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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 0A28DC43464 for ; Mon, 21 Sep 2020 11:44:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7FB52151B for ; Mon, 21 Sep 2020 11:44:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="pC3qQ1xt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726973AbgIULoO (ORCPT ); Mon, 21 Sep 2020 07:44:14 -0400 Received: from z5.mailgun.us ([104.130.96.5]:51234 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726951AbgIULoG (ORCPT ); Mon, 21 Sep 2020 07:44:06 -0400 X-Greylist: delayed 301 seconds by postgrey-1.27 at vger.kernel.org; Mon, 21 Sep 2020 07:44:05 EDT DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1600688645; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=aj7+moQI0HWZLSMQvc/earvkxmxlSTsYW5THyyMnfSg=; b=pC3qQ1xtn0g/sbQtGrP0plCZfYIxklGQGHRRVFL3j6TvwzTVCINKA3KdRb0igASxrlN62IRx D1Rcfj0hGqDRabuZQ3HoUI5s1liEMTxV6/VaW8rV5E0g7d9my1Xu1I3RJaBHjtO8qyjJSmmX 5UN0ya777B5o4b0Vw7cw+CuBJvM= X-Mailgun-Sending-Ip: 104.130.96.5 X-Mailgun-Sid: WyIxOTQxNiIsICJsaW51eC1mc2RldmVsQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n03.prod.us-west-2.postgun.com with SMTP id 5f6890d44ab73023a792e0be (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 21 Sep 2020 11:39:00 GMT Sender: ppvk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id DDCE2C433F1; Mon, 21 Sep 2020 11:39:00 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: ppvk) by smtp.codeaurora.org (Postfix) with ESMTPSA id 9F189C433CB; Mon, 21 Sep 2020 11:39:00 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 21 Sep 2020 17:09:00 +0530 From: ppvk@codeaurora.org To: Matthew Wilcox Cc: miklos@szeredi.hu, linux-fsdevel@vger.kernel.org, stummala@codeaurora.org, sayalil@codeaurora.org Subject: Re: [PATCH V2] fuse: Remove __GFP_FS flag to avoid allocator recursing In-Reply-To: <20200916145634.GN5449@casper.infradead.org> References: <1600238380-33350-1-git-send-email-ppvk@codeaurora.org> <20200916145634.GN5449@casper.infradead.org> Message-ID: <2a5b17f0a80d6a52e6c2c7301dea4c41@codeaurora.org> X-Sender: ppvk@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 2020-09-16 20:26, Matthew Wilcox wrote: > On Wed, Sep 16, 2020 at 12:09:40PM +0530, Pradeep P V K wrote: >> Changes since V1: >> - Used memalloc_nofs_save() in all allocation paths of fuse daemons >> to avoid use __GFP_FS flag as per Matthew comments. > > That's not how to use memalloc_nofs_save(). You call it when entering > a > context in which any memory allocation would cause a deadlock. You > don't > look for every place which allocates memory and wrap the memory > allocation > calls in memalloc_nofs_save() because you're likely to miss one. > ok, i will fix this in my next patch set. >> static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) >> { >> + ssize_t size; >> + unsigned nofs_flag; > > This is almost certainly too low in the call stack. ok, i will update this in my next patch set.