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 A4F83C02198 for ; Tue, 18 Feb 2025 15:17:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E4CD8280141; Tue, 18 Feb 2025 10:17:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DFCDF28013C; Tue, 18 Feb 2025 10:17:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C9DD4280141; Tue, 18 Feb 2025 10:17:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id ACE5928013C for ; Tue, 18 Feb 2025 10:17:36 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 2E4A1141D44 for ; Tue, 18 Feb 2025 15:17:36 +0000 (UTC) X-FDA: 83133419712.02.3261BE1 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by imf29.hostedemail.com (Postfix) with ESMTP id DC9EC120019 for ; Tue, 18 Feb 2025 15:17:31 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=tR845+np; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=r3SEbcEt; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=tR845+np; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=r3SEbcEt; spf=pass (imf29.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 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=1739891852; 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=GSfP9OfO4UmQP2itE5XGZaCFubr9vckyPt4xBYaJ5sw=; b=oiwaZcSZbI6dfjsRJib3n56YurH4NUmaDxgxUskyTOqIHNExC/DWYgKkCoMzeqiICW2Vgc WRYw13caKLG718WtWU8bHqg+10fd6nSDDuzku9xP3he9Ctxb8Thr6wj0EpGliUWTYNMNhp ivQrfc9D00e8f2iznQNkDYDKZ1kgpbw= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=tR845+np; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=r3SEbcEt; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=tR845+np; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=r3SEbcEt; spf=pass (imf29.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739891852; a=rsa-sha256; cv=none; b=pGQsKzZ0UPdgg1tup7b5qmbmQvcxxlzmLleLA2RaGJLXvNDslIluWstYE+Kmp9hhYwQJcP YVJVSVBW7mjCX3oF7nwdaAX465WKusHIkvrIHiqW7ydmD4OHsHZKKzCsVFe1oHgFUVddVG PWi34SPgxb9UXLFsc2yQ/PfOMGxtt5A= Received: from imap1.dmz-prg2.suse.org (unknown [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-out2.suse.de (Postfix) with ESMTPS id B87791F396; Tue, 18 Feb 2025 15:17:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1739891849; 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=GSfP9OfO4UmQP2itE5XGZaCFubr9vckyPt4xBYaJ5sw=; b=tR845+np0F2WRzTieK8oe+Xa7gSC+/l1ATEtVsE080+o0gITFOBIdFZll5x1YsHGwUaXi6 vWrgn+YkUuoGkmCMfclQSnb4UUxztJeGNnlQUx+H1StFNlfR/2xBjelTuoetWhk29OwtKG gZiCt6ODUg5jwKO2K1Iw2gMIDHSzOe0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1739891849; 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=GSfP9OfO4UmQP2itE5XGZaCFubr9vckyPt4xBYaJ5sw=; b=r3SEbcEtI8hdhXaQ5R9/NpOttVahvQr0vj+A4l6fIpGIShSHsBXfYNgFQw2OcstRQn2hGX r0WnZQanpRHuUZAA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1739891849; 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=GSfP9OfO4UmQP2itE5XGZaCFubr9vckyPt4xBYaJ5sw=; b=tR845+np0F2WRzTieK8oe+Xa7gSC+/l1ATEtVsE080+o0gITFOBIdFZll5x1YsHGwUaXi6 vWrgn+YkUuoGkmCMfclQSnb4UUxztJeGNnlQUx+H1StFNlfR/2xBjelTuoetWhk29OwtKG gZiCt6ODUg5jwKO2K1Iw2gMIDHSzOe0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1739891849; 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=GSfP9OfO4UmQP2itE5XGZaCFubr9vckyPt4xBYaJ5sw=; b=r3SEbcEtI8hdhXaQ5R9/NpOttVahvQr0vj+A4l6fIpGIShSHsBXfYNgFQw2OcstRQn2hGX r0WnZQanpRHuUZAA== 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 8608213A1D; Tue, 18 Feb 2025 15:17:29 +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 4NhfIImktGcncwAAD6G6ig (envelope-from ); Tue, 18 Feb 2025 15:17:29 +0000 Message-ID: <8307f3b1-0e6b-48cf-8553-6e7568e08ed4@suse.cz> Date: Tue, 18 Feb 2025 16:17:29 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v8 3/6] locking/local_lock: Introduce localtry_lock_t Content-Language: en-US To: Alexei Starovoitov , bpf@vger.kernel.org Cc: andrii@kernel.org, memxor@gmail.com, akpm@linux-foundation.org, peterz@infradead.org, bigeasy@linutronix.de, rostedt@goodmis.org, houtao1@huawei.com, hannes@cmpxchg.org, shakeel.butt@linux.dev, mhocko@suse.com, willy@infradead.org, tglx@linutronix.de, jannh@google.com, tj@kernel.org, linux-mm@kvack.org, kernel-team@fb.com References: <20250213033556.9534-1-alexei.starovoitov@gmail.com> <20250213033556.9534-4-alexei.starovoitov@gmail.com> 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+fMgqZkBQJkBREIBQkRadznAAoJECJPp+fMgqZkNxIQ ALZRqwdUGzqL2aeSavbum/VF/+td+nZfuH0xeWiO2w8mG0+nPd5j9ujYeHcUP1edE7uQrjOC Gs9sm8+W1xYnbClMJTsXiAV88D2btFUdU1mCXURAL9wWZ8Jsmz5ZH2V6AUszvNezsS/VIT87 AmTtj31TLDGwdxaZTSYLwAOOOtyqafOEq+gJB30RxTRE3h3G1zpO7OM9K6ysLdAlwAGYWgJJ V4JqGsQ/lyEtxxFpUCjb5Pztp7cQxhlkil0oBYHkudiG8j1U3DG8iC6rnB4yJaLphKx57NuQ PIY0Bccg+r9gIQ4XeSK2PQhdXdy3UWBr913ZQ9AI2usid3s5vabo4iBvpJNFLgUmxFnr73SJ KsRh/2OBsg1XXF/wRQGBO9vRuJUAbnaIVcmGOUogdBVS9Sun/Sy4GNA++KtFZK95U7J417/J Hub2xV6Ehc7UGW6fIvIQmzJ3zaTEfuriU1P8ayfddrAgZb25JnOW7L1zdYL8rXiezOyYZ8Fm ZyXjzWdO0RpxcUEp6GsJr11Bc4F3aae9OZtwtLL/jxc7y6pUugB00PodgnQ6CMcfR/HjXlae h2VS3zl9+tQWHu6s1R58t5BuMS2FNA58wU/IazImc/ZQA+slDBfhRDGYlExjg19UXWe/gMcl De3P1kxYPgZdGE2eZpRLIbt+rYnqQKy8UxlszsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZAUSmwUJDK5EZgAKCRAiT6fnzIKmZOJGEACOKABgo9wJXsbWhGWYO7mD 8R8mUyJHqbvaz+yTLnvRwfe/VwafFfDMx5GYVYzMY9TWpA8psFTKTUIIQmx2scYsRBUwm5VI EurRWKqENcDRjyo+ol59j0FViYysjQQeobXBDDE31t5SBg++veI6tXfpco/UiKEsDswL1WAr tEAZaruo7254TyH+gydURl2wJuzo/aZ7Y7PpqaODbYv727Dvm5eX64HCyyAH0s6sOCyGF5/p eIhrOn24oBf67KtdAN3H9JoFNUVTYJc1VJU3R1JtVdgwEdr+NEciEfYl0O19VpLE/PZxP4wX PWnhf5WjdoNI1Xec+RcJ5p/pSel0jnvBX8L2cmniYnmI883NhtGZsEWj++wyKiS4NranDFlA HdDM3b4lUth1pTtABKQ1YuTvehj7EfoWD3bv9kuGZGPrAeFNiHPdOT7DaXKeHpW9homgtBxj 8aX/UkSvEGJKUEbFL9cVa5tzyialGkSiZJNkWgeHe+jEcfRT6pJZOJidSCdzvJpbdJmm+eED w9XOLH1IIWh7RURU7G1iOfEfmImFeC3cbbS73LQEFGe1urxvIH5K/7vX+FkNcr9ujwWuPE9b 1C2o4i/yZPLXIVy387EjA6GZMqvQUFuSTs/GeBcv0NjIQi8867H3uLjz+mQy63fAitsDwLmR EP+ylKVEKb0Q2A== In-Reply-To: <20250213033556.9534-4-alexei.starovoitov@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: DC9EC120019 X-Stat-Signature: 7b5z7hc3phj7dxam6gty1hyhqeoarcfq X-Rspamd-Server: rspam03 X-HE-Tag: 1739891851-790332 X-HE-Meta: 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 x7XgB/DY k2O3O/s7sfdWukY9JQn3xkXWg/RyTVGq6KZ6r/VBpN0hgCPGeSidwTXomiq83yloXMEZWPjMqPN0pYeNWc1JssNc4VunWDihRrQ8/AfzwMirpV8vs6PYOvpW088wvjwKG7wYK2qa0klJg1s6dRdK2edf3p6l7rRNLqCc/ci/CaGNZq2S1J1OpULUcrdjTGYe9sgbWpg+aq9dLFc2aj4awsQ09Jcm1tJh3n9pUnjZ+tIUXjNrDmvUiSIsFvYu7GrFn9W/Mlys4TPjSCc6OhTh50JTsC86PI/7jf8M6Bey5a8WwKIJ8AGmy7uQV28DN1s6X5C81MYYqQhhMfcN7MFH8scO4/ExcCHFdwytzadkBu9pO7gbDDVSgneHxxWgbWdznqsLrnXX99dEbso0Nq/7i7wOYBSIt+Vm4fLfkPiFDpEgnt8J23e5zS9Xe138SOcqOdLAYFhxRU0JsiDpIyw+zemSlpA== 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 2/13/25 04:35, Alexei Starovoitov 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. > > Signed-off-by: Sebastian Andrzej Siewior > Signed-off-by: Alexei Starovoitov I'm not the maintainer of this area, but with the fixes/addition I proposed, and having use for this lock variant myself, I think it's fair to add, fwiw: Acked-by: Vlastimil Babka Thanks.