On Tue, Dec 08, 2015 at 09:41:18AM +0900, Joonsoo Kim wrote: > On Mon, Dec 07, 2015 at 04:59:56PM +0800, Aaron Lu wrote: > > On Mon, Dec 07, 2015 at 04:35:24PM +0900, Joonsoo Kim wrote: > > > It looks like overhead still remain. I guess that migration scanner > > > would call pageblock_pfn_to_page() for more extended range so > > > overhead still remain. > > > > > > I have an idea to solve his problem. Aaron, could you test following patch > > > on top of base? It tries to skip calling pageblock_pfn_to_page() > > > > It doesn't apply on top of 25364a9e54fb8296837061bf684b76d20eec01fb > > cleanly, so I made some changes to make it apply and the result is: > > https://github.com/aaronlu/linux/commit/cb8d05829190b806ad3948ff9b9e08c8ba1daf63 > > Yes, that's okay. I made it on my working branch but it will not result in > any problem except applying. > > > > > There is a problem occured right after the test starts: > > [ 58.080962] BUG: unable to handle kernel paging request at ffffea0082000018 > > [ 58.089124] IP: [<ffffffff81193f29>] compaction_alloc+0xf9/0x270 > > [ 58.096109] PGD 107ffd6067 PUD 207f7d5067 PMD 0 > > [ 58.101569] Oops: 0000 [#1] SMP > > I did some mistake. Please test following patch. It is also made > on my working branch so you need to resolve conflict but it would be > trivial. > > I inserted some logs to check whether zone is contiguous or not. > Please check that normal zone is set to contiguous after testing. Yes it is contiguous, but unfortunately, the problem remains: [ 56.536930] check_zone_contiguous: Normal [ 56.543467] check_zone_contiguous: Normal: contiguous [ 56.549640] BUG: unable to handle kernel paging request at ffffea0082000018 [ 56.557717] IP: [<ffffffff81193f29>] compaction_alloc+0xf9/0x270 [ 56.564719] PGD 107ffd6067 PUD 207f7d5067 PMD 0 Full dmesg attached. Thanks, Aaron > > Thanks. > > ------>8------ > From 4a1a08d8ab3fb165b87ad2ec0a2000ff6892330f Mon Sep 17 00:00:00 2001 > From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > Date: Mon, 7 Dec 2015 14:51:42 +0900 > Subject: [PATCH] mm/compaction: Optimize pageblock_pfn_to_page() for > contiguous zone > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > --- > include/linux/mmzone.h | 1 + > mm/compaction.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 54 insertions(+), 1 deletion(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index e23a9e7..573f9a9 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -521,6 +521,7 @@ struct zone { > #endif > > #if defined CONFIG_COMPACTION || defined CONFIG_CMA > + int contiguous; > /* Set to true when the PG_migrate_skip bits should be cleared */ > bool compact_blockskip_flush; > #endif > diff --git a/mm/compaction.c b/mm/compaction.c > index 67b8d90..cb5c7a2 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -88,7 +88,7 @@ static inline bool migrate_async_suitable(int migratetype) > * the first and last page of a pageblock and avoid checking each individual > * page in a pageblock. > */ > -static struct page *pageblock_pfn_to_page(unsigned long start_pfn, > +static struct page *__pageblock_pfn_to_page(unsigned long start_pfn, > unsigned long end_pfn, struct zone *zone) > { > struct page *start_page; > @@ -114,6 +114,56 @@ static struct page *pageblock_pfn_to_page(unsigned long start_pfn, > return start_page; > } > > +static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn, > + unsigned long end_pfn, struct zone *zone) > +{ > + if (zone->contiguous == 1) > + return pfn_to_page(start_pfn); > + > + return __pageblock_pfn_to_page(start_pfn, end_pfn, zone); > +} > + > +static void check_zone_contiguous(struct zone *zone) > +{ > + unsigned long block_start_pfn = zone->zone_start_pfn; > + unsigned long block_end_pfn; > + unsigned long pfn; > + > + /* Already checked */ > + if (zone->contiguous) > + return; > + > + printk("%s: %s\n", __func__, zone->name); > + block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages); > + for (; block_start_pfn < zone_end_pfn(zone); > + block_start_pfn = block_end_pfn, > + block_end_pfn += pageblock_nr_pages) { > + > + block_end_pfn = min(block_end_pfn, zone_end_pfn(zone)); > + > + if (!__pageblock_pfn_to_page(block_start_pfn, > + block_end_pfn, zone)) { > + /* We have hole */ > + zone->contiguous = -1; > + printk("%s: %s: uncontiguous\n", __func__, zone->name); > + return; > + } > + > + /* Check validity of pfn within pageblock */ > + for (pfn = block_start_pfn; pfn < block_end_pfn; pfn++) { > + if (!pfn_valid_within(pfn)) { > + zone->contiguous = -1; > + printk("%s: %s: uncontiguous\n", __func__, zone->name); > + return; > + } > + } > + } > + > + /* We don't have hole */ > + zone->contiguous = 1; > + printk("%s: %s: contiguous\n", __func__, zone->name); > +} > + > #ifdef CONFIG_COMPACTION > > /* Do not skip compaction more than 64 times */ > @@ -1353,6 +1403,8 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) > ; > } > > + check_zone_contiguous(zone); > + > /* > * Clear pageblock skip if there were failures recently and compaction > * is about to be retried after being deferred. kswapd does not do > -- > 1.9.1 >
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