From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 81CA36B027E for ; Thu, 19 Jul 2018 04:49:11 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id u16-v6so3734871pfm.15 for ; Thu, 19 Jul 2018 01:49:11 -0700 (PDT) Received: from mga07.intel.com (mga07.intel.com. [134.134.136.100]) by mx.google.com with ESMTPS id x18-v6si4948122pll.193.2018.07.19.01.49.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Jul 2018 01:49:10 -0700 (PDT) From: Huang Ying Subject: [PATCH v3 8/8] swap, put_swap_page: Share more between huge/normal code path Date: Thu, 19 Jul 2018 16:48:42 +0800 Message-Id: <20180719084842.11385-9-ying.huang@intel.com> In-Reply-To: <20180719084842.11385-1-ying.huang@intel.com> References: <20180719084842.11385-1-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 , Dave Hansen , Michal Hocko , Johannes Weiner , Shaohua Li , Hugh Dickins , Minchan Kim , Rik van Riel , Dan Williams , Daniel Jordan In this patch, locking related code is shared between huge/normal code path in put_swap_page() to reduce code duplication. And `free_entries == 0` case is merged into more general `free_entries != SWAPFILE_CLUSTER` case, because the new locking method makes it easy. The added lines is same as the removed lines. But the code size is increased when CONFIG_TRANSPARENT_HUGEPAGE=n. text data bss dec hex filename base: 24123 2004 340 26467 6763 mm/swapfile.o unified: 24485 2004 340 26829 68cd mm/swapfile.o Dig on step deeper with `size -A mm/swapfile.o` for base and unified kernel and compare the result, yields, -.text 17723 0 +.text 17835 0 -.orc_unwind_ip 1380 0 +.orc_unwind_ip 1480 0 -.orc_unwind 2070 0 +.orc_unwind 2220 0 -Total 26686 +Total 27048 The total difference is the same. The text segment difference is much smaller: 112. More difference comes from the ORC unwinder segments: (1480 + 2220) - (1380 + 2070) = 250. If the frame pointer unwinder is used, this costs nothing. Signed-off-by: "Huang, Ying" Reviewed-by: Daniel Jordan Cc: Dave Hansen Cc: Michal Hocko Cc: Johannes Weiner Cc: Shaohua Li Cc: Hugh Dickins Cc: Minchan Kim Cc: Rik van Riel Cc: Dan Williams --- mm/swapfile.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index d313f7512d26..2fe2e93cee0e 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1284,8 +1284,8 @@ void put_swap_page(struct page *page, swp_entry_t entry) if (!si) return; + ci = lock_cluster_or_swap_info(si, offset); if (size == SWAPFILE_CLUSTER) { - ci = lock_cluster(si, offset); VM_BUG_ON(!cluster_is_huge(ci)); map = si->swap_map + offset; for (i = 0; i < SWAPFILE_CLUSTER; i++) { @@ -1294,13 +1294,9 @@ void put_swap_page(struct page *page, swp_entry_t entry) if (val == SWAP_HAS_CACHE) free_entries++; } - if (!free_entries) { - for (i = 0; i < SWAPFILE_CLUSTER; i++) - map[i] &= ~SWAP_HAS_CACHE; - } cluster_clear_huge(ci); - unlock_cluster(ci); if (free_entries == SWAPFILE_CLUSTER) { + unlock_cluster_or_swap_info(si, ci); spin_lock(&si->lock); ci = lock_cluster(si, offset); memset(map, 0, SWAPFILE_CLUSTER); @@ -1311,12 +1307,16 @@ void put_swap_page(struct page *page, swp_entry_t entry) return; } } - if (size == 1 || free_entries) { - for (i = 0; i < size; i++, entry.val++) { - if (!__swap_entry_free(si, entry, SWAP_HAS_CACHE)) - free_swap_slot(entry); + for (i = 0; i < size; i++, entry.val++) { + if (!__swap_entry_free_locked(si, offset + i, SWAP_HAS_CACHE)) { + unlock_cluster_or_swap_info(si, ci); + free_swap_slot(entry); + if (i == size - 1) + return; + lock_cluster_or_swap_info(si, offset); } } + unlock_cluster_or_swap_info(si, ci); } #ifdef CONFIG_THP_SWAP -- 2.16.4