diff options
| -rw-r--r-- | mm/page_alloc.c | 88 |
1 files changed, 78 insertions, 10 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f51c302..38ad6dd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3180,6 +3180,13 @@ out: return page; } + +/* + * Maximum number of compaction retries wit a progress before OOM + * killer is consider as the only way to move forward. + */ +#define MAX_COMPACT_RETRIES 16 + #ifdef CONFIG_COMPACTION /* Try memory compaction for high-order allocations before reclaim */ static struct page * @@ -3247,14 +3254,60 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, return NULL; } + +static inline bool +should_compact_retry(unsigned int order, enum compact_result compact_result, + enum migrate_mode *migrate_mode, + int compaction_retries) +{ + if (!order) + return false; + + /* + * compaction considers all the zone as desperately out of memory + * so it doesn't really make much sense to retry except when the + * failure could be caused by weak migration mode. + */ + if (compaction_failed(compact_result)) { + if (*migrate_mode == MIGRATE_ASYNC) { + *migrate_mode = MIGRATE_SYNC_LIGHT; + return true; + } + return false; + } + + /* + * !costly allocations are really important and we have to make sure + * the compaction wasn't deferred or didn't bail out early due to locks + * contention before we go OOM. Still cap the reclaim retry loops with + * progress to prevent from looping forever and potential trashing. + */ + if (order <= PAGE_ALLOC_COSTLY_ORDER) { + if (compaction_withdrawn(compact_result)) + return true; + if (compaction_retries <= MAX_COMPACT_RETRIES) + return true; + } + + return false; +} #else static inline struct page * __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, enum migrate_mode mode, enum compact_result *compact_result) { + *compact_result = COMPACT_SKIPPED; return NULL; } + +static inline bool +should_compact_retry(unsigned int order, enum compact_result compact_result, + enum migrate_mode *migrate_mode, + int compaction_retries) +{ + return false; +} #endif /* CONFIG_COMPACTION */ /* Perform direct synchronous page reclaim */ @@ -3501,6 +3554,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, unsigned long did_some_progress; enum migrate_mode migration_mode = MIGRATE_ASYNC; enum compact_result compact_result; + int compaction_retries = 0; int no_progress_loops = 0; /* @@ -3612,13 +3666,8 @@ retry: goto nopage; } - /* - * It can become very expensive to allocate transparent hugepages at - * fault, so use asynchronous memory compaction for THP unless it is - * khugepaged trying to collapse. - */ - if (!is_thp_gfp_mask(gfp_mask) || (current->flags & PF_KTHREAD)) - migration_mode = MIGRATE_SYNC_LIGHT; + if (order && compaction_made_progress(compact_result)) + compaction_retries++; /* Try direct reclaim and then allocating */ page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac, @@ -3649,6 +3698,17 @@ retry: no_progress_loops)) goto retry; + /* + * It doesn't make any sense to retry for the compaction if the order-0 + * reclaim is not able to make any progress because the current + * implementation of the compaction depends on the sufficient amount + * of free memory (see __compaction_suitable) + */ + if (did_some_progress > 0 && + should_compact_retry(order, compact_result, + &migration_mode, compaction_retries)) + goto retry; + /* Reclaim has failed us, start killing things */ page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); if (page) @@ -3662,10 +3722,18 @@ retry: noretry: /* - * High-order allocations do not necessarily loop after - * direct reclaim and reclaim/compaction depends on compaction - * being called after reclaim so call directly if necessary + * High-order allocations do not necessarily loop after direct reclaim + * and reclaim/compaction depends on compaction being called after + * reclaim so call directly if necessary. + * It can become very expensive to allocate transparent hugepages at + * fault, so use asynchronous memory compaction for THP unless it is + * khugepaged trying to collapse. All other requests should tolerate + * at least light sync migration. */ + if (is_thp_gfp_mask(gfp_mask) && !(current->flags & PF_KTHREAD)) + migration_mode = MIGRATE_ASYNC; + else + migration_mode = MIGRATE_SYNC_LIGHT; page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, migration_mode, &compact_result); |
