diff options
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 109 |
1 files changed, 57 insertions, 52 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a42fa09ee91f..ae721a713bda 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3479,7 +3479,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct page *page = NULL; unsigned int alloc_flags; unsigned long did_some_progress; - enum migrate_mode migration_mode = MIGRATE_ASYNC; + enum migrate_mode migration_mode = MIGRATE_SYNC_LIGHT; enum compact_result compact_result; int compaction_retries = 0; int no_progress_loops = 0; @@ -3521,6 +3521,52 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, if (page) goto got_pg; + /* + * For costly allocations, try direct compaction first, as it's likely + * that we have enough base pages and don't need to reclaim. Don't try + * that for allocations that are allowed to ignore watermarks, as the + * ALLOC_NO_WATERMARKS attempt didn't yet happen. + */ + if (can_direct_reclaim && order > PAGE_ALLOC_COSTLY_ORDER && + !gfp_pfmemalloc_allowed(gfp_mask)) { + page = __alloc_pages_direct_compact(gfp_mask, order, + alloc_flags, ac, + MIGRATE_ASYNC, + &compact_result); + if (page) + goto got_pg; + + /* Checks for THP-specific high-order allocations */ + if (is_thp_gfp_mask(gfp_mask)) { + /* + * If compaction is deferred for high-order allocations, + * it is because sync compaction recently failed. If + * this is the case and the caller requested a THP + * allocation, we do not want to heavily disrupt the + * system, so we fail the allocation instead of entering + * direct reclaim. + */ + if (compact_result == COMPACT_DEFERRED) + goto nopage; + + /* + * Compaction is contended so rather back off than cause + * excessive stalls. + */ + if (compact_result == COMPACT_CONTENDED) + 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. All other requests should tolerate at + * least light sync migration. + */ + if (!(current->flags & PF_KTHREAD)) + migration_mode = MIGRATE_ASYNC; + } + } retry: /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ @@ -3575,55 +3621,33 @@ retry: if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL)) goto nopage; - /* - * Try direct compaction. The first pass is asynchronous. Subsequent - * attempts after direct reclaim are synchronous - */ + + /* Try direct reclaim and then allocating */ + page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac, + &did_some_progress); + if (page) + goto got_pg; + + /* Try direct compaction and then allocating */ page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, migration_mode, &compact_result); if (page) goto got_pg; - /* Checks for THP-specific high-order allocations */ - if (is_thp_gfp_mask(gfp_mask)) { - /* - * If compaction is deferred for high-order allocations, it is - * because sync compaction recently failed. If this is the case - * and the caller requested a THP allocation, we do not want - * to heavily disrupt the system, so we fail the allocation - * instead of entering direct reclaim. - */ - if (compact_result == COMPACT_DEFERRED) - goto nopage; - - /* - * Compaction is contended so rather back off than cause - * excessive stalls. - */ - if(compact_result == COMPACT_CONTENDED) - goto nopage; - } - 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, - &did_some_progress); - if (page) - goto got_pg; - /* Do not loop if specifically requested */ if (gfp_mask & __GFP_NORETRY) - goto noretry; + goto nopage; /* * Do not retry costly high order allocations unless they are * __GFP_REPEAT */ if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT)) - goto noretry; + goto nopage; /* * Costly allocations might have made a progress but this doesn't mean @@ -3662,25 +3686,6 @@ retry: goto 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. - * 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); - if (page) - goto got_pg; nopage: warn_alloc_failed(gfp_mask, order, NULL); got_pg: |