Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yu Zhao , Michal Hocko , Vladimir Davydov , Andrew Morton , Linus Torvalds Subject: [PATCH 3.18 29/32] swap: cond_resched in swap_cgroup_prepare() Date: Mon, 19 Jun 2017 23:21:13 +0800 Message-Id: <20170619152037.284858108@linuxfoundation.org> In-Reply-To: <20170619152035.750974520@linuxfoundation.org> References: <20170619152035.750974520@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Zhao commit ef70762948dde012146926720b70e79736336764 upstream. I saw need_resched() warnings when swapping on large swapfile (TBs) because continuously allocating many pages in swap_cgroup_prepare() took too long. We already cond_resched when freeing page in swap_cgroup_swapoff(). Do the same for the page allocation. Link: http://lkml.kernel.org/r/20170604200109.17606-1-yuzhao@google.com Signed-off-by: Yu Zhao Acked-by: Michal Hocko Acked-by: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_cgroup.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -368,6 +368,9 @@ static int swap_cgroup_prepare(int type) if (!page) goto not_enough_page; ctrl->map[idx] = page; + + if (!(idx % SWAP_CLUSTER_MAX)) + cond_resched(); } return 0; not_enough_page: