* stalls if we need to run get_block(). We could test
* PagePrivate for that.
*
- * If this process is currently in __generic_file_aio_write() against
+ * If this process is currently in __generic_file_write_iter() against
* this page's queue, we can perform writeback even if that
* will block.
*
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;
}
file = get_lru_size(lruvec, LRU_ACTIVE_FILE) +
get_lru_size(lruvec, LRU_INACTIVE_FILE);
+ /*
+ * 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.