Messages in this thread | | | Date | Mon, 15 Jun 2015 09:59:47 -0400 | From | Rik van Riel <> | Subject | Re: [RFC 3/3] mm: make swapin readahead to improve thp collapse rate |
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On 06/14/2015 11:04 AM, Ebru Akagunduz wrote: > This patch makes swapin readahead to improve thp collapse rate. > When khugepaged scanned pages, there can be a few of the pages > in swap area. > > With the patch THP can collapse 4kB pages into a THP when > there are up to max_ptes_swap swap ptes in a 2MB range. > > The patch was tested with a test program that allocates > 800MB of memory, writes to it, and then sleeps. I force > the system to swap out all. Afterwards, the test program > touches the area by writing, it skips a page in each > 20 pages of the area. > > Without the patch, system did not swap in readahead. > THP rate was %47 of the program of the memory, it > did not change over time. > > With this patch, after 10 minutes of waiting khugepaged had > collapsed %99 of the program's memory. > > Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Mechanism looks good to me.
Acked-by: Rik van Riel <riel@redhat.com>
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