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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 1DB37C54EBE for ; Mon, 16 Jan 2023 15:11:14 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Nwb811rCSz3cDT for ; Tue, 17 Jan 2023 02:11:13 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=E7mc3QbK; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2001:8b0:10b:1236::1; helo=casper.infradead.org; envelope-from=willy@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=E7mc3QbK; dkim-atps=neutral Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Nwb6x1K5Wz30gk for ; Tue, 17 Jan 2023 02:10:16 +1100 (AEDT) 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=JYw4vYNo6I8ONL1oEHQpMq0Clr6CFL2bXHpSXpJOtI0=; b=E7mc3QbKC7DPlTHSAjTqru6OUZ Kcs0+09JF2aMv6SI5wQOt5rSq0BM8ct5mlPnirn/4I6QRcjS0hfJBo+x3Ny3hfq1FoEia6+CcSw4d Ln3RqowsC/MpEce8Kaq588urT3GLTAs6FzQ7UQfh7+V2rdRQYSJ1zK5+bWn6CaJPOBY5p4U4BOzV6 OtOBMBvR44bGeLU2GMbt0MEeofc23vH+kjnBDDkuASHVjacOFQrEzK+xeBE2UyppGDUIV5I1CfgzX a2UFVC3h1+gI1FCNORS0EaQAVLf46ZAG4YoN1e0EblBtA+2QEp5Fu/0Q/Wk4pK4A2ckvbUgUn9jWZ B2kGePaw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pHR7V-008puo-Vx; Mon, 16 Jan 2023 15:09:58 +0000 Date: Mon, 16 Jan 2023 15:09:57 +0000 From: Matthew Wilcox To: David Howells Subject: Re: Memory transaction instructions Message-ID: References: <1966767.1673878095@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1966767.1673878095@warthog.procyon.org.uk> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch , Mateusz Guzik , Catalin Marinas , linuxppc-dev , Nicholas Piggin , Linus Torvalds , tony.luck@intel.com, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, Jan Glauber , Will Deacon , Linux ARM Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Jan 16, 2023 at 02:08:15PM +0000, David Howells wrote: > Hi Linus, > > I'm not sure how relevant it is to the topic, but I seem to remember you > having a go at implementing spinlocks with x86_64 memory transaction > instructions a while back. Do you have any thoughts on whether these > instructions are ever likely to become something we can use? Ever is a long time, but not while they're still buggy: https://en.wikipedia.org/wiki/Transactional_Synchronization_Extensions and not while they're not actually available on a vast majority of x86 hardware. ie AMD needs to implement them, make them available as standard, forcing Intel to enable them globally instead of restricting them to those who pay the $2.50/month subscription fee.