diff options
| -rw-r--r-- | include/linux/compaction.h | 5 | ||||
| -rw-r--r-- | mm/compaction.c | 52 | ||||
| -rw-r--r-- | mm/vmscan.c | 26 |
3 files changed, 45 insertions, 38 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 7bf0c521db63..173d9c07a895 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -95,7 +95,7 @@ extern enum compact_result try_to_compact_pages(gfp_t gfp_mask, struct page **page); extern void reset_isolation_suitable(pg_data_t *pgdat); extern bool compaction_suitable(struct zone *zone, int order, - int highest_zoneidx); + unsigned long watermark, int highest_zoneidx); extern void compaction_defer_reset(struct zone *zone, int order, bool alloc_success); @@ -113,7 +113,8 @@ static inline void reset_isolation_suitable(pg_data_t *pgdat) } static inline bool compaction_suitable(struct zone *zone, int order, - int highest_zoneidx) + unsigned long watermark, + int highest_zoneidx) { return false; } diff --git a/mm/compaction.c b/mm/compaction.c index 2e2d4db33e68..cf32e8053edb 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2381,40 +2381,42 @@ static enum compact_result compact_finished(struct compact_control *cc) } static bool __compaction_suitable(struct zone *zone, int order, - int highest_zoneidx, - unsigned long wmark_target) + unsigned long watermark, int highest_zoneidx, + unsigned long free_pages) { - unsigned long watermark; /* * Watermarks for order-0 must be met for compaction to be able to * isolate free pages for migration targets. This means that the - * watermark and alloc_flags have to match, or be more pessimistic than - * the check in __isolate_free_page(). We don't use the direct - * compactor's alloc_flags, as they are not relevant for freepage - * isolation. We however do use the direct compactor's highest_zoneidx - * to skip over zones where lowmem reserves would prevent allocation - * even if compaction succeeds. - * For costly orders, we require low watermark instead of min for - * compaction to proceed to increase its chances. + * watermark have to match, or be more pessimistic than the check in + * __isolate_free_page(). + * + * For costly orders, we require a higher watermark for compaction to + * proceed to increase its chances. + * + * We use the direct compactor's highest_zoneidx to skip over zones + * where lowmem reserves would prevent allocation even if compaction + * succeeds. + * * ALLOC_CMA is used, as pages in CMA pageblocks are considered - * suitable migration targets + * suitable migration targets. */ - watermark = (order > PAGE_ALLOC_COSTLY_ORDER) ? - low_wmark_pages(zone) : min_wmark_pages(zone); watermark += compact_gap(order); + if (order > PAGE_ALLOC_COSTLY_ORDER) + watermark += low_wmark_pages(zone) - min_wmark_pages(zone); return __zone_watermark_ok(zone, 0, watermark, highest_zoneidx, - ALLOC_CMA, wmark_target); + ALLOC_CMA, free_pages); } /* * compaction_suitable: Is this suitable to run compaction on this zone now? */ -bool compaction_suitable(struct zone *zone, int order, int highest_zoneidx) +bool compaction_suitable(struct zone *zone, int order, unsigned long watermark, + int highest_zoneidx) { enum compact_result compact_result; bool suitable; - suitable = __compaction_suitable(zone, order, highest_zoneidx, + suitable = __compaction_suitable(zone, order, watermark, highest_zoneidx, zone_page_state(zone, NR_FREE_PAGES)); /* * fragmentation index determines if allocation failures are due to @@ -2452,6 +2454,7 @@ bool compaction_suitable(struct zone *zone, int order, int highest_zoneidx) return suitable; } +/* Used by direct reclaimers */ bool compaction_zonelist_suitable(struct alloc_context *ac, int order, int alloc_flags) { @@ -2474,8 +2477,8 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order, */ available = zone_reclaimable_pages(zone) / order; available += zone_page_state_snapshot(zone, NR_FREE_PAGES); - if (__compaction_suitable(zone, order, ac->highest_zoneidx, - available)) + if (__compaction_suitable(zone, order, min_wmark_pages(zone), + ac->highest_zoneidx, available)) return true; } @@ -2512,13 +2515,13 @@ compaction_suit_allocation_order(struct zone *zone, unsigned int order, */ if (order > PAGE_ALLOC_COSTLY_ORDER && async && !(alloc_flags & ALLOC_CMA)) { - watermark = low_wmark_pages(zone) + compact_gap(order); - if (!__zone_watermark_ok(zone, 0, watermark, highest_zoneidx, - 0, zone_page_state(zone, NR_FREE_PAGES))) + if (!__zone_watermark_ok(zone, 0, watermark + compact_gap(order), + highest_zoneidx, 0, + zone_page_state(zone, NR_FREE_PAGES))) return COMPACT_SKIPPED; } - if (!compaction_suitable(zone, order, highest_zoneidx)) + if (!compaction_suitable(zone, order, watermark, highest_zoneidx)) return COMPACT_SKIPPED; return COMPACT_CONTINUE; @@ -3081,6 +3084,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) .mode = MIGRATE_SYNC_LIGHT, .ignore_skip_hint = false, .gfp_mask = GFP_KERNEL, + .alloc_flags = ALLOC_WMARK_MIN, }; enum compact_result ret; @@ -3099,7 +3103,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) continue; ret = compaction_suit_allocation_order(zone, - cc.order, zoneid, ALLOC_WMARK_MIN, + cc.order, zoneid, cc.alloc_flags, false); if (ret != COMPACT_CONTINUE) continue; diff --git a/mm/vmscan.c b/mm/vmscan.c index 2bc740637a6c..3370bdca6868 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -5890,12 +5890,15 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat, /* If compaction would go ahead or the allocation would succeed, stop */ for_each_managed_zone_pgdat(zone, pgdat, z, sc->reclaim_idx) { + unsigned long watermark = min_wmark_pages(zone); + /* Allocation can already succeed, nothing to do */ - if (zone_watermark_ok(zone, sc->order, min_wmark_pages(zone), + if (zone_watermark_ok(zone, sc->order, watermark, sc->reclaim_idx, 0)) return false; - if (compaction_suitable(zone, sc->order, sc->reclaim_idx)) + if (compaction_suitable(zone, sc->order, watermark, + sc->reclaim_idx)) return false; } @@ -6122,22 +6125,21 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc) sc->reclaim_idx, 0)) return true; - /* Compaction cannot yet proceed. Do reclaim. */ - if (!compaction_suitable(zone, sc->order, sc->reclaim_idx)) - return false; - /* - * Compaction is already possible, but it takes time to run and there - * are potentially other callers using the pages just freed. So proceed - * with reclaim to make a buffer of free pages available to give - * compaction a reasonable chance of completing and allocating the page. + * Direct reclaim usually targets the min watermark, but compaction + * takes time to run and there are potentially other callers using the + * pages just freed. So target a higher buffer to give compaction a + * reasonable chance of completing and allocating the pages. + * * Note that we won't actually reclaim the whole buffer in one attempt * as the target watermark in should_continue_reclaim() is lower. But if * we are already above the high+gap watermark, don't reclaim at all. */ - watermark = high_wmark_pages(zone) + compact_gap(sc->order); + watermark = high_wmark_pages(zone); + if (compaction_suitable(zone, sc->order, watermark, sc->reclaim_idx)) + return true; - return zone_watermark_ok_safe(zone, 0, watermark, sc->reclaim_idx); + return false; } static void consider_reclaim_throttle(pg_data_t *pgdat, struct scan_control *sc) |