return nr;
}
-unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat)
-{
- unsigned long nr;
-
- nr = node_page_state_snapshot(pgdat, NR_ACTIVE_FILE) +
- node_page_state_snapshot(pgdat, NR_INACTIVE_FILE) +
- node_page_state_snapshot(pgdat, NR_ISOLATED_FILE);
-
- if (get_nr_swap_pages() > 0)
- nr += node_page_state_snapshot(pgdat, NR_ACTIVE_ANON) +
- node_page_state_snapshot(pgdat, NR_INACTIVE_ANON) +
- node_page_state_snapshot(pgdat, NR_ISOLATED_ANON);
-
- return nr;
-}
-
/**
* lruvec_lru_size - Returns the number of pages on the given LRU list.
* @lruvec: lru vector
#define SHRINK_BATCH 128
static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
- struct shrinker *shrinker,
- unsigned long nr_scanned,
- unsigned long nr_eligible)
+ struct shrinker *shrinker, int priority)
{
unsigned long freed = 0;
unsigned long long delta;
nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
total_scan = nr;
- delta = (4 * nr_scanned) / shrinker->seeks;
- delta *= freeable;
- do_div(delta, nr_eligible + 1);
+ delta = freeable >> priority;
+ delta *= 4;
+ do_div(delta, shrinker->seeks);
total_scan += delta;
if (total_scan < 0) {
pr_err("shrink_slab: %pF negative objects to delete nr=%ld\n",
total_scan = freeable * 2;
trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
- nr_scanned, nr_eligible,
- freeable, delta, total_scan);
+ freeable, delta, total_scan, priority);
/*
* Normally, we should not scan less than batch_size objects in one
* @gfp_mask: allocation context
* @nid: node whose slab caches to target
* @memcg: memory cgroup whose slab caches to target
- * @nr_scanned: pressure numerator
- * @nr_eligible: pressure denominator
+ * @priority: the reclaim priority
*
* Call the shrink functions to age shrinkable caches.
*
* objects from the memory cgroup specified. Otherwise, only unaware
* shrinkers are called.
*
- * @nr_scanned and @nr_eligible form a ratio that indicate how much of
- * the available objects should be scanned. Page reclaim for example
- * passes the number of pages scanned and the number of pages on the
- * LRU lists that it considered on @nid, plus a bias in @nr_scanned
- * when it encountered mapped pages. The ratio is further biased by
- * the ->seeks setting of the shrink function, which indicates the
- * cost to recreate an object relative to that of an LRU page.
+ * @priority is sc->priority, we take the number of objects and >> by priority
+ * in order to get the scan target.
*
* Returns the number of reclaimed slab objects.
*/
static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
struct mem_cgroup *memcg,
- unsigned long nr_scanned,
- unsigned long nr_eligible)
+ int priority)
{
struct shrinker *shrinker;
unsigned long freed = 0;
if (memcg && (!memcg_kmem_enabled() || !mem_cgroup_online(memcg)))
return 0;
- if (nr_scanned == 0)
- nr_scanned = SWAP_CLUSTER_MAX;
-
if (!down_read_trylock(&shrinker_rwsem)) {
/*
* If we would return 0, our callers would understand that we
if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
sc.nid = 0;
- freed += do_shrink_slab(&sc, shrinker, nr_scanned, nr_eligible);
+ freed += do_shrink_slab(&sc, shrinker, priority);
+ /*
+ * Bail out if someone want to register a new shrinker to
+ * prevent the regsitration from being stalled for long periods
+ * by parallel ongoing shrinking.
+ */
+ if (rwsem_is_contended(&shrinker_rwsem)) {
+ freed = freed ? : 1;
+ break;
+ }
}
up_read(&shrinker_rwsem);
freed = 0;
do {
- freed += shrink_slab(GFP_KERNEL, nid, memcg,
- 1000, 1000);
+ freed += shrink_slab(GFP_KERNEL, nid, memcg, 0);
} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
} while (freed > 10);
}
if (PageDirty(page)) {
struct address_space *mapping;
+ bool migrate_dirty;
/*
* Only pages without mappings or that have a
* ->migratepage callback are possible to migrate
- * without blocking
+ * without blocking. However, we can be racing with
+ * truncation so it's necessary to lock the page
+ * to stabilise the mapping as truncation holds
+ * the page lock until after the page is removed
+ * from the page cache.
*/
+ if (!trylock_page(page))
+ return ret;
+
mapping = page_mapping(page);
- if (mapping && !mapping->a_ops->migratepage)
+ migrate_dirty = mapping && mapping->a_ops->migratepage;
+ unlock_page(page);
+ if (!migrate_dirty)
return ret;
}
}
* found will be decremented.
*
* Restrictions:
+ *
* (1) Must be called with an elevated refcount on the page. This is a
* fundamentnal difference from isolate_lru_pages (which is called
* without a stable reference).
reclaimed = sc->nr_reclaimed;
scanned = sc->nr_scanned;
-
shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
node_lru_pages += lru_pages;
if (memcg)
shrink_slab(sc->gfp_mask, pgdat->node_id,
- memcg, sc->nr_scanned - scanned,
- lru_pages);
+ memcg, sc->priority);
/* Record the group's reclaim efficiency */
vmpressure(sc->gfp_mask, memcg, false,
}
} while ((memcg = mem_cgroup_iter(root, memcg, &reclaim)));
- /*
- * Shrink the slab caches in the same proportion that
- * the eligible LRU pages were scanned.
- */
if (global_reclaim(sc))
shrink_slab(sc->gfp_mask, pgdat->node_id, NULL,
- sc->nr_scanned - nr_scanned,
- node_lru_pages);
+ sc->priority);
if (reclaim_state) {
sc->nr_reclaimed += reclaim_state->reclaimed_slab;
git.samba.org / sfrench / cifs-2.6.git / blobdiff