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 A42AF8462; Thu, 27 Mar 2025 21:46:46 +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=1743112006; cv=none; b=ow7SO+T/Kk7cWB87dtzNQtY7XcNf7Hc0V/pxL5Fj5/TRTNnG6FYMmTWxMwrqTMQxHAJbbL+zwcEftedbkqI1/czCh+2O/EOy2YiV0LTUOyAt6LqrfBzLcCdyXINTKBr5J4kgxCIie3vWqWsAV+NTJkxojlfMZx+gx3aSz/nci3U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743112006; c=relaxed/simple; bh=044NMnypJBKDHzV54PkNfkWM1PAfOVt5sNmhyUdaFz8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JaNkzehRHK+8F1f4WcLOb4rM2SHWrEUa/WeggmBc5f4nvouESylVw0FZaXHGBhjBK0RMoYyC+spuibiRqFOxK2QxFNzq6jwbyoxytyEg2XM6sjnoIOuSG+ciS1FJw//6+ev0xypFpm5mNyGzCbkdE/oWoBrQkx3vAoeVD2K4/FU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PbrjDgJ4; 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="PbrjDgJ4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D4EFC4CEDD; Thu, 27 Mar 2025 21:46:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743112006; bh=044NMnypJBKDHzV54PkNfkWM1PAfOVt5sNmhyUdaFz8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PbrjDgJ4+NfAozJ7lqUyl/lBGtxzqX4FdqXvsbkLlWVlzKiNBfvv149fKViJAbrER 5CtC9il1MqDLyz8I+p1kXiPFoz/CM9Nhcz/IX3D4UQSkykxPycZSr9Pi7jpc660yUL V6UyTrNzKm1mzyTeNkpZsi+y7JCsoe1BvdEWYlTU5niHpJ1/r4mogyHZJZvWD+VuUV xO8+ZystdjlkOMfDt9ox3odkNMIpmJ+5CdmMH7QpGTbv0AJ4aho7RMV+6L/Cl+c2WA TZV0g/0RPt5SvtM/IdTaZxRlNVhyJSy48fNnsreUpmVUtNBrTvwejGc7HOZfnXi5jU zhyBn2nGlwvyg== Date: Thu, 27 Mar 2025 14:46:44 -0700 From: Luis Chamberlain To: Dave Chinner Cc: lsf-pc@lists.linux-foundation.org, patches@lists.linux.dev, fstests@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, oliver.sang@intel.com, hannes@cmpxchg.org, willy@infradead.org, jack@suse.cz, apopple@nvidia.com, brauner@kernel.org, hare@suse.de, oe-lkp@lists.linux.dev, lkp@intel.com, john.g.garry@oracle.com, p.raghav@samsung.com, da.gomez@samsung.com, dave@stgolabs.net, riel@surriel.com, krisman@suse.de, boris@bur.io, jackmanb@google.com, gost.dev@samsung.com Subject: Re: [LSF/MM/BPF Topic] synthetic mm testing like page migration Message-ID: References: Precedence: bulk X-Mailing-List: linux-fsdevel@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 Thu, Mar 27, 2025 at 07:46:03AM +1100, Dave Chinner wrote: > On Wed, Mar 26, 2025 at 11:59:48AM -0700, Luis Chamberlain wrote: > > I'd like to propose this as a a BoF for MM. > > > > We can find issues if we test them, but some bugs are hard to reproduce, > > specially some mm bugs. How far are we willing to add knobs to help with > > synthetic tests which which may not apply to numa for instance? An > > example is the recent patch I just posted to force testing page > > migration [0]. We can only run that test if we have a numa system, and a > > lot of testing today runs on guests without numa. Would we be willing > > to add a fake numa node to help with synthetic tests like page > > migration? > > Boot your test VMs with fake-numa=4, and now you have a 4 node > system being tested even though it's not a real, physical numa > machine. I've been doing this for the best part of 15 years now > with a couple of my larger test VMs explicitly to test NUMA > interactions. Suuuuweet! Given your long term use of it, we'll just make it a default for all kdevops libvirt testing now! > One of the eventual goals of check-parallel is to have all these > things environmental variables like memory load, compaction, cpu > hotplug, etc to be changing in the background whilst the tests > running so that we can exercise all the filesystem functionality > under changing MM and environmental conditions without having to > code that into individual tests.... Indeed, I have high hopes for check-parallel. Luis