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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 E67E1C433DB for ; Tue, 30 Mar 2021 16:53:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 919C161994 for ; Tue, 30 Mar 2021 16:53:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 919C161994 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 297EC6B0083; Tue, 30 Mar 2021 12:53:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 26F356B0085; Tue, 30 Mar 2021 12:53:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 122296B0087; Tue, 30 Mar 2021 12:53:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0002.hostedemail.com [216.40.44.2]) by kanga.kvack.org (Postfix) with ESMTP id EC7076B0083 for ; Tue, 30 Mar 2021 12:53:23 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id A5118181AC9B6 for ; Tue, 30 Mar 2021 16:53:23 +0000 (UTC) X-FDA: 77977136286.29.FA15958 Received: from mail-ej1-f48.google.com (mail-ej1-f48.google.com [209.85.218.48]) by imf24.hostedemail.com (Postfix) with ESMTP id C195DA000396 for ; Tue, 30 Mar 2021 16:53:10 +0000 (UTC) Received: by mail-ej1-f48.google.com with SMTP id r12so25854712ejr.5 for ; Tue, 30 Mar 2021 09:53:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=YDPKwOgaNtuLy8HADDzZv+0fyVoW5LtAh6tAlz9JJjQ=; b=nynAqfNbY+ydK0ogMiiI0jzRpX/AiFs4naJXjQphpjQx10oPU1+TffpOooeafTP5D4 sEsnBKV/6dwiuUVpwvvJst2dzTCy9UI6/Qyu8YxRDIRSlbc554Rx/Bv9ySa7cx41TGeC FCkP+gKIRz9A+D0RNB07Acf9R8ys+fp/bQ1D7FBwHC7lg6ozrXnQrnDYEw1OslzwqC58 tOYCneB2EPe08mHVrJw2PH10m60SjNwm4kycCwdELq7UMY23i3288fa9auTLLe0cc/W7 Uk51QsGO/dZi5qI/tfyaMswZoeoidMgmEY0SqyUVpCASC5j4uYKAizx7HLU88wHWipqv tBRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=YDPKwOgaNtuLy8HADDzZv+0fyVoW5LtAh6tAlz9JJjQ=; b=tlUH9k2xOrtdXJFN0LoyBarz2HE7r2Fja7v2glZ4gRrr6LrNvDdSJ4hxvfrapilq87 BKYsLVb3pQp0z0HlM9/gHvHFDlQbEXogRROMfZ18RqWmfwLSt3K9b4zmkBAvMVGsgGZ7 N93Bj4PDQi362G0kiEp1Fcx3XoWvO430b1hz4tKIvyjiLtX/oyNdgMHx+FD7jeWFwTM7 wH8/HYyoIlJuGjYYURzBYJ+INxnG1fi1wTvFlxUwyoP3BKPVtiiXtqtG9ZFM2e/M2cGa uZDmjy+UIQTUNQAcSJqnBvJWjtvwi3H9WZdwk0ZSZzyq6k2qR32eOCICfMjgBaicuUZm VcVw== X-Gm-Message-State: AOAM530NKA9oHYG4cQE2ahds26jFA1Ta3uhPN6obSS16t3Gczp6z0yml fGKXdDkXDSwkeDJCQ78+OaJY7Y01QLO1JK8r+CI= X-Google-Smtp-Source: ABdhPJzQkqtXRjQQNfasrAxhS2Owc15KpQZWsJrOKpu8LvK9Sx0DLVUo1W1FyJoFcqPE/GEuSGSdAG+tBq2YywViR10= X-Received: by 2002:a17:906:4bce:: with SMTP id x14mr33384490ejv.383.1617123192815; Tue, 30 Mar 2021 09:53:12 -0700 (PDT) MIME-Version: 1.0 References: <20210329183312.178266-1-shy828301@gmail.com> <20210329183312.178266-6-shy828301@gmail.com> <20210330164207.3a2826f7@thinkpad> In-Reply-To: <20210330164207.3a2826f7@thinkpad> From: Yang Shi Date: Tue, 30 Mar 2021 09:53:01 -0700 Message-ID: Subject: Re: [PATCH 5/6] mm: migrate: don't split THP for misplaced NUMA page To: Gerald Schaefer Cc: Mel Gorman , "Kirill A. Shutemov" , Zi Yan , Michal Hocko , Huang Ying , Hugh Dickins , hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, Andrew Morton , Linux MM , linux-s390@vger.kernel.org, Linux Kernel Mailing List , Alexander Gordeev Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: C195DA000396 X-Stat-Signature: hxazjytfgo73zmz71hwqwnzc8im7rzp1 Received-SPF: none (gmail.com>: No applicable sender policy available) receiver=imf24; identity=mailfrom; envelope-from=""; helo=mail-ej1-f48.google.com; client-ip=209.85.218.48 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617123190-996356 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 Tue, Mar 30, 2021 at 7:42 AM Gerald Schaefer wrote: > > On Mon, 29 Mar 2021 11:33:11 -0700 > Yang Shi wrote: > > > The old behavior didn't split THP if migration is failed due to lack of > > memory on the target node. But the THP migration does split THP, so keep > > the old behavior for misplaced NUMA page migration. > > > > Signed-off-by: Yang Shi > > --- > > mm/migrate.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/mm/migrate.c b/mm/migrate.c > > index 86325c750c14..1c0c873375ab 100644 > > --- a/mm/migrate.c > > +++ b/mm/migrate.c > > @@ -1444,6 +1444,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > > int swapwrite = current->flags & PF_SWAPWRITE; > > int rc, nr_subpages; > > LIST_HEAD(ret_pages); > > + bool nosplit = (reason == MR_NUMA_MISPLACED); > > > > if (!swapwrite) > > current->flags |= PF_SWAPWRITE; > > @@ -1495,7 +1496,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > > */ > > case -ENOSYS: > > /* THP migration is unsupported */ > > - if (is_thp) { > > + if (is_thp && !nosplit) { > > This is the "THP migration is unsupported" case, but according to your > description you rather want to change the -ENOMEM case? > > Could this be the correct place to trigger THP split for NUMA balancing, > for architectures not supporting THP migration, like s390? Yes, I think it could be as I mentioned in the previous email. > > Do I understand it correctly that this change (for -ENOSYS) would > result in always failed THP migrations during NUMA balancing, if THP > migration was not supported? Yes.