diff options
| -rw-r--r-- | mm/compaction.c | 10 | ||||
| -rw-r--r-- | mm/internal.h | 1 | ||||
| -rw-r--r-- | mm/vmscan.c | 147 |
3 files changed, 54 insertions, 104 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 5b2bfbaa821a..ccf97b02b85f 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1191,11 +1191,11 @@ static int __compact_finished(struct zone *zone, struct compact_control *cc, /* * Mark that the PG_migrate_skip information should be cleared - * by kswapd when it goes to sleep. kswapd does not set the + * by kswapd when it goes to sleep. kcompactd does not set the * flag itself as the decision to be clear should be directly * based on an allocation request. */ - if (!current_is_kswapd()) + if (cc->direct_compaction) zone->compact_blockskip_flush = true; return COMPACT_COMPLETE; @@ -1338,10 +1338,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) /* * Clear pageblock skip if there were failures recently and compaction - * is about to be retried after being deferred. kswapd does not do - * this reset as it'll reset the cached information when going to sleep. + * is about to be retried after being deferred. */ - if (compaction_restarting(zone, cc->order) && !current_is_kswapd()) + if (compaction_restarting(zone, cc->order)) __reset_isolation_suitable(zone); /* @@ -1477,6 +1476,7 @@ static unsigned long compact_zone_order(struct zone *zone, int order, .mode = mode, .alloc_flags = alloc_flags, .classzone_idx = classzone_idx, + .direct_compaction = true, }; INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); diff --git a/mm/internal.h b/mm/internal.h index b95952c2faec..4042a8a05672 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -172,6 +172,7 @@ struct compact_control { unsigned long last_migrated_pfn;/* Not yet flushed page being freed */ enum migrate_mode mode; /* Async or sync migration mode */ bool ignore_skip_hint; /* Scan blocks even if marked skip */ + bool direct_compaction; /* False from kcompactd or /proc/... */ int order; /* order a direct compactor needs */ const gfp_t gfp_mask; /* gfp mask of a direct compactor */ const int alloc_flags; /* alloc flags of a direct compactor */ diff --git a/mm/vmscan.c b/mm/vmscan.c index 5dcc71140108..f87cfaa955a8 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2968,18 +2968,23 @@ static void age_active_anon(struct zone *zone, struct scan_control *sc) } while (memcg); } -static bool zone_balanced(struct zone *zone, int order, - unsigned long balance_gap, int classzone_idx) +static bool zone_balanced(struct zone *zone, int order, bool highorder, + unsigned long balance_gap, int classzone_idx) { - if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone) + - balance_gap, classzone_idx)) - return false; + unsigned long mark = high_wmark_pages(zone) + balance_gap; - if (IS_ENABLED(CONFIG_COMPACTION) && order && compaction_suitable(zone, - order, 0, classzone_idx) == COMPACT_SKIPPED) - return false; + /* + * When checking from pgdat_balanced(), kswapd should stop and sleep + * when it reaches the high order-0 watermark and let kcompactd take + * over. Other callers such as wakeup_kswapd() want to determine the + * true high-order watermark. + */ + if (IS_ENABLED(CONFIG_COMPACTION) && !highorder) { + mark += (1UL << order); + order = 0; + } - return true; + return zone_watermark_ok_safe(zone, order, mark, classzone_idx); } /* @@ -3029,7 +3034,7 @@ static bool pgdat_balanced(pg_data_t *pgdat, int order, int classzone_idx) continue; } - if (zone_balanced(zone, order, 0, i)) + if (zone_balanced(zone, order, false, 0, i)) balanced_pages += zone->managed_pages; else if (!order) return false; @@ -3083,10 +3088,8 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining, */ static bool kswapd_shrink_zone(struct zone *zone, int classzone_idx, - struct scan_control *sc, - unsigned long *nr_attempted) + struct scan_control *sc) { - int testorder = sc->order; unsigned long balance_gap; bool lowmem_pressure; @@ -3094,17 +3097,6 @@ static bool kswapd_shrink_zone(struct zone *zone, sc->nr_to_reclaim = max(SWAP_CLUSTER_MAX, high_wmark_pages(zone)); /* - * Kswapd reclaims only single pages with compaction enabled. Trying - * too hard to reclaim until contiguous free pages have become - * available can hurt performance by evicting too much useful data - * from memory. Do not reclaim more than needed for compaction. - */ - if (IS_ENABLED(CONFIG_COMPACTION) && sc->order && - compaction_suitable(zone, sc->order, 0, classzone_idx) - != COMPACT_SKIPPED) - testorder = 0; - - /* * We put equal pressure on every zone, unless one zone has way too * many pages free already. The "too many pages" is defined as the * high wmark plus a "gap" where the gap is either the low @@ -3118,15 +3110,12 @@ static bool kswapd_shrink_zone(struct zone *zone, * reclaim is necessary */ lowmem_pressure = (buffer_heads_over_limit && is_highmem(zone)); - if (!lowmem_pressure && zone_balanced(zone, testorder, + if (!lowmem_pressure && zone_balanced(zone, sc->order, false, balance_gap, classzone_idx)) return true; shrink_zone(zone, sc, zone_idx(zone) == classzone_idx); - /* Account for the number of pages attempted to reclaim */ - *nr_attempted += sc->nr_to_reclaim; - clear_bit(ZONE_WRITEBACK, &zone->flags); /* @@ -3136,7 +3125,7 @@ static bool kswapd_shrink_zone(struct zone *zone, * waits. */ if (zone_reclaimable(zone) && - zone_balanced(zone, testorder, 0, classzone_idx)) { + zone_balanced(zone, sc->order, false, 0, classzone_idx)) { clear_bit(ZONE_CONGESTED, &zone->flags); clear_bit(ZONE_DIRTY, &zone->flags); } @@ -3148,7 +3137,7 @@ static bool kswapd_shrink_zone(struct zone *zone, * For kswapd, balance_pgdat() will work across all this node's zones until * they are all at high_wmark_pages(zone). * - * Returns the final order kswapd was reclaiming at + * Returns the highest zone idx kswapd was reclaiming at * * There is special handling here for zones which are full of pinned pages. * This can happen if the pages are all mlocked, or if they are all used by @@ -3165,8 +3154,7 @@ static bool kswapd_shrink_zone(struct zone *zone, * interoperates with the page allocator fallback scheme to ensure that aging * of pages is balanced across the zones. */ -static unsigned long balance_pgdat(pg_data_t *pgdat, int order, - int *classzone_idx) +static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx) { int i; int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ @@ -3183,9 +3171,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, count_vm_event(PAGEOUTRUN); do { - unsigned long nr_attempted = 0; bool raise_priority = true; - bool pgdat_needs_compaction = (order > 0); sc.nr_reclaimed = 0; @@ -3220,7 +3206,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, break; } - if (!zone_balanced(zone, order, 0, 0)) { + if (!zone_balanced(zone, order, false, 0, 0)) { end_zone = i; break; } else { @@ -3236,24 +3222,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, if (i < 0) goto out; - for (i = 0; i <= end_zone; i++) { - struct zone *zone = pgdat->node_zones + i; - - if (!populated_zone(zone)) - continue; - - /* - * If any zone is currently balanced then kswapd will - * not call compaction as it is expected that the - * necessary pages are already available. - */ - if (pgdat_needs_compaction && - zone_watermark_ok(zone, order, - low_wmark_pages(zone), - *classzone_idx, 0)) - pgdat_needs_compaction = false; - } - /* * If we're getting trouble reclaiming, start doing writepage * even in laptop mode. @@ -3297,8 +3265,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, * that that high watermark would be met at 100% * efficiency. */ - if (kswapd_shrink_zone(zone, end_zone, - &sc, &nr_attempted)) + if (kswapd_shrink_zone(zone, end_zone, &sc)) raise_priority = false; } @@ -3311,49 +3278,29 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, pfmemalloc_watermark_ok(pgdat)) wake_up_all(&pgdat->pfmemalloc_wait); - /* - * Fragmentation may mean that the system cannot be rebalanced - * for high-order allocations in all zones. If twice the - * allocation size has been reclaimed and the zones are still - * not balanced then recheck the watermarks at order-0 to - * prevent kswapd reclaiming excessively. Assume that a - * process requested a high-order can direct reclaim/compact. - */ - if (order && sc.nr_reclaimed >= 2UL << order) - order = sc.order = 0; - /* Check if kswapd should be suspending */ if (try_to_freeze() || kthread_should_stop()) break; /* - * Compact if necessary and kswapd is reclaiming at least the - * high watermark number of pages as requsted - */ - if (pgdat_needs_compaction && sc.nr_reclaimed > nr_attempted) - compact_pgdat(pgdat, order); - - /* * Raise priority if scanning rate is too low or there was no * progress in reclaiming pages */ if (raise_priority || !sc.nr_reclaimed) sc.priority--; } while (sc.priority >= 1 && - !pgdat_balanced(pgdat, order, *classzone_idx)); + !pgdat_balanced(pgdat, order, classzone_idx)); out: /* - * Return the order we were reclaiming at so prepare_kswapd_sleep() - * makes a decision on the order we were last reclaiming at. However, - * if another caller entered the allocator slow path while kswapd - * was awake, order will remain at the higher level + * Return the highest zone idx we were reclaiming at so + * prepare_kswapd_sleep() makes the same decisions as here. */ - *classzone_idx = end_zone; - return order; + return end_zone; } -static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) +static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, + int classzone_idx, int balanced_classzone_idx) { long remaining = 0; DEFINE_WAIT(wait); @@ -3364,7 +3311,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); /* Try to sleep for a short interval */ - if (prepare_kswapd_sleep(pgdat, order, remaining, classzone_idx)) { + if (prepare_kswapd_sleep(pgdat, order, remaining, + balanced_classzone_idx)) { remaining = schedule_timeout(HZ/10); finish_wait(&pgdat->kswapd_wait, &wait); prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); @@ -3374,7 +3322,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) * After a short sleep, check if it was a premature sleep. If not, then * go fully to sleep until explicitly woken up. */ - if (prepare_kswapd_sleep(pgdat, order, remaining, classzone_idx)) { + if (prepare_kswapd_sleep(pgdat, order, remaining, + balanced_classzone_idx)) { trace_mm_vmscan_kswapd_sleep(pgdat->node_id); /* @@ -3395,6 +3344,12 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) */ reset_isolation_suitable(pgdat); + /* + * We have freed the memory, now we should compact it to make + * allocation of the requested order possible. + */ + wakeup_kcompactd(pgdat, order, classzone_idx); + if (!kthread_should_stop()) schedule(); @@ -3424,7 +3379,6 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) static int kswapd(void *p) { unsigned long order, new_order; - unsigned balanced_order; int classzone_idx, new_classzone_idx; int balanced_classzone_idx; pg_data_t *pgdat = (pg_data_t*)p; @@ -3457,23 +3411,19 @@ static int kswapd(void *p) set_freezable(); order = new_order = 0; - balanced_order = 0; classzone_idx = new_classzone_idx = pgdat->nr_zones - 1; balanced_classzone_idx = classzone_idx; for ( ; ; ) { bool ret; /* - * If the last balance_pgdat was unsuccessful it's unlikely a - * new request of a similar or harder type will succeed soon - * so consider going to sleep on the basis we reclaimed at + * While we were reclaiming, there might have been another + * wakeup, so check the values. */ - if (balanced_order == new_order) { - new_order = pgdat->kswapd_max_order; - new_classzone_idx = pgdat->classzone_idx; - pgdat->kswapd_max_order = 0; - pgdat->classzone_idx = pgdat->nr_zones - 1; - } + new_order = pgdat->kswapd_max_order; + new_classzone_idx = pgdat->classzone_idx; + pgdat->kswapd_max_order = 0; + pgdat->classzone_idx = pgdat->nr_zones - 1; if (order < new_order || classzone_idx > new_classzone_idx) { /* @@ -3483,7 +3433,7 @@ static int kswapd(void *p) order = new_order; classzone_idx = new_classzone_idx; } else { - kswapd_try_to_sleep(pgdat, balanced_order, + kswapd_try_to_sleep(pgdat, order, classzone_idx, balanced_classzone_idx); order = pgdat->kswapd_max_order; classzone_idx = pgdat->classzone_idx; @@ -3503,9 +3453,8 @@ static int kswapd(void *p) */ if (!ret) { trace_mm_vmscan_kswapd_wake(pgdat->node_id, order); - balanced_classzone_idx = classzone_idx; - balanced_order = balance_pgdat(pgdat, order, - &balanced_classzone_idx); + balanced_classzone_idx = balance_pgdat(pgdat, order, + classzone_idx); } } @@ -3535,7 +3484,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) } if (!waitqueue_active(&pgdat->kswapd_wait)) return; - if (zone_balanced(zone, order, 0, 0)) + if (zone_balanced(zone, order, true, 0, 0)) return; trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); |