From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-f72.google.com (mail-lf1-f72.google.com [209.85.167.72]) by kanga.kvack.org (Postfix) with ESMTP id 3B3006B0007 for ; Sun, 4 Nov 2018 17:13:17 -0500 (EST) Received: by mail-lf1-f72.google.com with SMTP id p19so895273lfg.5 for ; Sun, 04 Nov 2018 14:13:17 -0800 (PST) Received: from relay.sw.ru (relay.sw.ru. [185.231.240.75]) by mx.google.com with ESMTPS id q22si30629394lfj.86.2018.11.04.14.13.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 04 Nov 2018 14:13:15 -0800 (PST) From: Vasily Averin Subject: [PATCH 2/2] mm: avoid unnecessary swap_info_struct allocation Message-ID: Date: Mon, 5 Nov 2018 01:13:12 +0300 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, Andrew Morton Cc: Huang Ying , linux-kernel@vger.kernel.org, Aaron Lu Currently newly allocated swap_info_struct can be quickly freed. This patch avoid uneccessary high-order page allocation and helps to decrease the memory pressure. Signed-off-by: Vasily Averin --- mm/swapfile.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 8688ae65ef58..53ec2f0cdf26 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2809,14 +2809,17 @@ late_initcall(max_swapfiles_check); static struct swap_info_struct *alloc_swap_info(void) { - struct swap_info_struct *p; + struct swap_info_struct *p = NULL; unsigned int type; int i; + bool force_alloc = false; - p = kvzalloc(sizeof(*p), GFP_KERNEL); - if (!p) - return ERR_PTR(-ENOMEM); - +retry: + if (force_alloc) { + p = kvzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return ERR_PTR(-ENOMEM); + } spin_lock(&swap_lock); for (type = 0; type < nr_swapfiles; type++) { if (!(swap_info[type]->flags & SWP_USED)) @@ -2828,6 +2831,11 @@ static struct swap_info_struct *alloc_swap_info(void) return ERR_PTR(-EPERM); } if (type >= nr_swapfiles) { + if (!force_alloc) { + force_alloc = true; + spin_unlock(&swap_lock); + goto retry; + } p->type = type; swap_info[type] = p; /* -- 2.17.1