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 45A97C77B72 for ; Wed, 12 Apr 2023 11:34:25 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4PxLG74Xthz3fFV for ; Wed, 12 Apr 2023 21:34:23 +1000 (AEST) 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=OeJpnwPQ; 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=peterz@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=OeJpnwPQ; 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 4PxLF41gtgz3c2j for ; Wed, 12 Apr 2023 21:33:27 +1000 (AEST) 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=ptb2avmE0b7kYpkD6HQ5sKXtmJgMCEPhKl497g20A1Q=; b=OeJpnwPQVQrSrkQnsPYnkVz6Xn MQHlpDq4OctaeZMIotctQRvuZFYgTUiewZ7yhKiM52JM3lAIDo3z9I7QtTxis1qzyh+z8drUYv/WV bfbaBd2P8XywYXeiBMI5PritExaKlrWXJd7/wY7wiQAHiZblhmhYLud/MzynJ+MYFFW0+5xyzQc6I virTasGQ1pP9Bw2IUpE4ZnHiiBOZdruaGxw9KZH5HnVc+61Syh0q79vu8y30TAFx7q+e26Z3cuEp/ bsMrHDSoGfQD+fNsEp4WZY7Lu2KON5AN0m6qsqM2FWXzkMBO2BMwFxx8Is50hsXaD3MySaIdcQUTV LkPO9Wwg==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1pmYiM-006owg-IO; Wed, 12 Apr 2023 11:32:38 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (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) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D3F083002A6; Wed, 12 Apr 2023 13:32:31 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A7D4525E5A38B; Wed, 12 Apr 2023 13:32:31 +0200 (CEST) Date: Wed, 12 Apr 2023 13:32:31 +0200 From: Peter Zijlstra To: Uros Bizjak Subject: Re: [PATCH v2 3/5] locking/arch: Wire up local_try_cmpxchg Message-ID: <20230412113231.GA628377@hirez.programming.kicks-ass.net> References: <20230405141710.3551-1-ubizjak@gmail.com> <20230405141710.3551-4-ubizjak@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230405141710.3551-4-ubizjak@gmail.com> 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: x86@kernel.org, Dave Hansen , Jiaxun Yang , linux-kernel@vger.kernel.org, "H. Peter Anvin" , WANG Xuerui , linux-arch@vger.kernel.org, Jun Yi , Huacai Chen , Ingo Molnar , Matt Turner , Richard Henderson , Nicholas Piggin , Ivan Kokshaysky , loongarch@lists.linux.dev, Thomas Gleixner , Thomas Bogendoerfer , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-alpha@vger.kernel.org, Borislav Petkov , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Apr 05, 2023 at 04:17:08PM +0200, Uros Bizjak wrote: > diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h > index bc4bd19b7fc2..45492fb5bf22 100644 > --- a/arch/powerpc/include/asm/local.h > +++ b/arch/powerpc/include/asm/local.h > @@ -90,6 +90,17 @@ static __inline__ long local_cmpxchg(local_t *l, long o, long n) > return t; > } > > +static __inline__ bool local_try_cmpxchg(local_t *l, long *po, long n) > +{ > + long o = *po, r; > + > + r = local_cmpxchg(l, o, n); > + if (unlikely(r != o)) > + *po = r; > + > + return likely(r == o); > +} > + Why is the ppc one different from the rest? Why can't it use the try_cmpxchg_local() fallback and needs to have it open-coded?