mm: send one IPI per CPU to TLB flush all entries after unmapping pages

[cascardo/linux.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8286938..99ec00d 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1057,7 +1057,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                 * processes. Try to unmap it here.
                 */
                if (page_mapped(page) && mapping) {
-                       switch (try_to_unmap(page, ttu_flags)) {
+                       switch (try_to_unmap(page,
+                                       ttu_flags|TTU_BATCH_FLUSH)) {
                        case SWAP_FAIL:
                                goto activate_locked;
                        case SWAP_AGAIN:
@@ -1208,6 +1209,7 @@ keep:
        }
 
        mem_cgroup_uncharge_list(&free_pages);
+       try_to_unmap_flush();
        free_hot_cold_page_list(&free_pages, true);
 
        list_splice(&ret_pages, page_list);
@@ -2151,6 +2153,23 @@ out:
        }
 }
 
+#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
+static void init_tlb_ubc(void)
+{
+       /*
+        * This deliberately does not clear the cpumask as it's expensive
+        * and unnecessary. If there happens to be data in there then the
+        * first SWAP_CLUSTER_MAX pages will send an unnecessary IPI and
+        * then will be cleared.
+        */
+       current->tlb_ubc.flush_required = false;
+}
+#else
+static inline void init_tlb_ubc(void)
+{
+}
+#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
+
 /*
  * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
  */
@@ -2185,6 +2204,8 @@ static void shrink_lruvec(struct lruvec *lruvec, int swappiness,
        scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() &&
                         sc->priority == DEF_PRIORITY);
 
+       init_tlb_ubc();
+
        blk_start_plug(&plug);
        while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
                                        nr[LRU_INACTIVE_FILE]) {