From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 BAE561F4180; Tue, 2 Jun 2026 00:43:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780361031; cv=none; b=FhBO38TLgctlKSbYwdAZeUyI2wI6GngROw0tB+N/igXol2o+re2F914ZCcfRWSZedQgCDfOB8hrTsAiZtFszsMSq3iXLcGBv4Sn/i7FqBnPQobo99T9Q13dMLRdiCLGQoVq5NkpJcK3uwfQe5gYce20paNdy96JdeggvPDFlhOg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780361031; c=relaxed/simple; bh=EP7NbwxGQO3cHzJFzkZ79NTCvuSBMk7HVlXDF5Gk4gU=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=MzTvEF+P0CKyfd6EbS40pbppuskF6R5EWI9W5RuPZSaT6g29eAEZMyLPcQ73CmmTALD32JLe8ODnuXKtuO0qMkHPIrc9CrvGAM+cY2L7y6CJhk+x+49aHxMkD7NpOx4eYNbJIy0Efni1NK6Arw3gzmSZCCTW7wJR4M0rymfOfv4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=bFcb+93/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="bFcb+93/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1AA561F00893; Tue, 2 Jun 2026 00:43:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1780361030; bh=Rh2n9Gu0rmNTDcj9emYz6ha4zA22fi+waHRK2Lt+xYA=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=bFcb+93/9S95ynXbVnpuZtZBYT+X51bssv+rLmgGtRgV8B/W56LyHj9DX1uQVcj4i Pd6p0tFzPEmJGOLkLwCU38i7iM7tieX6PLvShLWnLmzImiLUxjSOP+AuXGeNX+RDxQ 9ziqdplU8XWD78fouW0PPprxDLqIHU3nxGZ3Rhqw= Date: Mon, 1 Jun 2026 17:43:49 -0700 From: Andrew Morton To: Chi Zhiling Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Matthew Wilcox (Oracle)" , Jan Kara , Hugh Dickins , Baolin Wang , Chi Zhiling Subject: Re: [PATCH v2 0/5] mm/shmem: optimize read with reduced xarray lookups and folio batching Message-Id: <20260601174349.e521b96acac805ac3d9bfbbb@linux-foundation.org> In-Reply-To: <20260601055704.167436-1-chizhiling@163.com> References: <20260601055704.167436-1-chizhiling@163.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit On Mon, 1 Jun 2026 13:56:59 +0800 Chi Zhiling wrote: > From: Chi Zhiling > > This series improves shmem read performance by implementing folio > batching in the read path and reducing unnecessary xarray lookups. > > Performance Results: > > fio --ioengine=sync --rw=read --bs=$1 --size=1G --runtime=180 --time_based --group_reporting --name=seq_read_test --filename=testfile > > | THP disabled in tmpfs | v7.1-rc5 | v7.1-rc5 + fbatch | Improvement | > | ---------------------- | ------------ | ----------------- | ----------- | > | 1M + normal file | bw=11.5GiB/s | bw=12.7GiB/s | +10.4% | > | 64k + normal file | bw=11.0GiB/s | bw=12.3GiB/s | +11.8% | > | 4k + normal file | bw=3826MiB/s | bw=3849MiB/s | +0.6% | > | 1M + fallocated file | bw=23.8GiB/s | bw=28.6GiB/s | +20.2% | > | 64k + fallocated file | bw=22.5GiB/s | bw=27.3GiB/s | +21.3% | > | 4k + fallocated file | bw=4655MiB/s | bw=4680MiB/s | +0.5% | > | 1M + hole | bw=24.2GiB/s | bw=28.6GiB/s | +18.2% | > | 64k + hole | bw=22.6GiB/s | bw=27.6GiB/s | +22.1% | > | 4k + hole | bw=4652MiB/s | bw=4489MiB/s | -3.5% | > > > | THP enabled in tmpfs | v7.1-rc5 | v7.1-rc5 + fbatch | Improvement | > | --------------------- | ------------ | ----------------- | ----------- | > | 1M + normal file | bw=13.7GiB/s | bw=13.9GiB/s | +1.4% | > | 64k + normal file | bw=13.5GiB/s | bw=13.5GiB/s | +0.0% | > | 4k + normal file | bw=3833MiB/s | bw=3859MiB/s | +0.7% | > | 1M + fallocated file | bw=24.9GiB/s | bw=34.2GiB/s | +37.3% | > | 64k + fallocated file | bw=23.0GiB/s | bw=31.4GiB/s | +36.5% | > | 4k + fallocated file | bw=4710MiB/s | bw=4655MiB/s | -1.2% | > | 1M + hole | bw=24.3GiB/s | bw=34.5GiB/s | +42.0% | > | 64k + hole | bw=23.5GiB/s | bw=31.1GiB/s | +32.3% | > | 4k + hole | bw=4690MiB/s | bw=4647MiB/s | -0.9% | > That looks nice. Microbenchmarks are useful, but are you able to help us understand how much benefit our users might see in real-world workloads? I'll take no action at this time - it's late in the cycle and reviewers have yet to participate. AI review flagged a few possible issues, so please take a look: https://sashiko.dev/#/patchset/20260601055704.167436-1-chizhiling@163.com