From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F157EC433E0 for ; Mon, 8 Mar 2021 15:42:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A8A76521D for ; Mon, 8 Mar 2021 15:42:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A8A76521D Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EF1128D0033; Mon, 8 Mar 2021 10:42:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E7C3C8D001D; Mon, 8 Mar 2021 10:42:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D41CF8D0033; Mon, 8 Mar 2021 10:42:48 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0093.hostedemail.com [216.40.44.93]) by kanga.kvack.org (Postfix) with ESMTP id B50B78D001D for ; Mon, 8 Mar 2021 10:42:48 -0500 (EST) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 60B61362D for ; Mon, 8 Mar 2021 15:42:48 +0000 (UTC) X-FDA: 77897124816.10.093A0FB Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf27.hostedemail.com (Postfix) with ESMTP id BD7138019162 for ; Mon, 8 Mar 2021 15:42:44 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1615218165; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PSwAr01wd8o8Gcv7XoZ8VHOldRlri/BnhPEeNOyHtBc=; b=kOCeT9ZjJ57p59c0D18mLh85tj1k/zY1lAzk/tqohe4PTVOW9pCHNrOAzxSZ66Fx+c1rbU 9n12STBBoSSmTvK7t7UK7pN7SsPXjPeX+eiF9R36bUFqIlacqTkxBp9nrAR3+G39hXaf5M Y4UkVEToPD7Vn2xo+NU1rOrYKrLzmUM= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A20A8AE05; Mon, 8 Mar 2021 15:42:45 +0000 (UTC) Date: Mon, 8 Mar 2021 16:42:43 +0100 From: Michal Hocko To: David Hildenbrand Cc: Minchan Kim , Andrew Morton , linux-mm , LKML , joaodias@google.com Subject: Re: [PATCH] mm: be more verbose for alloc_contig_range faliures Message-ID: References: <9f7b4b8a-5317-e382-7f21-01667e017982@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9f7b4b8a-5317-e382-7f21-01667e017982@redhat.com> X-Stat-Signature: ymcpn81irt8ne3z5qiwpcx3uob5wwp3f X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: BD7138019162 Received-SPF: none (suse.com>: No applicable sender policy available) receiver=imf27; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615218164-291282 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon 08-03-21 15:13:35, David Hildenbrand wrote: > On 08.03.21 15:11, Michal Hocko wrote: > > On Mon 08-03-21 14:22:12, David Hildenbrand wrote: > > > On 08.03.21 13:49, Michal Hocko wrote: > > [...] > > > > Earlier in the discussion I have suggested dynamic debugging facility. > > > > Documentation/admin-guide/dynamic-debug-howto.rst. Have you tried to > > > > look into that direction? > > > > > > Did you see the previous mail this is based on: > > > > > > https://lkml.kernel.org/r/YEEUq8ZRn4WyYWVx@google.com > > > > > > I agree that "nofail" is misleading. Rather something like > > > "dump_on_failure", just a better name :) > > > > Yeah, I have read through the email thread. I just do not get why we > > cannot make it pr_debug() and add -DDYNAMIC_DEBUG_MODULE for > > page_alloc.c (I haven't checked whether that is possible for built in > > compile units, maybe it is not but from a quick seems it should). > > > > I really do not like this to be a part of the API. alloc_contig_range is > > Which API? Any level of the alloc_contig_range api because I strongly suspect that once there is something on the lower levels there will be a push to have it in the directly consumed api as well. Besides that I think this is just a wrong way to approach the problem. > It does not affect alloc_contig_range() itself, it's used > internally only. Sure, we could simply pr_debug() for each and every > migration failure. As long as it's default-disabled, sure. > > I do agree that we should look into properly including this into the dynamic > debugging ifrastructure. Yeah, unless we learn this is not feasible for some reason, which I do not see right now, then let's just make it pr_debug with the runtime control. -- Michal Hocko SUSE Labs