From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 3E0146B0292 for ; Mon, 7 Aug 2017 01:41:56 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id r187so85075021pfr.8 for ; Sun, 06 Aug 2017 22:41:56 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id f83si4233583pfk.367.2017.08.06.22.41.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 06 Aug 2017 22:41:55 -0700 (PDT) From: "Huang, Ying" Subject: [PATCH -mm -v4 1/5] mm, swap: Add swap readahead hit statistics Date: Mon, 7 Aug 2017 13:40:34 +0800 Message-Id: <20170807054038.1843-2-ying.huang@intel.com> In-Reply-To: <20170807054038.1843-1-ying.huang@intel.com> References: <20170807054038.1843-1-ying.huang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Johannes Weiner , Minchan Kim , Rik van Riel , Shaohua Li , Hugh Dickins , Fengguang Wu , Tim Chen , Dave Hansen From: Huang Ying The statistics for total readahead pages and total readahead hits are recorded and exported via the following sysfs interface. /sys/kernel/mm/swap/ra_hits /sys/kernel/mm/swap/ra_total With them, the efficiency of the swap readahead could be measured, so that the swap readahead algorithm and parameters could be tuned accordingly. Signed-off-by: "Huang, Ying" Cc: Johannes Weiner Cc: Minchan Kim Cc: Rik van Riel Cc: Shaohua Li Cc: Hugh Dickins Cc: Fengguang Wu Cc: Tim Chen Cc: Dave Hansen --- include/linux/vm_event_item.h | 2 ++ mm/swap_state.c | 9 +++++++-- mm/vmstat.c | 3 +++ 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index e02820fc2861..27e3339cfd65 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -106,6 +106,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, VMACACHE_FIND_HITS, VMACACHE_FULL_FLUSHES, #endif + SWAP_RA, + SWAP_RA_HIT, NR_VM_EVENT_ITEMS }; diff --git a/mm/swap_state.c b/mm/swap_state.c index b68c93014f50..d1bdb31cab13 100644 --- 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); diff --git a/mm/vmstat.c b/mm/vmstat.c index ba9b202e8500..4c2121a8b877 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1095,6 +1095,9 @@ const char * const vmstat_text[] = { "vmacache_find_hits", "vmacache_full_flushes", #endif + + "swap_ra", + "swap_ra_hit", #endif /* CONFIG_VM_EVENTS_COUNTERS */ }; #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */ -- 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org