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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CF20C433EF for ; Tue, 15 Mar 2022 22:58:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CB88E8D0002; Tue, 15 Mar 2022 18:58:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C67818D0001; Tue, 15 Mar 2022 18:58:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B561E8D0002; Tue, 15 Mar 2022 18:58:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0040.hostedemail.com [216.40.44.40]) by kanga.kvack.org (Postfix) with ESMTP id A6F7A8D0001 for ; Tue, 15 Mar 2022 18:58:33 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 41F911821CC0B for ; Tue, 15 Mar 2022 22:58:33 +0000 (UTC) X-FDA: 79248136506.17.17A31FB Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) by imf13.hostedemail.com (Postfix) with ESMTP id 903542000E for ; Tue, 15 Mar 2022 22:58:32 +0000 (UTC) Received: by mail-pl1-f178.google.com with SMTP id w4so340257ply.13 for ; Tue, 15 Mar 2022 15:58:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=tpBIy3wDvQGfwH9ls4xR2jLiqxVzU1kgqh+8V0SkolM=; b=qhVli5fhBKxbJaOS2y1VJDUNLLAHqtWf2jL00Tb9InM7nKWn4akLb4Dppd9KqCQKqi 29cdJh6WElt9yN+hN0MGEAy86fyKb97KzWJeXa5y5Py0+U53ADdqfSOIUXPz/3KD0aCx LYg309WkcuTmxoUEewGSXr5AmEYfaMpG17srZRwbk1T6+BZTFGLsmTPDE4D11BJMD5lF 7qtxuk/B1mwpl/dYL30r5UXrw4xtVlhwUSI9lz/0KcxWl9SWxD02iBLzrQqIOYNa3U0a 8tzs9T/kBvbHrxh92yWpOTQmjEta9rsFny/9HualjYsEDQlNDdMilYFxEO84SAEQjnO9 OffQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=tpBIy3wDvQGfwH9ls4xR2jLiqxVzU1kgqh+8V0SkolM=; b=Eo9ytHmE5h3Pk8pbPajVYyvbNzaR884b0kS+SJ3I4ZWdzmll/Jsi6RvZN8dMcb1S9Q a9J3eZKBU37wV54sHADJA4QNfogyihslTvzfiiEN4eKqy6O8GZlojECUXxgs4EYWh86U KBjsIp2cb3ipwAXM2hWtEtxgbwYh79hmEwdzP+jWLXewaOQkCN3j4cWye3Ewzi/jFpz2 1H94DTEkC1N9uLUf364TJ2Dm2tHV0otfpprZ7Ojl2WOeyBF0r9MYZFAiW8xBymaSvQdJ 8qIUfA5pKyGpXn9uDmzIYLr0w/1R/SAb38cpVCpyxpBva+qUjgNvHXRO4KdUW1JmRA+J EyRg== X-Gm-Message-State: AOAM530jhiZwzgj4XwDayWngA5Qlm9ufnmMbVDOOq4vWiXVbqkUPqbBX pUaIW9EnEdjSf9E4HnK+gBE= X-Google-Smtp-Source: ABdhPJzvr4L3c32sdszzPbBKgCVWu3n+sX8w08P6WyBLH8X2gU41vVQJ2efLIV0AJFg2T4fNGpVv0A== X-Received: by 2002:a17:90b:4c41:b0:1be:f5d3:78eb with SMTP id np1-20020a17090b4c4100b001bef5d378ebmr7001311pjb.187.1647385111454; Tue, 15 Mar 2022 15:58:31 -0700 (PDT) Received: from google.com ([2620:15c:211:201:7484:dc22:fe49:91cb]) by smtp.gmail.com with ESMTPSA id k3-20020a056a00168300b004f7e60da26csm139387pfc.182.2022.03.15.15.58.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Mar 2022 15:58:30 -0700 (PDT) Date: Tue, 15 Mar 2022 15:58:28 -0700 From: Minchan Kim To: Charan Teja Kalla Cc: akpm@linux-foundation.org, surenb@google.com, vbabka@suse.cz, rientjes@google.com, sfr@canb.auug.org.au, edgararriaga@google.com, nadav.amit@gmail.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "# 5 . 10+" Subject: Re: [PATCH V2,2/2] mm: madvise: skip unmapped vma holes passed to process_madvise Message-ID: References: <4f091776142f2ebf7b94018146de72318474e686.1647008754.git.quic_charante@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4f091776142f2ebf7b94018146de72318474e686.1647008754.git.quic_charante@quicinc.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 903542000E X-Stat-Signature: rgm8rfayaz5aeskigisi383yu5ux6u5b Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=qhVli5fh; spf=pass (imf13.hostedemail.com: domain of minchan.kim@gmail.com designates 209.85.214.178 as permitted sender) smtp.mailfrom=minchan.kim@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none) X-Rspam-User: X-HE-Tag: 1647385112-348928 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 Fri, Mar 11, 2022 at 08:59:06PM +0530, Charan Teja Kalla wrote: > The process_madvise() system call is expected to skip holes in vma > passed through 'struct iovec' vector list. But do_madvise, which > process_madvise() calls for each vma, returns ENOMEM in case of unmapped > holes, despite the VMA is processed. > Thus process_madvise() should treat ENOMEM as expected and consider the > VMA passed to as processed and continue processing other vma's in the > vector list. Returning -ENOMEM to user, despite the VMA is processed, > will be unable to figure out where to start the next madvise. > Fixes: ecb8ac8b1f14("mm/madvise: introduce process_madvise() syscall: an external memory hinting API") > Cc: # 5.10+ Hmm, not sure whether it's stable material since it changes semantic of API. It would be better to change the semantic from 5.19 with man page update to specify the change. > Signed-off-by: Charan Teja Kalla > --- > Changes in V2: > -- Fixed handling of ENOMEM by process_madvise(). > -- Patch doesn't exist in V1. > > mm/madvise.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index e97e6a9..14fb76d 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -1426,9 +1426,16 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, > > while (iov_iter_count(&iter)) { > iovec = iov_iter_iovec(&iter); > + /* > + * do_madvise returns ENOMEM if unmapped holes are present > + * in the passed VMA. process_madvise() is expected to skip > + * unmapped holes passed to it in the 'struct iovec' list > + * and not fail because of them. Thus treat -ENOMEM return > + * from do_madvise as valid and continue processing. > + */ > ret = do_madvise(mm, (unsigned long)iovec.iov_base, > iovec.iov_len, behavior); > - if (ret < 0) > + if (ret < 0 && ret != -ENOMEM) > break; > iov_iter_advance(&iter, iovec.iov_len); > } > -- > 2.7.4 >