From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A9560233D6B for ; Fri, 8 Nov 2024 19:25:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731093939; cv=none; b=iDwNA7a5tltIMuD541aclO4JzlRy5OU4REOgPucHyXSp/GuyiI2IX7koLXnFCBCfFK6nODS4MMhdYTuIKt55Shs3/XcyQ3cGiIhqx67S4qaeiM8+thFf7LrDTEEyJm6YKL5d+FVXQWeWW0FRlKMiL3zvPcLDCoEw189NOa6GOJ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731093939; c=relaxed/simple; bh=MyD+tWxXFPgtNeJfGDjD4UfEb6QCKSOtoP60UxHsfTU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MBVNn9qU4VtaaF22QmqZNxTuR6Hn3AynCAw4UBtyvb5l/WzB109P87nT5w6mSrRV9JuRH3Na99TYQRxgiCbFhtAMDXsGuqOFLk7AkzRIoe7T5g5NrWMiuEr15Sp8xwvKFMAed/wLXMtjuMmRAyraWN4rFVfUySV2G2JMNfDF5uo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=qKZ2Tar+; arc=none smtp.client-ip=209.85.210.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="qKZ2Tar+" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-720c286bcd6so2272233b3a.3 for ; Fri, 08 Nov 2024 11:25:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1731093937; x=1731698737; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=dnt+jRFiZc1qVM1+yhnD5tvt36dLhBCo8c5G+kNMovs=; b=qKZ2Tar+HZbSxKSvP6Ocq1viEx5ncpolmaf7/vQNd9zFd3WAoSXlj/d03fmtdDzJXV NVcV6UW8tT7NTeBTgtDbRX2oMNw+XC7EhxRioi5jFczblSYVkiY8uinG0Wz9an9L7RQH BWU+kZSNLxlES8NNhiKvJOjYwmtizhDcj+M9cA12O5iI6s9xj3gsl2ZJSn4mxUPsbBL/ Jy7EYGUmMnZpEc6/9cytdueOOG9by3yLfTJuGBJ607MohKaziphQlK1AMd6MYHcNQkhn 6UCJ6rSsyEGafM41HBuSxoN2Wn8WsA9NdqDHfmhBhDLNO4oQ6KFjxnSRplx3vaZOLGVP m/0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731093937; x=1731698737; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=dnt+jRFiZc1qVM1+yhnD5tvt36dLhBCo8c5G+kNMovs=; b=ebwfU15cNnDdlIa6tQ+188PzgbdqLFQ3Hmpi0QfT+usn7ZCTq9yX1DP7wXbJzHcqOo Gj5XC/PFP9TulJav2GdjubPkjlD42WOtEdAt53chftmM7IOyqh6qJ9wugJsMnCfHyw0K u5KFykNPmDWAZQ3xmU5H2PqnXE1BJN+h95p3158m1lc3w/66RxSltUCaF+/3YsxKwm5t d1zc/5zXnGaRldUZSIWaM+dOivoEo0I0SM6ZRIerVojU+uOIrQLDx81pwoYGFThUh0cO S+Or0Y/jyJXsjSwOVBaEPIwJXNfYtPuqrCH67MgyvWaTsp9N9GIrqIq8NoIlMnBLW3Wo lnQA== X-Forwarded-Encrypted: i=1; AJvYcCWzU6CLPf9b8wxqFaEfRf+1tAgU2EaGqvyHo0mvB6apce7kEhT5Iqklftf8t3rz9lurQXC09UnZ1L0dpOQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yz5WscWWskDJQ1GoFFglgeui8nt0fatQ9R1Nkh2klISUkKBOTTQ MNsVK6kmUgfdqatAm3ec/q21eW5+6Tr6d55+tbEclW9XOhNmtJdE5wklYodlEZw= X-Google-Smtp-Source: AGHT+IELEroo6SHxpKCnpbZ7JYNo7XRYyZE04sY+1b30p170Yv7UDZgTSZ5/8jsynrXJsUDAnW5RlQ== X-Received: by 2002:a05:6a00:3a07:b0:71e:7b8a:5953 with SMTP id d2e1a72fcca58-7241338bdecmr5664070b3a.24.1731093936935; Fri, 08 Nov 2024 11:25:36 -0800 (PST) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-72407860a97sm4286553b3a.27.2024.11.08.11.25.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 Nov 2024 11:25:36 -0800 (PST) Message-ID: <07a6549a-6bbf-4e09-9e3b-128e779882a1@kernel.dk> Date: Fri, 8 Nov 2024 12:25:35 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 08/13] fs: add read support for RWF_UNCACHED To: Matthew Wilcox Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org References: <20241108174505.1214230-1-axboe@kernel.dk> <20241108174505.1214230-9-axboe@kernel.dk> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/8/24 11:33 AM, Matthew Wilcox wrote: > On Fri, Nov 08, 2024 at 10:43:31AM -0700, Jens Axboe wrote: >> +++ b/mm/swap.c >> @@ -472,6 +472,8 @@ static void folio_inc_refs(struct folio *folio) >> */ >> void folio_mark_accessed(struct folio *folio) >> { >> + if (folio_test_uncached(folio)) >> + return; >> if (lru_gen_enabled()) { > > This feels like it might be a problem. If, eg, process A is doing > uncached IO and process B comes along and, say, mmap()s it, I think > we'll need to clear the uncached flag in order to have things work > correctly. It's a performance problem, not a correctness problem. I'll take a look, should be fine to just unconditionally clear it here. uncached is a hint after all. We'll try our best to honor it, but there will be cases where inline reclaim will fail and you'll get cached contents, particularly if you mix uncached and buffered, or uncached and mmap. -- Jens Axboe