On Wed, May 07 2014, Vlastimil Babka wrote: > The compaction free scanner in isolate_freepages() currently remembers PFN of > the highest pageblock where it successfully isolates, to be used as the > starting pageblock for the next invocation. The rationale behind this is that > page migration might return free pages to the allocator when migration fails > and we don't want to skip them if the compaction continues. > > Since migration now returns free pages back to compaction code where they can > be reused, this is no longer a concern. This patch changes isolate_freepages() > so that the PFN for restarting is updated with each pageblock where isolation > is attempted. Using stress-highalloc from mmtests, this resulted in 10% > reduction of the pages scanned by the free scanner. > > Note that the somewhat similar functionality that records highest successful > pageblock in zone->compact_cached_free_pfn, remains unchanged. This cache is > used when the whole compaction is restarted, not for multiple invocations of > the free scanner during single compaction. > > Signed-off-by: Vlastimil Babka <[email protected]> > Cc: Minchan Kim <[email protected]> > Cc: Mel Gorman <[email protected]> > Cc: Joonsoo Kim <[email protected]> > Cc: Bartlomiej Zolnierkiewicz <[email protected]> > Cc: Michal Nazarewicz <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]> > Cc: Naoya Horiguchi <[email protected]> > Cc: Christoph Lameter <[email protected]> > Cc: Rik van Riel <[email protected]> > --- > v2: no changes, just keep patches together > > mm/compaction.c | 18 ++++++------------ > 1 file changed, 6 insertions(+), 12 deletions(-) > -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +--<[email protected]>--<xmpp:[email protected]>--ooO--(_)--Ooo--
signature.asc
Description: PGP signature
