From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756659AbcECVCa (ORCPT ); Tue, 3 May 2016 17:02:30 -0400 Received: from mga11.intel.com ([192.55.52.93]:22567 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756436AbcECVC2 (ORCPT ); Tue, 3 May 2016 17:02:28 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,574,1455004800"; d="scan'208";a="798051518" Message-ID: <1462309346.21143.11.camel@linux.intel.com> Subject: [PATCH 4/7] mm: Shrink page list batch allocates swap slots for page swapping From: Tim Chen To: Andrew Morton , Vladimir Davydov , Johannes Weiner , Michal Hocko , Minchan Kim , Hugh Dickins Cc: "Kirill A.Shutemov" , Andi Kleen , Aaron Lu , Huang Ying , linux-mm , linux-kernel@vger.kernel.org Date: Tue, 03 May 2016 14:02:26 -0700 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In shrink page list, we take advantage bulk allocation of swap entries with the new get_swap_pages function. This reduces contention on a swap device's swap_info lock. When the memory is low and the system is actively trying to reclaim memory, both direct reclaim path and kswapd contends on this lock when they access the same swap partition. Signed-off-by: Tim Chen ---  mm/vmscan.c | 63 ++++++++++++++++++++++++++++++++++++++++---------------------  1 file changed, 42 insertions(+), 21 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index e36d8a7..310e2b2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1096,38 +1096,59 @@ static unsigned long shrink_anon_page_list(struct list_head *page_list,  {   unsigned long nr_reclaimed = 0;   enum pg_result pg_dispose; + swp_entry_t swp_entries[SWAP_BATCH]; + struct page *page; + int m, i, k;     while (n > 0) { - struct page *page;   int swap_ret = SWAP_SUCCESS;   - --n; - if (list_empty(swap_pages)) -        return nr_reclaimed; + m = get_swap_pages(n, swp_entries); + if (!m) + goto no_swap_slots; + n -= m; + for (i = 0; i < m; ++i) { + if (list_empty(swap_pages)) { + /* free any leftover swap slots */ + for (k = i; k < m; ++k) + swapcache_free(swp_entries[k]); + return nr_reclaimed; + } + page = lru_to_page(swap_pages);   - page = lru_to_page(swap_pages); + list_del(&page->lru);   - list_del(&page->lru); + /* + * Anonymous process memory has backing store? + * Try to allocate it some swap space here. + */ + + if (!add_to_swap(page, page_list, NULL)) { + pg_finish(page, PG_ACTIVATE_LOCKED, swap_ret, + &nr_reclaimed, pgactivate, + ret_pages, free_pages); + continue; + }   - /* - * Anonymous process memory has backing store? - * Try to allocate it some swap space here. - */ + if (clean) + pg_dispose = handle_pgout(page_list, zone, sc, + ttu_flags, PAGEREF_RECLAIM_CLEAN, + true, true, &swap_ret, page); + else + pg_dispose = handle_pgout(page_list, zone, sc, + ttu_flags, PAGEREF_RECLAIM, + true, true, &swap_ret, page);   - if (!add_to_swap(page, page_list, NULL)) { - pg_finish(page, PG_ACTIVATE_LOCKED, swap_ret, &nr_reclaimed, + pg_finish(page, pg_dispose, swap_ret, &nr_reclaimed,   pgactivate, ret_pages, free_pages); - continue;   } + } + return nr_reclaimed;   - if (clean) - pg_dispose = handle_pgout(page_list, zone, sc, ttu_flags, - PAGEREF_RECLAIM_CLEAN, true, true, &swap_ret, page); - else - pg_dispose = handle_pgout(page_list, zone, sc, ttu_flags, - PAGEREF_RECLAIM, true, true, &swap_ret, page); - - pg_finish(page, pg_dispose, swap_ret, &nr_reclaimed, +no_swap_slots: + while (!list_empty(swap_pages)) { + page = lru_to_page(swap_pages); + pg_finish(page, PG_ACTIVATE_LOCKED, 0, &nr_reclaimed,   pgactivate, ret_pages, free_pages);   }   return nr_reclaimed; --  2.5.5