From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 984EF223316; Thu, 26 Jun 2025 10:16:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750933013; cv=none; b=g11/a9cDX8AF4s9NpgDE3MS7Y3W+raDJ6GKqAePbHPhU6my03DuZtKIQHlmEd0+6BnZpsbEjLEquq8/MK/pW6UQKvFqJ1iDBOvaVyrn69FAKRsH8y6aQTpD5DLppRYfZFACOOdkBLv0XV1HsBktVOVvmpjTeeVBHU/aww8yEocI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750933013; c=relaxed/simple; bh=GBSozoWWKRKZJrCGFCdZ43CXvJAlMWvl9OaRxXSMWT8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RLzKK607dnsbTD/VFd3Wc2O35Nhc4tCw9mQJPoN0uf1jVUod7toqnSbZnXbnLgJ2dM5O4wYL8Nn83vV+kIWhUOkv9z+DUPOZ0q6pTZlVzwpcDqFzRYDgyW7b32CdeVSxMWDigDO8RkjO5yg9Oh2u6t17oTgFlf5eMNF9iiBrqpU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=hA6stHRW; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="hA6stHRW" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=GBSozoWWKRKZJrCGFCdZ43CXvJAlMWvl9OaRxXSMWT8=; b=hA6stHRWbGabrP0nAwAWoTMcZF eJOUeXz1a9oYFVsu9p03reHpmUahcEb40hbN/qsZv+k52oDDha4kjJdu61MiUH818eOSH8OHc7/5/ cWxShLIQFXB/Z8pPjuztsw4GaEgx0agBB+WieYS/W6ADB8yP40kuOLXAMcfKuy2sA4gcTbyNIEIri KQZPZ/NLpNDKi73asapwljVb7QC+WdEFzA6N/Uat2EoEGVt/64eGG35YJxlfa/oLu98AKMEi+Je1G VXh0BBLVJEcW8YM1i05rbuQshuh/esiB/zuKCvCgkBg20bZZp66+ffAp0ghWTUtlk1quPilRKcIjh mvTtxtUA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUjez-0000000BG9H-1fW8; Thu, 26 Jun 2025 10:16:49 +0000 Date: Thu, 26 Jun 2025 03:16:49 -0700 From: Christoph Hellwig To: Boqun Feng Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, rcu@vger.kernel.org, lkmm@lists.linux.dev, Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Breno Leitao , aeh@meta.com, netdev@vger.kernel.org, edumazet@google.com, jhs@mojatatu.com, kernel-team@meta.com, Erik Lundgren Subject: Re: [PATCH 0/8] Introduce simple hazard pointers for lockdep Message-ID: References: <20250625031101.12555-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: netdev@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Jun 25, 2025 at 07:08:57AM -0700, Boqun Feng wrote: > Sure, I will put one for the future version, here is the gist: Thanks a lot! > The updater's wait can finish immediately if no one is accessing 'a', in > other words it doesn't need to wait for reader 2. So basically it is the RCU concept, but limited to protecting exactly one pointer update per critical section with no ability for the read to e.g. acquire a refcount on the objected pointed to by that pointer?