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 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.lore.kernel.org (Postfix) with ESMTPS id CE178C54EFC for ; Tue, 28 Jul 2026 11:08:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XUdocc9AyfaWpOM5SNPJip/RwRNo5MSCyklyHVO9Wws=; b=nEpM5DQSPxBw145dDqgBIVVX9Z B80kSQGR8NZwgC/vtqjCK2bRxd4vvx+SQbfphxBh5OV2RvzAij3+kqXsVU+3IYzOK/V7XSgOVxD3X rIXyYT2D1z78xoDynUjd+pTAQDJaFus1igOj7wuiefA9blduu+Tgv/tT0csVhO2uEyA70urgQX7Uu JfmahdUEPYWzFoQM7/6LfDU7yDtJLj5f5eZltTwHBtRjWWRdrEG7wJ7e2zx75C/xX9i7h3UtADt+Y RM7KiHLMGnqdtbcaGZrAN7ar6PwCSUx/Nhp/xvUNaaxP0AuSnqG5kg+m4IU/uwbWuYJuyUCLoWHng 8MOXSTyA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1woffS-0000000529Z-42cL; Tue, 28 Jul 2026 11:08:14 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1woffR-0000000529M-2XAW; Tue, 28 Jul 2026 11:08:13 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=XUdocc9AyfaWpOM5SNPJip/RwRNo5MSCyklyHVO9Wws=; b=F4iPhNzOmo8NpbJb+tV6CswPGi +YCKtt8bsid6mcaEYcbDf3iYC8DCtCRsMy/bsVClYGCieP2r8DU303Iv4guwsi7UYqR03nOeEDkSK 56qpqtPT/VLc8PvXtZ5h/g7q9erG4AKjqUkG+4eIl0qMv/j/Xb932EoEnjm4KYzrDd5Fk7iwfl41u grFxNPvv2ez60OT3dtPnXylCD1+t/nHHTdYxSmbEUVfTcxHTiv7zkgE7fT/yZm8u8OznQD9ribqUi G+fI3woBoHEUDLnKzKsPe7ptdNYj4VnHFzS9cC7Ixype8if2pU52BCJYozxNfjNECkFbGIqBlqMED OZuDKqQg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.2 #2 (Red Hat Linux)) id 1woffL-00000004ryR-2Oyk; Tue, 28 Jul 2026 11:08:07 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 1DC6330093A; Tue, 28 Jul 2026 13:08:06 +0200 (CEST) Date: Tue, 28 Jul 2026 13:08:06 +0200 From: Peter Zijlstra To: K Prateek Nayak Cc: Arnd Bergmann , Thomas Gleixner , Ingo Molnar , Sebastian Andrzej Siewior , Charlie Jenkins , Borislav Petkov , Dave Hansen , x86@kernel.org, Catalin Marinas , Will Deacon , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Darren Hart , Davidlohr Bueso , =?iso-8859-1?Q?Andr=E9?= Almeida , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, "H. Peter Anvin" , Sean Christopherson , Thomas Huth , Jisheng Zhang , Ben Dooks , Samuel Holland , Radim =?utf-8?B?S3LEjW3DocWZ?= , Guo Ren , Christian Borntraeger , Sven Schnelle Subject: Re: [PATCH v6 8/8] futex: Use runtime constants for __futex_hash() hot path Message-ID: <20260728110806.GJ49951@noisy.programming.kicks-ass.net> References: <20260728052540.4728-1-kprateek.nayak@amd.com> <20260728052540.4728-9-kprateek.nayak@amd.com> <20260728104653.GH49951@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260728104653.GH49951@noisy.programming.kicks-ass.net> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jul 28, 2026 at 12:46:53PM +0200, Peter Zijlstra wrote: > On Tue, Jul 28, 2026 at 05:25:40AM +0000, K Prateek Nayak wrote: > > From: Peter Zijlstra > > > > Runtime constify the read-only after init data __futex_shift(shift_32), > > __futex_mask(mask_32), and __futex_queues(ptr) used in __futex_hash() > > hot path to avoid referencing global variable. > > > > This also allows __futex_queues to be allocated dynamically to > > "nr_node_ids" slots instead of reserving config dependent MAX_NUMNODES > > (1 << CONFIG_NODES_SHIFT) worth of slots upfront. > > > > Runtime constants are initialized before their first access and > > runtime_const_init() provides necessary barrier to ensure subsequent > > accesses are not reordered against their initialization. > > > > No functional changes intended. > > > > [ prateek: Dynamically allocate __futex_queues, mark the global data > > __ro_after_init since they are constified after futex_init(). ] > > > > Link: https://patch.msgid.link/20260227161841.GH606826@noisy.programming.kicks-ass.net > > Reported-by: Sebastian Andrzej Siewior # MAX_NUMNODES bloat > > Signed-off-by: Peter Zijlstra > > Reviewed-by: Charlie Jenkins > > Tested-by: Charlie Jenkins > > Signed-off-by: K Prateek Nayak > > --- > > changelog v5..v6: > > > > o Picked up tags from Charlie. (Thanks a ton!) > > > > o Picked up Peter's S-o-b from his tree. > > Right, so I also munged the Changelog in my tree to include those > benchmark results. I failed to actually push out those patches before > disappearing on holidays, but I recon I should refresh them patches and > re-munge the changelog? With a bit of luck I didn't wreck things and this new version should now be available in queue/locking/core.