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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 399E2C433B4 for ; Wed, 19 May 2021 19:48:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11F85611BD for ; Wed, 19 May 2021 19:48:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232231AbhESTtz (ORCPT ); Wed, 19 May 2021 15:49:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43182 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232212AbhESTtx (ORCPT ); Wed, 19 May 2021 15:49:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621453713; h=from:from:reply-to:subject:subject: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=l8/USwElDF6oj5/aVhPUN8/jUy5vgh63dDs+ZspH7HI=; b=glVi1EL0p49Uv73zTyAciufUO18VszD5dRU1NYq9q+beOTj603FWUR2G7Da3EJirBuOVMo YydgbwkU0Tr7F8oUAFfYmPzndchcfJbYfxiK9j9abGB2EXPSlE8JtAq/5OleY5+slsvgVK nH1SIG2uErmtfeE/hxSv1nIsRcGX0Go= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-173-kDviJu_KOeC7lGiQF49XVA-1; Wed, 19 May 2021 15:48:31 -0400 X-MC-Unique: kDviJu_KOeC7lGiQF49XVA-1 Received: by mail-wr1-f70.google.com with SMTP id 93-20020adf80e60000b0290106fab45006so7602224wrl.20 for ; Wed, 19 May 2021 12:48:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=l8/USwElDF6oj5/aVhPUN8/jUy5vgh63dDs+ZspH7HI=; b=qA0BAtcu1sjd2jAuqmZmPV7/RGKftQe8cpZ2f8HEFh1feN7f+2SlDjboCDFHXcDJbb mypeLkcGRpfxog1iqyEirtdxPdQc1KueBWAdeGSgZwnWRvbgvMbGNBRAMVyYRPGtEEl3 bBIkZ6D/47/8OR3CQyjIwv/60gwyShApn4IwZIg4nmoAex//S2gjuP/J9P7mp6TXDbP2 mDttgQHBdwPGQeheGLzSXHR3o6/D/Vw6jnUJoCSHkBerH94AonL21EwMNlWGP1TCFXFo LAQL3rQRGcyqXXsqKa7IgNKbXM9KaLnvn1fCxDn2u+GHCw6ugz5F0/IiN635EugRq0Fz dBzg== X-Gm-Message-State: AOAM53014ZIoxEoTvsJPDwm06vXVdRrSccpRBNokIQf9UMhNRwfz6zv5 3V9R5/cpwwFHUIJL9OosFFQlNfQkWdmzt6J3MpFsufihKQTnmBlOuKEHvZGcFtqW6v4h+4Di/sF vNKqNu64P5XeT2zYrQL1dDvk= X-Received: by 2002:a1c:e156:: with SMTP id y83mr722847wmg.89.1621453710316; Wed, 19 May 2021 12:48:30 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy3ab8RbkH5w4sabhmqxCp0dpZ3QX7ubr6x9WwGVuiP/WtqOKaUqk1cpJRCsR9S4Dvrp4ch8w== X-Received: by 2002:a1c:e156:: with SMTP id y83mr722841wmg.89.1621453710154; Wed, 19 May 2021 12:48:30 -0700 (PDT) Received: from localhost (cpc111743-lutn13-2-0-cust979.9-3.cable.virginm.net. [82.17.115.212]) by smtp.gmail.com with ESMTPSA id r11sm440744wrp.46.2021.05.19.12.48.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 May 2021 12:48:29 -0700 (PDT) Date: Wed, 19 May 2021 20:48:29 +0100 From: Aaron Tomlin To: Matthew Wilcox Cc: linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, mhocko@suse.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/page_alloc: bail out on fatal signal during reclaim/compaction retry attempt Message-ID: <20210519194829.sess6lhfzlmccpdu@ava.usersys.com> X-PGP-Key: http://pgp.mit.edu/pks/lookup?search=atomlin%40redhat.com X-PGP-Fingerprint: 7906 84EB FA8A 9638 8D1E 6E9B E2DE 9658 19CC 77D6 References: <20210519192321.3247175-1-atomlin@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2021-05-19 20:32 +0100, Matthew Wilcox wrote: > On Wed, May 19, 2021 at 08:23:21PM +0100, Aaron Tomlin wrote: > > +++ b/mm/page_alloc.c > > @@ -4252,6 +4252,9 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, > > if (!order) > > return false; > > > > + if (fatal_signal_pending(current)) > > + goto out; > > I think 'goto out' will be confusing. It'll output a tracepoint, which > isn't going to record that a fatal signal is pending, so it'll cause > some head scratching for someone looking through the traces. I > think we should just return false here and skip the tracepoint. I agree. Having said this, I do plan to send a patch to illustrate why compaction should not retry to avoid possible confusion. Nevertheless, I am happy to modify as per your request. Kind regards, -- Aaron Tomlin