From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE26E24CEF9; Mon, 10 Feb 2025 21:18:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739222289; cv=none; b=VeSQW1PnhqMp5YQrOJk7ja2TjdkZonsH57xILoaax3Yf++hVDOe45W98UL9R8EAFwErOdRspZ210SOkbCCF+24gozWs+Zw+1HkhBa7OZEiaof9BzI6WJdMpDqJwsD4HhO0fDQ52cf3YMG9JSoEVcJBBRdu70yQflk8gkZGDhrnM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739222289; c=relaxed/simple; bh=FqFgLXXsWXWhhqPFJsoFGXHoF0ZClHSi4272/zYwWJ0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=r5JkIrsxTy/KBFuUhMSmADjCRiGCS96gjbp+pXvsOtoW73xxskJJtRxwjj+YHNinjwMYqX87aqmI0k9jFt8mIhQg8sjQfKhGsk26jRklQPRXn2/epLtz5SGmhMRBnffaNcYdfivz1N6EfcR6YcDGgg01nS8PJeSBCpC2qJx0dYY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=t97e1HkA; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="t97e1HkA" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=GrlnFGpTcpJHCevQurfmbvgrKTwhzhcmfTdnYrE4ibo=; b=t97e1HkAox5QN0FLIyIeq2exVs fNXQoKT2xnLU9hq01Pm8bHhbRiEIb3VPUqtADDs4T5xFWweQ9C+WAptWLuHbXKs1LCEq8KVMstqHS itl4c2oNuCT4jWChinvOLxrUiZ2ORAE1Sq3MpdHBTAXn9nnwDCCE6jP5+xcq595s3wJ32wX78Ekan U57P6N30p8LMIITW/AkzhvDt60KarhszJowEw34KladrLUc9H+XaHzq0p4iNGm4TxjEZar0EbXELC xAZAC3js7tMDnPm56iJfWjNWcpcToIMtQOqkVHwSLdNFoPMUubq2SWetqQ3Cp1AcBiFTshuer8aqD qglLbrNQ==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1thbAK-0000000Gmuv-2i7Q; Mon, 10 Feb 2025 21:18:04 +0000 Date: Mon, 10 Feb 2025 21:18:04 +0000 From: Matthew Wilcox To: Dave Chinner Cc: "Raphael S. Carvalho" , linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, djwong@kernel.org, hch@lst.de, Avi Kivity Subject: Re: Possible regression with buffered writes + NOWAIT behavior, under memory pressure Message-ID: References: Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Feb 11, 2025 at 08:09:31AM +1100, Dave Chinner wrote: > Better to only do the FGP_NOWAIT check when a failure occurs; that > puts it in the slow path rather than having to evaluate it > unnecessarily every time through the function/loop. i.e. > > folio = filemap_alloc_folio(gfp, order); > - if (!folio) > - return ERR_PTR(-ENOMEM); > + if (!folio) { > + if (fgp_flags & FGP_NOWAIT) > + err = -EAGAIN; > + else > + err = -ENOMEM; > + continue; > + } Or would we be better off handling ENOMEM the same way we handle EAGAIN? eg something like: +++ b/io_uring/io_uring.c @@ -1842,7 +1842,7 @@ void io_wq_submit_work(struct io_wq_work *work) do { ret = io_issue_sqe(req, issue_flags); - if (ret != -EAGAIN) + if (ret != -EAGAIN || ret != -ENOMEM) break; /*