From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f197.google.com (mail-ob0-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 5FD116B0005 for ; Tue, 24 May 2016 22:11:24 -0400 (EDT) Received: by mail-ob0-f197.google.com with SMTP id g6so54800070obn.0 for ; Tue, 24 May 2016 19:11:24 -0700 (PDT) Received: from mail-io0-x22a.google.com (mail-io0-x22a.google.com. [2607:f8b0:4001:c06::22a]) by mx.google.com with ESMTPS id 4si20236731itz.98.2016.05.24.19.11.23 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 May 2016 19:11:23 -0700 (PDT) Received: by mail-io0-x22a.google.com with SMTP id t40so23898629ioi.0 for ; Tue, 24 May 2016 19:11:23 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20160523144711.GV2278@dhcp22.suse.cz> <20160523190051.GF32715@dhcp22.suse.cz> <20160524115049.GH8259@dhcp22.suse.cz> Date: Wed, 25 May 2016 10:11:23 +0800 Message-ID: Subject: Re: page order 0 allocation fail but free pages are enough From: yoma sophian Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org >> free-free_cma = 636kB so you are way below the watermark and that is > After tracing the __alloc_pages_slowpath, in the 2nd time we call > get_page_from_freelist, we will purposely put alloc_flags & > ~ALLOC_NO_WATERMARKS. > Doesn't that mean kernel will bypass __zone_watermark_ok? I apologize for my misunderstanding. (alloc_flags & ~ALLOC_NO_WATERMARKS) will NOT bypass __zone_watermark_ok. on the contrary, it will filter out watermarks checking. there is one thing makes me curious, why we put alloc_flags = gfp_to_alloc_flags(gfp_mask) in __alloc_pages_slowpath instead of __alloc_pages_nodemask? Appreciate your kind help, -- 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