NR_WMARK
};
-#define min_wmark_pages(z) (z->_watermark[WMARK_MIN])
-#define low_wmark_pages(z) (z->_watermark[WMARK_LOW])
-#define high_wmark_pages(z) (z->_watermark[WMARK_HIGH])
-#define wmark_pages(z, i) (z->_watermark[i])
+#define min_wmark_pages(z) (z->_watermark[WMARK_MIN] + z->watermark_boost)
+#define low_wmark_pages(z) (z->_watermark[WMARK_LOW] + z->watermark_boost)
+#define high_wmark_pages(z) (z->_watermark[WMARK_HIGH] + z->watermark_boost)
+#define wmark_pages(z, i) (z->_watermark[i] + z->watermark_boost)
struct per_cpu_pages {
int count; /* number of pages in the list */
/* zone watermarks, access with *_wmark_pages(zone) macros */
unsigned long _watermark[NR_WMARK];
+ unsigned long watermark_boost;
unsigned long nr_reserved_highatomic;
struct ctl_table;
int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
+int watermark_boost_factor_sysctl_handler(struct ctl_table *, int,
+ void __user *, size_t *, loff_t *);
int watermark_scale_factor_sysctl_handler(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES];
int min_free_kbytes = 1024;
int user_min_free_kbytes = -1;
+int watermark_boost_factor __read_mostly = 15000;
int watermark_scale_factor = 10;
static unsigned long nr_kernel_pages __meminitdata;
return false;
}
+static inline void boost_watermark(struct zone *zone)
+{
+ unsigned long max_boost;
+
+ if (!watermark_boost_factor)
+ return;
+
+ max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
+ watermark_boost_factor, 10000);
+ max_boost = max(pageblock_nr_pages, max_boost);
+
+ zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
+ max_boost);
+}
+
/*
* This function implements actual steal behaviour. If order is large enough,
* we can steal whole pageblock. If not, we first move freepages in this
* itself, so pages freed in the future will be put on the correct free list.
*/
static void steal_suitable_fallback(struct zone *zone, struct page *page,
- int start_type, bool whole_block)
+ unsigned int alloc_flags, int start_type, bool whole_block)
{
unsigned int current_order = page_order(page);
struct free_area *area;
goto single_page;
}
+ /*
+ * Boost watermarks to increase reclaim pressure to reduce the
+ * likelihood of future fallbacks. Wake kswapd now as the node
+ * may be balanced overall and kswapd will not wake naturally.
+ */
+ boost_watermark(zone);
+ if (alloc_flags & ALLOC_KSWAPD)
+ wakeup_kswapd(zone, 0, 0, zone_idx(zone));
+
/* We are not allowed to try stealing from the whole block */
if (!whole_block)
goto single_page;
page = list_first_entry(&area->free_list[fallback_mt],
struct page, lru);
- steal_suitable_fallback(zone, page, start_migratetype, can_steal);
+ steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
+ can_steal);
trace_mm_page_alloc_extfrag(page, order, current_order,
start_migratetype, fallback_mt);
zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp;
zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
+ zone->watermark_boost = 0;
spin_unlock_irqrestore(&zone->lock, flags);
}
return 0;
}
+int watermark_boost_factor_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ int rc;
+
+ rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
/* Can pages be swapped as part of reclaim? */
unsigned int may_swap:1;
+ /* e.g. boosted watermark reclaim leaves slabs alone */
+ unsigned int may_shrinkslab:1;
+
/*
* Cgroups are not reclaimed below their configured memory.low,
* unless we threaten to OOM. If any cgroups are skipped due to
shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
node_lru_pages += lru_pages;
- shrink_slab(sc->gfp_mask, pgdat->node_id,
+ if (sc->may_shrinkslab) {
+ shrink_slab(sc->gfp_mask, pgdat->node_id,
memcg, sc->priority);
+ }
/* Record the group's reclaim efficiency */
vmpressure(sc->gfp_mask, memcg, false,
.may_writepage = !laptop_mode,
.may_unmap = 1,
.may_swap = 1,
+ .may_shrinkslab = 1,
};
/*
.may_unmap = 1,
.reclaim_idx = MAX_NR_ZONES - 1,
.may_swap = !noswap,
+ .may_shrinkslab = 1,
};
unsigned long lru_pages;
.may_writepage = !laptop_mode,
.may_unmap = 1,
.may_swap = may_swap,
+ .may_shrinkslab = 1,
};
/*
} while (memcg);
}
+static bool pgdat_watermark_boosted(pg_data_t *pgdat, int classzone_idx)
+{
+ int i;
+ struct zone *zone;
+
+ /*
+ * Check for watermark boosts top-down as the higher zones
+ * are more likely to be boosted. Both watermarks and boosts
+ * should not be checked at the time time as reclaim would
+ * start prematurely when there is no boosting and a lower
+ * zone is balanced.
+ */
+ for (i = classzone_idx; i >= 0; i--) {
+ zone = pgdat->node_zones + i;
+ if (!managed_zone(zone))
+ continue;
+
+ if (zone->watermark_boost)
+ return true;
+ }
+
+ return false;
+}
+
/*
* Returns true if there is an eligible zone balanced for the request order
* and classzone_idx
unsigned long mark = -1;
struct zone *zone;
+ /*
+ * Check watermarks bottom-up as lower zones are more likely to
+ * meet watermarks.
+ */
for (i = 0; i <= classzone_idx; i++) {
zone = pgdat->node_zones + i;
unsigned long nr_soft_reclaimed;
unsigned long nr_soft_scanned;
unsigned long pflags;
+ unsigned long nr_boost_reclaim;
+ unsigned long zone_boosts[MAX_NR_ZONES] = { 0, };
+ bool boosted;
struct zone *zone;
struct scan_control sc = {
.gfp_mask = GFP_KERNEL,
.order = order,
- .priority = DEF_PRIORITY,
- .may_writepage = !laptop_mode,
.may_unmap = 1,
- .may_swap = 1,
};
psi_memstall_enter(&pflags);
count_vm_event(PAGEOUTRUN);
+ /*
+ * Account for the reclaim boost. Note that the zone boost is left in
+ * place so that parallel allocations that are near the watermark will
+ * stall or direct reclaim until kswapd is finished.
+ */
+ nr_boost_reclaim = 0;
+ for (i = 0; i <= classzone_idx; i++) {
+ zone = pgdat->node_zones + i;
+ if (!managed_zone(zone))
+ continue;
+
+ nr_boost_reclaim += zone->watermark_boost;
+ zone_boosts[i] = zone->watermark_boost;
+ }
+ boosted = nr_boost_reclaim;
+
+restart:
+ sc.priority = DEF_PRIORITY;
do {
unsigned long nr_reclaimed = sc.nr_reclaimed;
bool raise_priority = true;
+ bool balanced;
bool ret;
sc.reclaim_idx = classzone_idx;
}
/*
- * Only reclaim if there are no eligible zones. Note that
- * sc.reclaim_idx is not used as buffer_heads_over_limit may
- * have adjusted it.
+ * If the pgdat is imbalanced then ignore boosting and preserve
+ * the watermarks for a later time and restart. Note that the
+ * zone watermarks will be still reset at the end of balancing
+ * on the grounds that the normal reclaim should be enough to
+ * re-evaluate if boosting is required when kswapd next wakes.
+ */
+ balanced = pgdat_balanced(pgdat, sc.order, classzone_idx);
+ if (!balanced && nr_boost_reclaim) {
+ nr_boost_reclaim = 0;
+ goto restart;
+ }
+
+ /*
+ * If boosting is not active then only reclaim if there are no
+ * eligible zones. Note that sc.reclaim_idx is not used as
+ * buffer_heads_over_limit may have adjusted it.
*/
- if (pgdat_balanced(pgdat, sc.order, classzone_idx))
+ if (!nr_boost_reclaim && balanced)
goto out;
+ /* Limit the priority of boosting to avoid reclaim writeback */
+ if (nr_boost_reclaim && sc.priority == DEF_PRIORITY - 2)
+ raise_priority = false;
+
+ /*
+ * Do not writeback or swap pages for boosted reclaim. The
+ * intent is to relieve pressure not issue sub-optimal IO
+ * from reclaim context. If no pages are reclaimed, the
+ * reclaim will be aborted.
+ */
+ sc.may_writepage = !laptop_mode && !nr_boost_reclaim;
+ sc.may_swap = !nr_boost_reclaim;
+ sc.may_shrinkslab = !nr_boost_reclaim;
+
/*
* Do some background aging of the anon list, to give
* pages a chance to be referenced before reclaiming. All
* progress in reclaiming pages
*/
nr_reclaimed = sc.nr_reclaimed - nr_reclaimed;
+ nr_boost_reclaim -= min(nr_boost_reclaim, nr_reclaimed);
+
+ /*
+ * If reclaim made no progress for a boost, stop reclaim as
+ * IO cannot be queued and it could be an infinite loop in
+ * extreme circumstances.
+ */
+ if (nr_boost_reclaim && !nr_reclaimed)
+ break;
+
if (raise_priority || !nr_reclaimed)
sc.priority--;
} while (sc.priority >= 1);
pgdat->kswapd_failures++;
out:
+ /* If reclaim was boosted, account for the reclaim done in this pass */
+ if (boosted) {
+ unsigned long flags;
+
+ for (i = 0; i <= classzone_idx; i++) {
+ if (!zone_boosts[i])
+ continue;
+
+ /* Increments are under the zone lock */
+ zone = pgdat->node_zones + i;
+ spin_lock_irqsave(&zone->lock, flags);
+ zone->watermark_boost -= min(zone->watermark_boost, zone_boosts[i]);
+ spin_unlock_irqrestore(&zone->lock, flags);
+ }
+
+ /*
+ * As there is now likely space, wakeup kcompact to defragment
+ * pageblocks.
+ */
+ wakeup_kcompactd(pgdat, pageblock_order, classzone_idx);
+ }
+
snapshot_refaults(NULL, pgdat);
__fs_reclaim_release();
psi_memstall_leave(&pflags);
/* Hopeless node, leave it to direct reclaim if possible */
if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ||
- pgdat_balanced(pgdat, order, classzone_idx)) {
+ (pgdat_balanced(pgdat, order, classzone_idx) &&
+ !pgdat_watermark_boosted(pgdat, classzone_idx))) {
/*
* There may be plenty of free memory available, but it's too
* fragmented for high-order allocations. Wake up kcompactd
projects / openwrt / staging / blogic.git / commitdiff