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 C1479C021B8 for ; Wed, 26 Feb 2025 19:28:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C04C280001; Wed, 26 Feb 2025 14:28:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 170126B0095; Wed, 26 Feb 2025 14:28:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F2B5C280001; Wed, 26 Feb 2025 14:28:45 -0500 (EST) 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 D1EDE6B0093 for ; Wed, 26 Feb 2025 14:28:45 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 5CF091C7FD4 for ; Wed, 26 Feb 2025 19:28:45 +0000 (UTC) X-FDA: 83163083010.20.3306377 Received: from elephant.ash.relay.mailchannels.net (elephant.ash.relay.mailchannels.net [23.83.222.57]) by imf14.hostedemail.com (Postfix) with ESMTP id A849E100009 for ; Wed, 26 Feb 2025 19:28:42 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=stgolabs.net header.s=dreamhost header.b=mkc0h+Lv; spf=pass (imf14.hostedemail.com: domain of dave@stgolabs.net designates 23.83.222.57 as permitted sender) smtp.mailfrom=dave@stgolabs.net; dmarc=none; arc=pass ("mailchannels.net:s=arc-2022:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1740598123; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=pYIw9z3bS5deLOWEgf2733YFTI87p9O1CnGmqE0gF08=; b=U1b0cQqEaruITEAOitW3iLQtmRVk2qFy3PkpHc695ssNbPv3ArK/LXvzWpxde6aHYy8rnN /QJYjRYIe0Hq8YcLr3zR/hxlmghA8d+Q5tnP4l6QizyE0tPOM71L0ol5YPMR/ec4Kjkqsy BS7fRyZirmaFV67rYAmgZk0MWlxNFKQ= ARC-Authentication-Results: i=2; imf14.hostedemail.com; dkim=pass header.d=stgolabs.net header.s=dreamhost header.b=mkc0h+Lv; spf=pass (imf14.hostedemail.com: domain of dave@stgolabs.net designates 23.83.222.57 as permitted sender) smtp.mailfrom=dave@stgolabs.net; dmarc=none; arc=pass ("mailchannels.net:s=arc-2022:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1740598123; a=rsa-sha256; cv=pass; b=Y6iSlHD6JkJMhqnYgHmob1Z4zcgzqyeA2HQWpundIMC17eLtyKupznJucMiR9vsWRWzh9n dN9PObEsScwaRg1mdAma/AW62udHTCjETW0T1ESqbv2VMp2WQr0XLWFpUrVDrVALQivZr2 S0iPxi2vQbFWm98lGBg5rYDYWFCifkc= X-Sender-Id: dreamhost|x-authsender|dave@stgolabs.net Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id 0EB399054F5; Wed, 26 Feb 2025 19:28:41 +0000 (UTC) Received: from pdx1-sub0-mail-a232.dreamhost.com (100-99-192-59.trex-nlb.outbound.svc.cluster.local [100.99.192.59]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id 85BE3903CC7; Wed, 26 Feb 2025 19:28:40 +0000 (UTC) ARC-Seal: i=1; s=arc-2022; d=mailchannels.net; t=1740598120; a=rsa-sha256; cv=none; b=OKAz95KvTk5hRyDwD7osiCT/FD/FEjnfvSK3cZaf4w8vDvr4iOaCnc8iMFisKIXctETH9m 4CiUXoBk/m9tIB5C831nwrJOeHmb0Iky7c6n68rRnbEDT4T6n/atUO1HB96j+ClQ3qVklr Ch0pMX0RFFRe8XceTwPo2mKcFXcVnBKK4AFBB49oNWIold7L3tyswycOLhEZCl18gkZhWk xJRU//KP/8EjznmlDjm2JkYNawmf8V+LqfHLpcD8hwwzb3hda5lqtqs2r5FwHzbEXazgAW hKyK7QJKqzeyxa33WiUTjAJ8wZrgBUPvAT+FtKOf7hsi4io2qf3cMI3UmjiaWg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=mailchannels.net; s=arc-2022; t=1740598120; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references:dkim-signature; bh=pYIw9z3bS5deLOWEgf2733YFTI87p9O1CnGmqE0gF08=; b=UWQRn6xsASkGBMAtFOr/ULkhbwi1IpSOwjhH86ZbdrwhTE61imWUpb2iyKM9npq5EcUGAn LyRJRWqDN9hXK6RLhmIBeKl2/wkzKSMHKYvTc/iocQMbcgIeU+Dyc9PmUf0OVRmWu0AQPS pkiPLPVxCtjbZ/vLa0OyGsgVKPZbDB+bmK2Ee1D45ulnC4K3RO5R8qH0BrNp6O/G7Sjl6+ 3kVr23g6aq9wyCtCae3ulKKolU8Jd9nWUjYmF8oA4DMHbbcMtLPRl314sQLOpzTO71MgRe Zd5C3g2h74czoGSuUEeToI/aPDOc4RU26HeKflI+IisA1CYPfr9qtWLSR9JNlQ== ARC-Authentication-Results: i=1; rspamd-6d7cc6b78d-jpb69; auth=pass smtp.auth=dreamhost smtp.mailfrom=dave@stgolabs.net X-Sender-Id: dreamhost|x-authsender|dave@stgolabs.net X-MC-Relay: Neutral X-MailChannels-SenderId: dreamhost|x-authsender|dave@stgolabs.net X-MailChannels-Auth-Id: dreamhost X-Shrill-Squirrel: 7e800a0258e359d8_1740598120877_3242746971 X-MC-Loop-Signature: 1740598120877:4221620723 X-MC-Ingress-Time: 1740598120877 Received: from pdx1-sub0-mail-a232.dreamhost.com (pop.dreamhost.com [64.90.62.162]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384) by 100.99.192.59 (trex/7.0.2); Wed, 26 Feb 2025 19:28:40 +0000 Received: from offworld (ip72-199-50-187.sd.sd.cox.net [72.199.50.187]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dave@stgolabs.net) by pdx1-sub0-mail-a232.dreamhost.com (Postfix) with ESMTPSA id 4Z34Jl41B8zLF; Wed, 26 Feb 2025 11:28:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stgolabs.net; s=dreamhost; t=1740598120; bh=pYIw9z3bS5deLOWEgf2733YFTI87p9O1CnGmqE0gF08=; h=Date:From:To:Cc:Subject:Content-Type; b=mkc0h+Lv2m2i8Hp/ny7cTPnrR/Rj06rgBp19qbgM+HJkUxv4+L7sNLswOk1B+LvPW Hr5aiWVaS+rtM/rLs3zK92JGFKVRBVUm41EGuEVNzWT0itjZGxW70SJfEkWQr+iZgY kdKj1/z1jYwQRFhpy2Wvxj8hl//mgctMgkBfk4rB+3hmNF6Hg6669l0tzAx7Hh/QiJ 61hmzUNp0hVBL7EOmEF7ylfynogImtwg9gI+QwADgUCmjeiiR4oYn8saabBknSlfZq ikU24o3LalQBplB+pTzYYrCmPApZqou/d3a0GGanJ74pHq5BRVaC9ArYVNYeYOW+aT sr28ct+tivzmw== Date: Wed, 26 Feb 2025 11:28:35 -0800 From: Davidlohr Bueso To: Alexei Starovoitov Cc: Vlastimil Babka , Suren Baghdasaryan , "Liam R. Howlett" , Christoph Lameter , David Rientjes , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Uladzislau Rezki , linux-mm , LKML , rcu@vger.kernel.org, maple-tree@lists.infradead.org, Sebastian Andrzej Siewior , Alexei Starovoitov Subject: Re: [PATCH RFC v2 03/10] locking/local_lock: Introduce localtry_lock_t Message-ID: <20250226192835.bmehafm2rjcbq42z@offworld> Mail-Followup-To: Alexei Starovoitov , Vlastimil Babka , Suren Baghdasaryan , "Liam R. Howlett" , Christoph Lameter , David Rientjes , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Uladzislau Rezki , linux-mm , LKML , rcu@vger.kernel.org, maple-tree@lists.infradead.org, Sebastian Andrzej Siewior , Alexei Starovoitov References: <20250214-slub-percpu-caches-v2-0-88592ee0966a@suse.cz> <20250214-slub-percpu-caches-v2-3-88592ee0966a@suse.cz> <20250226170053.lxpreaegz5tysef7@offworld> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20220429 X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: A849E100009 X-Stat-Signature: y9tkp1xuw3y1sucqp6r688ekekb8tr1f X-HE-Tag: 1740598122-312279 X-HE-Meta: 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 6FXEKhTf 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000036, 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 Wed, 26 Feb 2025, Alexei Starovoitov wrote: >On Wed, Feb 26, 2025 at 9:01???AM Davidlohr Bueso wrote: >> >> On Fri, 14 Feb 2025, Vlastimil Babka wrote: >> >> >From: Sebastian Andrzej Siewior >> > >> >In !PREEMPT_RT local_lock_irqsave() disables interrupts to protect >> >critical section, but it doesn't prevent NMI, so the fully reentrant >> >code cannot use local_lock_irqsave() for exclusive access. >> > >> >Introduce localtry_lock_t and localtry_lock_irqsave() that >> >disables interrupts and sets acquired=1, so localtry_lock_irqsave() >> >from NMI attempting to acquire the same lock will return false. >> > >> >In PREEMPT_RT local_lock_irqsave() maps to preemptible spin_lock(). >> >Map localtry_lock_irqsave() to preemptible spin_trylock(). >> >When in hard IRQ or NMI return false right away, since >> >spin_trylock() is not safe due to PI issues. >> > >> >Note there is no need to use local_inc for acquired variable, >> >since it's a percpu variable with strict nesting scopes. >> > >> >> LGTM. >> >> Acked-by: Davidlohr Bueso > >Thanks for the review. >Do you mind if I apply your ack to the latest version of this patch? >https://lore.kernel.org/bpf/20250222024427.30294-2-alexei.starovoitov@gmail.com/ Yes, that is fine. Thanks, Davidlohr