From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 175D5E7717F for ; Mon, 16 Dec 2024 16:46:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4BB5A6B00A6; Mon, 16 Dec 2024 11:46:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 46A3F6B00A8; Mon, 16 Dec 2024 11:46:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 30C746B00AD; Mon, 16 Dec 2024 11:46:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 0D7696B00A6 for ; Mon, 16 Dec 2024 11:46:18 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id A1709C1277 for ; Mon, 16 Dec 2024 16:46:17 +0000 (UTC) X-FDA: 82901398650.19.7190B25 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf25.hostedemail.com (Postfix) with ESMTP id 80314A0012 for ; Mon, 16 Dec 2024 16:45:54 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sLGcVnQs; spf=pass (imf25.hostedemail.com: domain of "SRS0=f9gb=TJ=paulmck-ThinkPad-P17-Gen-1.home=paulmck@kernel.org" designates 139.178.84.217 as permitted sender) smtp.mailfrom="SRS0=f9gb=TJ=paulmck-ThinkPad-P17-Gen-1.home=paulmck@kernel.org"; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1734367561; h=from:from:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rJxeaUjkVrF5wmknojwOMYNDyN4MjrWy8F6SKzUh+Rk=; b=Guc+jEw/6RrdUle50ZW5vYlwhvZfSShiy9NmFM+nzu8PmFGdCTA3UQmfF4rspf7+T58swR 4YnzagBbQRkqBHlh8ceiEp3AiizIao6K4dAIG43VJ8/Jyz71CT6JNOtZaGH+zKXmCmDqHw vrVhqWoFRUmYgGXl9nGmolJD2LoHfdk= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1734367561; a=rsa-sha256; cv=none; b=J2za54rHYtEiOEpGeujEj1EMyiEeOBorky7spjc2AD9Sp4tMTdOSjKEeZLe3mXSuBnrBV8 u7inqi9uf1JFXabkm6B4BG+lRIJTQy5aTqmIfC2loO6Wck1TopjtmwB8XmMQXmkT/vi10w ckfuhNGt/TFFw+SsUafqpyrCEop+Wbw= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sLGcVnQs; spf=pass (imf25.hostedemail.com: domain of "SRS0=f9gb=TJ=paulmck-ThinkPad-P17-Gen-1.home=paulmck@kernel.org" designates 139.178.84.217 as permitted sender) smtp.mailfrom="SRS0=f9gb=TJ=paulmck-ThinkPad-P17-Gen-1.home=paulmck@kernel.org"; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 54F215C6398; Mon, 16 Dec 2024 16:45:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31C27C4CED0; Mon, 16 Dec 2024 16:46:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734367574; bh=wMjFHCnqbd1orATj6xhaCQkIQextYtaq2hJyyP4ZNRQ=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=sLGcVnQsF0yI9WZggA1XT3QI2IYOScA22yZxr8Wqcey6+m+ffDEpH3dtCeaM2iKQf TpvRbU4KV5S41JvMrxpybJTHWIaKDuIG2uYpT5SyTIbWmsjGdQnnXon/MRm8byLOBe m7eKbEHqZ+ilFu3PmcTnHZ3niQclKb5wgZHzhKjr7bU1tgdMFOVnxyUK4GLYkVTLCO POCNbI3dNr9lmCS96zbxlXVS64X4I7XilEkgHTcQZtZLreAdps5uPbKTWgZZ9Anq4d ZrxweBlwncNfj/lEsBl3CLgI28hHb5hjg8jQAJzFCz0SdoILQzmOOL/FgoQh/bNsHT qEvP7j1yDPU/g== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id CADB7CE0C4A; Mon, 16 Dec 2024 08:46:13 -0800 (PST) Date: Mon, 16 Dec 2024 08:46:13 -0800 From: "Paul E. McKenney" To: Uladzislau Rezki Cc: Vlastimil Babka , linux-mm@kvack.org, Andrew Morton , RCU , LKML , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Oleksiy Avramchenko Subject: Re: [PATCH v2 0/5] Move kvfree_rcu() into SLAB (v2) Message-ID: <5bb80786-220d-45d2-bd35-51876df4203c@paulmck-laptop> Reply-To: paulmck@kernel.org References: <20241212180208.274813-1-urezki@gmail.com> <17476947-d447-4de3-87bb-97d5f3c0497d@suse.cz> <6fb206de-0185-4026-a6f5-1d150752d8d0@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 80314A0012 X-Stat-Signature: p8zd9gfj4yrfznzh9kqxag4m4mxohtxk X-Rspam-User: X-HE-Tag: 1734367554-458546 X-HE-Meta: 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 SI51XgWN 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Dec 16, 2024 at 04:55:06PM +0100, Uladzislau Rezki wrote: > On Mon, Dec 16, 2024 at 04:44:41PM +0100, Vlastimil Babka wrote: > > On 12/16/24 16:41, Uladzislau Rezki wrote: > > > On Mon, Dec 16, 2024 at 03:20:44PM +0100, Vlastimil Babka wrote: > > >> On 12/16/24 12:03, Uladzislau Rezki wrote: > > >> > On Sun, Dec 15, 2024 at 06:30:02PM +0100, Vlastimil Babka wrote: > > >> >> On 12/12/24 19:02, Uladzislau Rezki (Sony) wrote: > > >> >> > Hello! > > >> >> > > > >> >> > This is v2. It is based on the Linux 6.13-rc2. The first version is > > >> >> > here: > > >> >> > > > >> >> > https://lore.kernel.org/linux-mm/20241210164035.3391747-4-urezki@gmail.com/T/ > > >> >> > > > >> >> > The difference between v1 and v2 is that, the preparation process is > > >> >> > done in original place instead and after that there is one final move. > > >> >> > > >> >> Looks good, will include in slab/for-next > > >> >> > > >> >> I think patch 5 should add more explanation to the commit message - the > > >> >> subthread started by Christoph could provide content :) Can you summarize so > > >> >> I can amend the commit log? > > >> >> > > >> > I will :) > > >> > > > >> >> Also how about a followup patch moving the rcu-tiny implementation of > > >> >> kvfree_call_rcu()? > > >> >> > > >> > As, Paul already noted, it would make sense. Or just remove a tiny > > >> > implementation. > > >> > > >> AFAICS tiny rcu is for !SMP systems. Do they benefit from the "full" > > >> implementation with all the batching etc or would that be unnecessary overhead? > > >> > > > Yes, it is for a really small systems with low amount of memory. I see > > > only one overhead it is about driving objects in pages. For a small > > > system it can be critical because we allocate. > > > > > > From the other hand, for a tiny variant we can modify the normal variant > > > by bypassing batching logic, thus do not consume memory(for Tiny case) > > > i.e. merge it to a normal kvfree_rcu() path. > > > > Maybe we could change it to use CONFIG_SLUB_TINY as that has similar use > > case (less memory usage on low memory system, tradeoff for worse performance). > > > Yep, i also was thinking about that without saying it :) Works for me as well! Thanx, Paul