mm, swap: add swap readahead hit statistics

[sfrench/cifs-2.6.git] / mm / swap_state.c

diff --git a/mm/swap_state.c b/mm/swap_state.c
index b68c93014f50c681b5bc1f3d9da2cd8db1fe025a..d1bdb31cab13179bd9b3ff6e2d9f67d927239b95 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -305,8 +305,10 @@ struct page * lookup_swap_cache(swp_entry_t entry)
 
        if (page && likely(!PageTransCompound(page))) {
                INC_CACHE_INFO(find_success);
-               if (TestClearPageReadahead(page))
+               if (TestClearPageReadahead(page)) {
                        atomic_inc(&swapin_readahead_hits);
+                       count_vm_event(SWAP_RA_HIT);
+               }
        }
 
        INC_CACHE_INFO(find_total);
@@ -516,8 +518,11 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
                                                gfp_mask, vma, addr, false);
                if (!page)
                        continue;
-               if (offset != entry_offset && likely(!PageTransCompound(page)))
+               if (offset != entry_offset &&
+                   likely(!PageTransCompound(page))) {
                        SetPageReadahead(page);
+                       count_vm_event(SWAP_RA);
+               }
                put_page(page);
        }
        blk_finish_plug(&plug);