From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 956D94683; Sat, 15 Jun 2024 01:43:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718415790; cv=none; b=hyTX2bs2b2s30EIKJQ5nivWGUwQM3lJzBqeSb+L0o1GhXCXQZbob2FJMRrNHWMZi6gwj7UISuocwva1ynsGRkO+i2K53zoCMdj489uROOC5ceXEIKxeHu37XpGnuJtqGKz1WzjDSNl7N6z/PhGpLtrxgylWJNt3DN5AYsYH94Vo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718415790; c=relaxed/simple; bh=8Zinys3yZee54O7Jb/EuJVXbITn3qoh6d5kKIUE3bw8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eo63CUpaqKlLzdiuoLV8qrctK5SYT+HMCHHPVCQzSqPwagxRC2S5mclt8QPE2UT7DWuJpVCTHmcZMz5mSNO7fLrZ/qF3hxuU2eOrXrDdT+zeGzZ/G+jO+dgFZmNSepf1j4DaKN5mNFoKF14xjSc/t4A/j/IYjqnO5BicX6eEHAk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=BG9EAzL4; arc=none smtp.client-ip=90.155.50.34 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=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="BG9EAzL4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=JLTvDV1lNU9XfbpR4Y9KnupD1/9SE9kaeQL+4/ORc5U=; b=BG9EAzL4aNe5yXJ8hUlpJr41e2 JLmkcwHOSWQpGdf0kCw978PqipCPe5wQqcQYPoTGj5qdH2BjLO25E0I5Xbmuxh7ras6sH5320jBTm 3ccSVJvWPlOy+8vvwHxDkulKaq+0SdGAZWJst1q9monnCJS8aZ28oGoMDGTo9Tl+bgTbuHmTvuO2P TI+IYMfifnbJQlH8/a2+n/YaYq26qvQgQ17tUfDlS6sfPw6xtPsBDwmIN9QHzpgcZspjz1TcJpyVh OniE5Iu5C4JJkjb2MKxFjs0W+59zRyHx0N5qBEUaRjm0PVow6X91bGKmnKok4GdGkxX44dC78EvW0 vYM65rEw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1sIIRV-0000000HUXc-1Tx0; Sat, 15 Jun 2024 01:43:00 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id E4982300886; Sat, 15 Jun 2024 03:42:56 +0200 (CEST) Date: Sat, 15 Jun 2024 03:42:56 +0200 From: Peter Zijlstra To: Vincent Guittot Cc: K Prateek Nayak , linux-kernel@vger.kernel.org, "Gautham R. Shenoy" , Richard Henderson , Ivan Kokshaysky , Matt Turner , Russell King , Guo Ren , Michal Simek , Dinh Nguyen , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Naveen N. Rao" , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "David S. Miller" , Andreas Larsson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Rafael J. Wysocki" , Daniel Lezcano , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Andrew Donnellan , Benjamin Gray , Frederic Weisbecker , Xin Li , Kees Cook , Rick Edgecombe , Tony Battersby , Bjorn Helgaas , Brian Gerst , Leonardo Bras , Imran Khan , "Paul E. McKenney" , Rik van Riel , Tim Chen , David Vernet , Julia Lawall , linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-pm@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v2 00/14] Introducing TIF_NOTIFY_IPI flag Message-ID: <20240615014256.GQ8774@noisy.programming.kicks-ass.net> References: <20240613181613.4329-1-kprateek.nayak@amd.com> <20240614092801.GL8774@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@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: On Fri, Jun 14, 2024 at 12:48:37PM +0200, Vincent Guittot wrote: > The main problem is that need_resched becomes somewhat meaningless > because it doesn't only mean "I need to resched a task" and we have > to add more tests around even for those not using polling The converse problem is that you're adding a bunch of atomic ops that might be avoided. It might now need to set both the RESCHED and IPI flags -- and clear them again.