From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C56A71494C2 for ; Tue, 2 Dec 2025 01:33:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764639182; cv=none; b=b/azC310wlXn7OrFpsUhUez/LrkrtWs9U10lQTcB9sGGTANDceiIWaXBXgl10TyHRWKb4uI2WmaNj2DB7SPYvioD2e2RtMetXbHJ1kZkPM32KInbi1wDR6eAt3KooVp6Fl59Lc9eq7hYBMbhBueAjsfk2pXxt/CsJ6v0BgedAgA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764639182; c=relaxed/simple; bh=oe4l/S1/X9n/DZSGZd0YfLwRU+TB8ogHEYv9W6fZxDM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YuSDShMbw7yZyPORCqgAJ0H2CbNK1880LtP6eFPDCJFOI98QrqoUoDAsDxpUqkpeE7ZNmAEPUVKiR+Jt6YQtMN/XjBcXTDgL0nVKEY/SV6ZWnTNstRbVjjB9GqE2ZLVikCp9EI+Q1j/JxOFNkJYxCjoQt6MaQ/R5Z21sw3hHPmE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Bsb7incI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Bsb7incI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C379C116C6; Tue, 2 Dec 2025 01:33:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764639182; bh=oe4l/S1/X9n/DZSGZd0YfLwRU+TB8ogHEYv9W6fZxDM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Bsb7incIdQwV+qbtSrzI1R1Lf8ogfLheOc8H0ztMhA0RhnFaShC6xduKsj9g9yOH1 Vsv9IVe2mG39vW26gBS+TwZLbBcXVMZD+OCF2gUiE5S207/NKCOa0E5X0pnZWWJoHs 3/nF6Qd4zY39/v/CPOrXw4SOihVHe9GUh52r5L2fTqWNyY0+jGPZ4t4903SQTpwoOq wznbIaBikJqPcmTutHBTQSHSXUtfroBY7jtFjHfziILFcNHSFrOeqq6QYWAlh+J/BV MiBQC0a/PkJbRzXCeC9dBaid3nScJUqdw4fYOIyYeyapRz6PWg2Y+YP+nUNsaaVVSp 4voBa+5GpvLFg== Date: Tue, 2 Dec 2025 01:33:01 +0000 From: Jaegeuk Kim To: Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org Subject: Re: [PATCH 3/4] mm/readahead: add a_ops->ra_folio_order to get a desired folio order Message-ID: References: <20251201210152.909339-1-jaegeuk@kernel.org> <20251201210152.909339-4-jaegeuk@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@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 12/01, Matthew Wilcox wrote: > On Mon, Dec 01, 2025 at 09:24:41PM +0000, Jaegeuk Kim wrote: > > On 12/01, Matthew Wilcox wrote: > > > On Mon, Dec 01, 2025 at 09:01:26PM +0000, Jaegeuk Kim wrote: > > > > This patch introduces a new address operation, a_ops->ra_folio_order(), which > > > > proposes a new folio order based on the adjusted order for page_cache_sync_ra. > > > > > > > > Hence, each filesystem can set the desired minimum order of folio allocation > > > > when requesting fadvise(POSIX_FADV_WILLNEED). > > > > > > Again, you've said what but not why. Does the mm code not ramp up the > > > folio order sufficiently quickly? What are you trying to accomplish? > > > > That's why I posted a series of the patches to provide more details. Could you > > please check the last patch in the series to show fadvise() does not increase > > the folio order? > > > > https://lore.kernel.org/linux-f2fs-devel/20251201210152.909339-5-jaegeuk@kernel.org/T/#u > > So what you're trying to say is that readahead() currently only uses > order-0 pages and you want it to use larger order pages? I agree with > that! But I don't think this is the way to do it. We should just use > larger order allocations, always. None of this "call the filesystem, > check a sysfs parameter". Just use the largest order page that fits. I got that, and posted v2. Thanks,