14:38:51 +0200 | | From | Andrea Arcangeli <> | | Subject | Re: [PATCH] mm: compaction: Abort compaction if too many pages are isolated and caller is asynchronous |
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On Mon, Jun 06, 2011 at 11:39:24AM +0100, Mel Gorman wrote: > Well spotted. > > Acked-by: Mel Gorman <mgorman@suse.de> > > Minor nit. swapper_space is rarely referred to outside of the swap > code. Might it be more readable to use > > /* > * swapcache is accounted as NR_FILE_PAGES but it is not > * accounted as NR_SHMEM > * > if (PageSwapBacked(page) && !PageSwapCache(page))
I thought the comparison on swapper_space would be faster as it was immediate vs register in CPU, instead of forcing a memory access. Otherwise I would have used the above. Now the test_bit is written in C and lockless so it's not likely to be very different considering the cacheline is hot in the CPU but it's still referencing memory instead register vs immediate comparison.
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