macvtap: do not zerocopy if iov needs more pages than MAX_SKB_FRAGS

[~andy/linux] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index bf4778479e3a498b02da17379c59b1639a59ad6b..2cff0d491c6dca84391edd100e1726696c1475d5 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -546,7 +546,6 @@ int remove_mapping(struct address_space *mapping, struct page *page)
 void putback_lru_page(struct page *page)
 {
        int lru;
-       int active = !!TestClearPageActive(page);
        int was_unevictable = PageUnevictable(page);
 
        VM_BUG_ON(PageLRU(page));
@@ -561,8 +560,8 @@ redo:
                 * unevictable page on [in]active list.
                 * We know how to handle that.
                 */
-               lru = active + page_lru_base_type(page);
-               lru_cache_add_lru(page, lru);
+               lru = page_lru_base_type(page);
+               lru_cache_add(page);
        } else {
                /*
                 * Put unevictable pages directly on zone's unevictable
@@ -673,6 +672,8 @@ static enum page_references page_check_references(struct page *page,
 static void page_check_dirty_writeback(struct page *page,
                                       bool *dirty, bool *writeback)
 {
+       struct address_space *mapping;
+
        /*
         * Anonymous pages are not handled by flushers and must be written
         * from reclaim context. Do not stall reclaim based on them
@@ -686,6 +687,14 @@ static void page_check_dirty_writeback(struct page *page,
        /* By default assume that the page flags are accurate */
        *dirty = PageDirty(page);
        *writeback = PageWriteback(page);
+
+       /* Verify dirty/writeback state if the filesystem supports it */
+       if (!page_has_private(page))
+               return;
+
+       mapping = page_mapping(page);
+       if (mapping && mapping->a_ops->is_dirty_writeback)
+               mapping->a_ops->is_dirty_writeback(page, dirty, writeback);
 }
 
 /*
@@ -1434,25 +1443,11 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
         * as there is no guarantee the dirtying process is throttled in the
         * same way balance_dirty_pages() manages.
         *
-        * This scales the number of dirty pages that must be under writeback
-        * before a zone gets flagged ZONE_WRITEBACK. It is a simple backoff
-        * function that has the most effect in the range DEF_PRIORITY to
-        * DEF_PRIORITY-2 which is the priority reclaim is considered to be
-        * in trouble and reclaim is considered to be in trouble.
-        *
-        * DEF_PRIORITY   100% isolated pages must be PageWriteback to throttle
-        * DEF_PRIORITY-1  50% must be PageWriteback
-        * DEF_PRIORITY-2  25% must be PageWriteback, kswapd in trouble
-        * ...
-        * DEF_PRIORITY-6 For SWAP_CLUSTER_MAX isolated pages, throttle if any
-        *                     isolated page is PageWriteback
-        *
         * Once a zone is flagged ZONE_WRITEBACK, kswapd will count the number
         * of pages under pages flagged for immediate reclaim and stall if any
         * are encountered in the nr_immediate check below.
         */
-       if (nr_writeback && nr_writeback >=
-                       (nr_taken >> (DEF_PRIORITY - sc->priority)))
+       if (nr_writeback && nr_writeback == nr_taken)
                zone_set_flag(zone, ZONE_WRITEBACK);
 
        /*
@@ -2352,8 +2347,10 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
                aborted_reclaim = shrink_zones(zonelist, sc);
 
                /*
-                * Don't shrink slabs when reclaiming memory from
-                * over limit cgroups
+                * Don't shrink slabs when reclaiming memory from over limit
+                * cgroups but do shrink slab at least once when aborting
+                * reclaim for compaction to avoid unevenly scanning file/anon
+                * LRU pages over slab pages.
                 */
                if (global_reclaim(sc)) {
                        unsigned long lru_pages = 0;
@@ -2395,7 +2392,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
                                                WB_REASON_TRY_TO_FREE_PAGES);
                        sc->may_writepage = 1;
                }
-       } while (--sc->priority >= 0);
+       } while (--sc->priority >= 0 && !aborted_reclaim);
 
 out:
        delayacct_freepages_end();