unsigned long freed = 0;
unsigned long long delta;
long total_scan;
- long max_pass;
+ long freeable;
long nr;
long new_nr;
int nid = shrinkctl->nid;
long batch_size = shrinker->batch ? shrinker->batch
: SHRINK_BATCH;
- max_pass = shrinker->count_objects(shrinker, shrinkctl);
- if (max_pass == 0)
+ freeable = shrinker->count_objects(shrinker, shrinkctl);
+ if (freeable == 0)
return 0;
/*
total_scan = nr;
delta = (4 * nr_pages_scanned) / shrinker->seeks;
- delta *= max_pass;
+ delta *= freeable;
do_div(delta, lru_pages + 1);
total_scan += delta;
if (total_scan < 0) {
printk(KERN_ERR
"shrink_slab: %pF negative objects to delete nr=%ld\n",
shrinker->scan_objects, total_scan);
- total_scan = max_pass;
+ total_scan = freeable;
}
/*
* shrinkers to return -1 all the time. This results in a large
* nr being built up so when a shrink that can do some work
* comes along it empties the entire cache due to nr >>>
- * max_pass. This is bad for sustaining a working set in
+ * freeable. This is bad for sustaining a working set in
* memory.
*
* Hence only allow the shrinker to scan the entire cache when
* a large delta change is calculated directly.
*/
- if (delta < max_pass / 4)
- total_scan = min(total_scan, max_pass / 2);
+ if (delta < freeable / 4)
+ total_scan = min(total_scan, freeable / 2);
/*
* Avoid risking looping forever due to too large nr value:
* never try to free more than twice the estimate number of
* freeable entries.
*/
- if (total_scan > max_pass * 2)
- total_scan = max_pass * 2;
+ if (total_scan > freeable * 2)
+ total_scan = freeable * 2;
trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
nr_pages_scanned, lru_pages,
- max_pass, delta, total_scan);
+ freeable, delta, total_scan);
/*
* Normally, we should not scan less than batch_size objects in one
*
* We detect the "tight on memory" situations by looking at the total
* number of objects we want to scan (total_scan). If it is greater
- * than the total number of objects on slab (max_pass), we must be
+ * than the total number of objects on slab (freeable), we must be
* scanning at high prio and therefore should try to reclaim as much as
* possible.
*/
while (total_scan >= batch_size ||
- total_scan >= max_pass) {
+ total_scan >= freeable) {
unsigned long ret;
unsigned long nr_to_scan = min(batch_size, total_scan);
TTU_UNMAP|TTU_IGNORE_ACCESS,
&dummy1, &dummy2, &dummy3, &dummy4, &dummy5, true);
list_splice(&clean_pages, page_list);
- __mod_zone_page_state(zone, NR_ISOLATED_FILE, -ret);
+ mod_zone_page_state(zone, NR_ISOLATED_FILE, -ret);
return ret;
}
* If dirty pages are scanned that are not queued for IO, it
* implies that flushers are not keeping up. In this case, flag
* the zone ZONE_TAIL_LRU_DIRTY and kswapd will start writing
- * pages from reclaim context. It will forcibly stall in the
- * next check.
+ * pages from reclaim context.
*/
if (nr_unqueued_dirty == nr_taken)
zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY);
/*
- * In addition, if kswapd scans pages marked marked for
- * immediate reclaim and under writeback (nr_immediate), it
- * implies that pages are cycling through the LRU faster than
+ * If kswapd scans pages marked marked for immediate
+ * reclaim and under writeback (nr_immediate), it implies
+ * that pages are cycling through the LRU faster than
* they are written so also forcibly stall.
*/
- if (nr_unqueued_dirty == nr_taken || nr_immediate)
+ if (nr_immediate)
congestion_wait(BLK_RW_ASYNC, HZ/10);
}
}
/*
- * Prevent the reclaimer from falling into the cache trap: as
- * cache pages start out inactive, every cache fault will tip
- * the scan balance towards the file LRU. And as the file LRU
- * shrinks, so does the window for rotation from references.
- * This means we have a runaway feedback loop where a tiny
- * thrashing file LRU becomes infinitely more attractive than
- * anon pages. Try to detect this based on file LRU size.
- */
- if (global_reclaim(sc)) {
- unsigned long free = zone_page_state(zone, NR_FREE_PAGES);
-
- if (unlikely(file + free <= high_wmark_pages(zone))) {
- scan_balance = SCAN_ANON;
- goto out;
- }
- }
-
- /*
* There is enough inactive page cache, do not reclaim
* anything from the anonymous working set right now.
*/
unsigned long nr_reclaimed = 0;
unsigned long nr_to_reclaim = sc->nr_to_reclaim;
struct blk_plug plug;
- bool scan_adjusted = false;
+ bool scan_adjusted;
get_scan_count(lruvec, sc, nr);
/* Record the original scan target for proportional adjustments later */
memcpy(targets, nr, sizeof(nr));
+ /*
+ * Global reclaiming within direct reclaim at DEF_PRIORITY is a normal
+ * event that can occur when there is little memory pressure e.g.
+ * multiple streaming readers/writers. Hence, we do not abort scanning
+ * when the requested number of pages are reclaimed when scanning at
+ * DEF_PRIORITY on the assumption that the fact we are direct
+ * reclaiming implies that kswapd is not keeping up and it is best to
+ * do a batch of work at once. For memcg reclaim one check is made to
+ * abort proportional reclaim if either the file or anon lru has already
+ * dropped to zero at the first pass.
+ */
+ scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() &&
+ sc->priority == DEF_PRIORITY);
+
blk_start_plug(&plug);
while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
nr[LRU_INACTIVE_FILE]) {
continue;
/*
- * For global direct reclaim, reclaim only the number of pages
- * requested. Less care is taken to scan proportionally as it
- * is more important to minimise direct reclaim stall latency
- * than it is to properly age the LRU lists.
- */
- if (global_reclaim(sc) && !current_is_kswapd())
- break;
-
- /*
* For kswapd and memcg, reclaim at least the number of pages
- * requested. Ensure that the anon and file LRUs shrink
+ * requested. Ensure that the anon and file LRUs are scanned
* proportionally what was requested by get_scan_count(). We
* stop reclaiming one LRU and reduce the amount scanning
* proportional to the original scan target.
nr_file = nr[LRU_INACTIVE_FILE] + nr[LRU_ACTIVE_FILE];
nr_anon = nr[LRU_INACTIVE_ANON] + nr[LRU_ACTIVE_ANON];
+ /*
+ * It's just vindictive to attack the larger once the smaller
+ * has gone to zero. And given the way we stop scanning the
+ * smaller below, this makes sure that we only make one nudge
+ * towards proportionality once we've got nr_to_reclaim.
+ */
+ if (!nr_file || !nr_anon)
+ break;
+
if (nr_file > nr_anon) {
unsigned long scan_target = targets[LRU_INACTIVE_ANON] +
targets[LRU_ACTIVE_ANON] + 1;
unsigned long lru_pages = 0;
nodes_clear(shrink->nodes_to_scan);
- for_each_zone_zonelist(zone, z, zonelist,
- gfp_zone(sc->gfp_mask)) {
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ gfp_zone(sc->gfp_mask), sc->nodemask) {
if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
continue;
for (i = 0; i <= ZONE_NORMAL; i++) {
zone = &pgdat->node_zones[i];
+ if (!populated_zone(zone))
+ continue;
+
pfmemalloc_reserve += min_wmark_pages(zone);
free_pages += zone_page_state(zone, NR_FREE_PAGES);
}
+ /* If there are no reserves (unexpected config) then do not throttle */
+ if (!pfmemalloc_reserve)
+ return true;
+
wmark_ok = free_pages > pfmemalloc_reserve / 2;
/* kswapd must be awake if processes are being throttled */
static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist,
nodemask_t *nodemask)
{
+ struct zoneref *z;
struct zone *zone;
- int high_zoneidx = gfp_zone(gfp_mask);
- pg_data_t *pgdat;
+ pg_data_t *pgdat = NULL;
/*
* Kernel threads should not be throttled as they may be indirectly
if (fatal_signal_pending(current))
goto out;
- /* Check if the pfmemalloc reserves are ok */
- first_zones_zonelist(zonelist, high_zoneidx, NULL, &zone);
- pgdat = zone->zone_pgdat;
- if (pfmemalloc_watermark_ok(pgdat))
+ /*
+ * Check if the pfmemalloc reserves are ok by finding the first node
+ * with a usable ZONE_NORMAL or lower zone. The expectation is that
+ * GFP_KERNEL will be required for allocating network buffers when
+ * swapping over the network so ZONE_HIGHMEM is unusable.
+ *
+ * Throttling is based on the first usable node and throttled processes
+ * wait on a queue until kswapd makes progress and wakes them. There
+ * is an affinity then between processes waking up and where reclaim
+ * progress has been made assuming the process wakes on the same node.
+ * More importantly, processes running on remote nodes will not compete
+ * for remote pfmemalloc reserves and processes on different nodes
+ * should make reasonable progress.
+ */
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ gfp_mask, nodemask) {
+ if (zone_idx(zone) > ZONE_NORMAL)
+ continue;
+
+ /* Throttle based on the first usable node */
+ pgdat = zone->zone_pgdat;
+ if (pfmemalloc_watermark_ok(pgdat))
+ goto out;
+ break;
+ }
+
+ /* If no zone was usable by the allocation flags then do not throttle */
+ if (!pgdat)
goto out;
/* Account for the throttling */
}
}
+ tsk->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD);
current->reclaim_state = NULL;
+ lockdep_clear_current_reclaim_state();
+
return 0;
}
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blobdiff