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=-3.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 78720C4363C for ; Thu, 8 Oct 2020 06:04:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03EB121897 for ; Thu, 8 Oct 2020 06:04:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="I//eiam6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728363AbgJHGE2 (ORCPT ); Thu, 8 Oct 2020 02:04:28 -0400 Received: from m42-4.mailgun.net ([69.72.42.4]:18723 "EHLO m42-4.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726245AbgJHGE1 (ORCPT ); Thu, 8 Oct 2020 02:04:27 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1602137067; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=q0WJO/0dJ8BgShdei2F0Ls8cHIZgFMJNnmLdHmZqEgE=; b=I//eiam6y2rv6M+oTW+UCIq3wzYntQr/B1wcHYeGMH5ttMghkJ+c+WKfxvP7liv2oxV1HJPy Kx1qtCLuwQj/EVvvY8eqXTjmbeQ1qvbC4f6HLqqfV8MYwKO5o+B8X7hLq5ezR9xALwAAcFpH 1z6/LycLZ4+qtpj+ASC1KtdtKMQ= X-Mailgun-Sending-Ip: 69.72.42.4 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-n01.prod.us-west-2.postgun.com with SMTP id 5f7eabb5856d9308b5b5ca54 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 08 Oct 2020 06:03:33 GMT Sender: ppvk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id D1524C433FF; Thu, 8 Oct 2020 06:03:33 +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 251F1C433CB; Thu, 8 Oct 2020 06:03:33 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 08 Oct 2020 11:33:33 +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 V3] fuse: Remove __GFP_FS flag to avoid allocator recursing In-Reply-To: <077d4fc0e56db4f4433542e9fe971190@codeaurora.org> References: <1600840675-43691-1-git-send-email-ppvk@codeaurora.org> <20200923124914.GO32101@casper.infradead.org> <077d4fc0e56db4f4433542e9fe971190@codeaurora.org> Message-ID: 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 2020-09-24 20:26, ppvk@codeaurora.org wrote: > On 2020-09-23 18:19, Matthew Wilcox wrote: >> On Wed, Sep 23, 2020 at 11:27:55AM +0530, Pradeep P V K wrote: >>> Changes since V2: >>> - updated memalloc_nofs_save() to allocation paths that potentially >>> can cause deadlock. >> >> That's the exact opposite of what I said to do. Again, the *THREAD* >> is the thing which must not block, not the *ALLOCATION*. So you >> set this flag *ON THE THREAD*, not *WHEN IT DOES AN ALLOCATION*. >> If that's not clear, please ask again. > > The fuse threads are created and started in external libfuse userspace > library functions but not in Kernel. The lowest entry point for these > threads > to enter in kernel is fuse_dev_read()/fuse_dev_splice_read(). > > So, can we suppose to use memalloc_nofs_save() from > external userspace library functions ? > > Even if we used, can you confirm, if the context of > memalloc_nofs_save() > can be persist in kernel ? (when the thread enters into kernel space). > > Also, i didn't see memalloc_nofs_save() been used/called from any > external userspace library functions. > > > Thanks and Regards, > Pradeep Friendly Reminder !!