On 14.4.2015 21:54, Andrew Morton wrote: > On Tue, 14 Apr 2015 14:53:45 +0800 kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > >> tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >> head: b79013b2449c23f1f505bdf39c5a6c330338b244 >> commit: f8224aa5a0a4627926019bba7511926393fbee3b mm, compaction: do not recheck suitable_migration_target under lock >> date: 6 months ago >> config: x86_64-randconfig-ib0-04141359 (attached as .config) >> reproduce: >> git checkout f8224aa5a0a4627926019bba7511926393fbee3b >> # save the attached .config to linux build tree >> make ARCH=x86_64 >> >> All warnings: >> >>>> mm/compaction.c:250:13: warning: 'suitable_migration_target' defined but not used [-Wunused-function] >> static bool suitable_migration_target(struct page *page) >> ^ > > Easy enough - it only has one callsite. This sounded familiar, and sure enough I found patch from January https://lkml.org/lkml/2015/1/13/589 That was v2 after I suggested a subjectively better placement of the function when v1 placed it as your patch IIRC. But whatever. > > --- a/mm/compaction.c~mm-compactionc-fix-suitable_migration_target-unused-warning > +++ a/mm/compaction.c > @@ -391,28 +391,6 @@ static inline bool compact_should_abort( > return false; > } > > -/* Returns true if the page is within a block suitable for migration to */ > -static bool suitable_migration_target(struct page *page) > -{ > - /* If the page is a large free page, then disallow migration */ > - if (PageBuddy(page)) { > - /* > - * We are checking page_order without zone->lock taken. But > - * the only small danger is that we skip a potentially suitable > - * pageblock, so it's not worth to check order for valid range. > - */ > - if (page_order_unsafe(page) >= pageblock_order) > - return false; > - } > - > - /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */ > - if (migrate_async_suitable(get_pageblock_migratetype(page))) > - return true; > - > - /* Otherwise skip the block */ > - return false; > -} > - > /* > * Isolate free pages onto a private freelist. If @strict is true, will abort > * returning 0 on any invalid PFNs or non-free pages inside of the pageblock > @@ -896,6 +874,29 @@ isolate_migratepages_range(struct compac > > #endif /* CONFIG_COMPACTION || CONFIG_CMA */ > #ifdef CONFIG_COMPACTION > + > +/* Returns true if the page is within a block suitable for migration to */ > +static bool suitable_migration_target(struct page *page) > +{ > + /* If the page is a large free page, then disallow migration */ > + if (PageBuddy(page)) { > + /* > + * We are checking page_order without zone->lock taken. But > + * the only small danger is that we skip a potentially suitable > + * pageblock, so it's not worth to check order for valid range. > + */ > + if (page_order_unsafe(page) >= pageblock_order) > + return false; > + } > + > + /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */ > + if (migrate_async_suitable(get_pageblock_migratetype(page))) > + return true; > + > + /* Otherwise skip the block */ > + return false; > +} > + > /* > * Based on information in the current compact_control, find blocks > * suitable for isolating free pages from and then isolate them. > _ > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>