On Tue, Oct 09, 2012 at 01:08:30PM +0200, Bartlomiej Zolnierkiewicz wrote: > On Tuesday 09 October 2012 12:11:43 Mel Gorman wrote: > > On Tue, Oct 09, 2012 at 10:40:10AM +0200, Bartlomiej Zolnierkiewicz wrote: > > > I also need following patch to make CONFIG_CMA=y && CONFIG_COMPACTION=y > > > case > > > work: > > > > > > From: Bartlomiej Zolnierkiewicz <[email protected]> > > > Subject: [PATCH] mm: compaction: cache if a pageblock was scanned and no > > > pages were isolated - cma fix > > > > > > Patch "mm: compaction: cache if a pageblock was scanned and no pages > > > were isolated" needs a following fix to successfully boot next-20121002 > > > kernel (same with next-20121008) with CONFIG_CMA=y and CONFIG_COMPACTION=y > > > (with applied -fix1, -fix2, -fix3 patches from Mel Gorman and also with > > > cmatest module from Thierry Reding compiled in). > > > > > > > Why is it needed to make it boot? CMA should not care about the > > It boots without Thierry's cmatest module but then fails on CMA > allocation attempt (I used out-of-tree /dev/cma_test interface to > generate CMA allocation request from user-space). > > > PG_migrate_skip hint being set because it should always ignore it in > > alloc_contig_range() due to cc->ignore_skip_hint. It's not obvious to > > me why this fixes a boot failure and I wonder if it's papering over some > > underlying problem. Can you provide more details please? > > I just compared CONFIG_COMPACTION=n and =y cases initially, figured > out the difference and did the change. However on a closer look it > seems that {get,clear,set}_pageblock_skip() use incorrect bit ranges > (please compare to bit ranges used by {get,set}_pageblock_flags() > used for migration types) and can overwrite pageblock migratetype of > the next pageblock in the bitmap (I wonder how could this code ever > worked before?). > > > > Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]> > > > Signed-off-by: Kyungmin Park <[email protected]> > > > --- > > > mm/compaction.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > Index: b/mm/compaction.c > > > =================================================================== > > > --- a/mm/compaction.c 2012-10-08 18:10:53.491679716 +0200 > > > +++ b/mm/compaction.c 2012-10-08 18:11:33.615679713 +0200 > > > @@ -117,7 +117,8 @@ static void update_pageblock_skip(struct > > > bool migrate_scanner) > > > { > > > struct zone *zone = cc->zone; > > > - if (!page) > > > + > > > + if (!page || cc->ignore_skip_hint) > > > return; > > > > > > if (!nr_isolated) { > > The patch below also fixes the issue for me: > > From: Bartlomiej Zolnierkiewicz <[email protected]> > Subject: [PATCH] mm: compaction: fix bit ranges in > {get,clear,set}_pageblock_skip() > > {get,clear,set}_pageblock_skip() use incorrect bit ranges (please compare > to bit ranges used by {get,set}_pageblock_flags() used for migration types) > and can overwrite pageblock migratetype of the next pageblock in the bitmap. > > Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]> > Signed-off-by: Kyungmin Park <[email protected]> > --- > include/linux/pageblock-flags.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > Index: b/include/linux/pageblock-flags.h > =================================================================== > --- a/include/linux/pageblock-flags.h 2012-10-09 12:50:20.366340001 +0200 > +++ b/include/linux/pageblock-flags.h 2012-10-09 12:50:31.794339996 +0200 > @@ -71,13 +71,13 @@ void set_pageblock_flags_group(struct pa > #ifdef CONFIG_COMPACTION > #define get_pageblock_skip(page) \ > get_pageblock_flags_group(page, PB_migrate_skip, \ > - PB_migrate_skip + 1) > + PB_migrate_skip) > #define clear_pageblock_skip(page) \ > set_pageblock_flags_group(page, 0, PB_migrate_skip, \ > - PB_migrate_skip + 1) > + PB_migrate_skip) > #define set_pageblock_skip(page) \ > set_pageblock_flags_group(page, 1, PB_migrate_skip, \ > - PB_migrate_skip + 1) > + PB_migrate_skip) > #endif /* CONFIG_COMPACTION */ > > #define get_pageblock_flags(page) \
Tested-by: Thierry Reding <[email protected]>
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