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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 445CFCAC5AE for ; Fri, 26 Sep 2025 10:08:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6EA998E0005; Fri, 26 Sep 2025 06:08:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6C0E68E0001; Fri, 26 Sep 2025 06:08:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5B0248E0005; Fri, 26 Sep 2025 06:08:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 487238E0001 for ; Fri, 26 Sep 2025 06:08:32 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id E1D8C11A834 for ; Fri, 26 Sep 2025 10:08:31 +0000 (UTC) X-FDA: 83930976822.07.1FC55F6 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by imf13.hostedemail.com (Postfix) with ESMTP id BF13320014 for ; Fri, 26 Sep 2025 10:08:28 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=HKFgXozA; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=kQnVrAQP; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=HKFgXozA; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=kQnVrAQP; spf=pass (imf13.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758881309; h=from:from:sender: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Ql9sJWg0tZNaVxk76MXuMAFIJmAUgI2uAUBYEZyDzyg=; b=DH7/2ik9bh5st3Y/u+NjSQR5B7HMZmP7PMH38lkB9ZAvBQppqKkvFXVNCOE06jhqlpteJ1 nsI8sB71qqsoM9tN6SvgN/AO9fUx2Pm8rFM3jSgp2mwOSNiZ0ZS5qAH8HNzSuS50x+xvYm mpqAA1fmeGROghqdxZHP3kjrWpxUEFU= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=HKFgXozA; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=kQnVrAQP; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=HKFgXozA; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=kQnVrAQP; spf=pass (imf13.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1758881309; a=rsa-sha256; cv=none; b=1wAK6wD9WxlPhUDPePx8lBwylpfDSIX34L6xstfc09tvcvnD8xvNCEodGgEl/7fERPptY1 YL7GSVQ1n1O8RrAk3HMvdlWQ37hQSwLgxWV6NqQAQ5ibpQxdW8oFig4l7lh/uhX9gSpx9t wVxUE5yYBGD63gkpCRUGYI+abtkvGX8= Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8440B6AFAC; Fri, 26 Sep 2025 10:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1758881306; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=Ql9sJWg0tZNaVxk76MXuMAFIJmAUgI2uAUBYEZyDzyg=; b=HKFgXozAba1H2yA32avvlwJ9Q66kjQ0ETPT9nX1Sq1ca662pY0w1um7zc68yNF0nRexnaf BZ1hD0s+xpEMWJstPonsuqupTxNVTdnwK3SaKYrEngMJbmAaqEBk+n1avXvTVbA63mCuod QTdX5g34O3rQb1sFcBUXvmQcFPgvBh4= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1758881306; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=Ql9sJWg0tZNaVxk76MXuMAFIJmAUgI2uAUBYEZyDzyg=; b=kQnVrAQPZCGhxYOMLLrpBSHnw77JSJnWJ1Os69YYHUeoPbVrYMQkWjiOJNa77MPZcia2cW 3evCK9oqrEj+ckBA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1758881306; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=Ql9sJWg0tZNaVxk76MXuMAFIJmAUgI2uAUBYEZyDzyg=; b=HKFgXozAba1H2yA32avvlwJ9Q66kjQ0ETPT9nX1Sq1ca662pY0w1um7zc68yNF0nRexnaf BZ1hD0s+xpEMWJstPonsuqupTxNVTdnwK3SaKYrEngMJbmAaqEBk+n1avXvTVbA63mCuod QTdX5g34O3rQb1sFcBUXvmQcFPgvBh4= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1758881306; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=Ql9sJWg0tZNaVxk76MXuMAFIJmAUgI2uAUBYEZyDzyg=; b=kQnVrAQPZCGhxYOMLLrpBSHnw77JSJnWJ1Os69YYHUeoPbVrYMQkWjiOJNa77MPZcia2cW 3evCK9oqrEj+ckBA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 6160E1373E; Fri, 26 Sep 2025 10:08:26 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id CnB0Fxpm1miVFwAAD6G6ig (envelope-from ); Fri, 26 Sep 2025 10:08:26 +0000 Message-ID: <80f8bdf8-ce50-4682-9468-9f38e0817e89@suse.cz> Date: Fri, 26 Sep 2025 12:08:26 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 04/23] slab: add sheaf support for batching kfree_rcu() operations Content-Language: en-US To: Suren Baghdasaryan Cc: Harry Yoo , "Liam R. Howlett" , Christoph Lameter , David Rientjes , Roman Gushchin , Uladzislau Rezki , Sidhartha Kumar , linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcu@vger.kernel.org, maple-tree@lists.infradead.org, "Paul E . McKenney" References: <20250910-slub-percpu-caches-v8-0-ca3099d8352c@suse.cz> <20250910-slub-percpu-caches-v8-4-ca3099d8352c@suse.cz> <6f92eca3-863e-4b77-b2df-dc2752c0ff4e@suse.cz> <40461105-a344-444f-834b-9559b6644710@suse.cz> From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Action: no action X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: BF13320014 X-Stat-Signature: zeuba4uc17gbxp45rg6xczzh3yy58huf X-HE-Tag: 1758881308-859580 X-HE-Meta: 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 OaET9vUV ujQVQPR6eY1/+GB2Lefytk0sZqJcsraRrj60u5qTuPVC+yNYA2FuQoSU7qByhwjrj+0SNVZAQmfRMC+Smn24UF16VWS4vETFl4D+vO4DpumittfOmHcnQeMvsqjzUuIz+4BjwbU4/gpnnCGxWk052/V7wdYWMaHvFfCxKdq/GzlJdt/ieOvLLqOWMkiI8gGT7GJp7k2K/CPfkFa4dNX4doZyuEvNpfqGZHFMVRT59B0Esz4fsg9xWqpnedIAhLNb/QA2nVaseDzBeDXY/lw4RipNwfsAtPwc60qj0KkbvSNE/s2ZnaLM9ptxn37iNcBY+oUgh 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 9/25/25 06:35, Suren Baghdasaryan wrote: > On Thu, Sep 18, 2025 at 1:09 AM Vlastimil Babka wrote: >> >> Expected advantages: >> - batching the kfree_rcu() operations, that could eventually replace the >> existing batching >> - sheaves can be reused for allocations via barn instead of being >> flushed to slabs, which is more efficient >> - this includes cases where only some cpus are allowed to process rcu >> callbacks (Android) > > nit: I would say it's more CONFIG_RCU_NOCB_CPU related. Android is > just an instance of that. OK changed that. Changes due to your other suggestions: diff --git a/mm/slub.c b/mm/slub.c index 8220ce095970..fec0cdc7ef37 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3945,15 +3945,12 @@ void flush_all_rcu_sheaves(void) */ INIT_WORK(&sfw->work, flush_rcu_sheaf); - sfw->skip = false; sfw->s = s; queue_work_on(cpu, flushwq, &sfw->work); } for_each_online_cpu(cpu) { sfw = &per_cpu(slub_flush, cpu); - if (sfw->skip) - continue; flush_work(&sfw->work); } @@ -5643,6 +5640,10 @@ bool __kfree_rcu_sheaf(struct kmem_cache *s, void *obj) rcu_sheaf = pcs->rcu_free; + /* + * Since we flush immediately when size reaches capacity, we never reach + * this with size already at capacity, so no OOB write is possible. + */ rcu_sheaf->objects[rcu_sheaf->size++] = obj; if (likely(rcu_sheaf->size < s->sheaf_capacity))