From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=5.75.144.95 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793731797; b=p+R98Mg53og0u35t0sbpdPnSgdMfQa96Tz08FF70LAMv1cKPnoYX3unEfofiDUl8bM6h RlMKrRgVx9dhaCBZzCoOx6H/ZceoVzG6zFxEvf3Ovpv8MIvg4d8yOVBb1wZM0W/q/FbmZ 9XtS1zWL4Y/QVpLuYK3LjUAGHD993oCjT5wKu1KOKJ/lXM7O2TyyVzKxgPWV/afHyHiVv kfgAwgQcCqBBPnfDXuZzXX8/VsgwNKHv6v5HG4zI8MLWfhqeyeFd/gBtkyZH934exhC73 uUNjDXiKPdkEyuEpTPQ04DxmYElEk8wLYk8JWtt+cnw/yYmLQVJYGU8NiCEeyi9x5Pw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793731797; h=DMARC-Filter:DKIM-Signature:DKIM-Signature:Date:From:To:CC:Subject: In-Reply-To:References:Message-ID:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=qmufM6raPP/JE8IC4efMBvY+lfo59L1JtLhgHRWcfbw=; b=YnqcH0/i0KVwJ7CiduItTltwL2K1+/+lMYPEMFcAUxv8MSvsZe5iKAPxIw8MCzR+fNXv z2UQycWG91M9d8amDNHD+EWe4qdJ6OmwAXK8dzFBGEAA5K6ju3pKvU/idgLWMFfbcn7/o 3usCbsAmRc2goWqKf1n8jT54mAjwd9bAgfItSoNNLqwv7LT3QGY4e0jJ4+I2moJtGCqSf jovuSOYrhUrjJ19tZMNrglOmjinemZUzp7RoQy7SCaGt4AZe5LLt91Dvb3JBR1z5O4sWP KJFewhVdZ9/rBQ5pZ/OrdMSBcMspABb4ney1IvFi3B5sstglqT+ij6VgdLUtMol5Sig== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=mainlining.org; spf=pass smtp.mailfrom=mainlining.org; dkim=pass header.d=mainlining.org header.i=@mainlining.org header.a=rsa-sha256 header.s=202507r header.b=qA0qT1vF; dkim=pass header.d=mainlining.org header.i=@mainlining.org header.a=ed25519-sha256 header.s=202507e header.b=uCAaNScI; arc=none smtp.remote-ip=5.75.144.95 Received: from mail.mainlining.org (mail.mainlining.org [5.75.144.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E2870606A31B for ; Tue, 3 Nov 2026 18:49:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E2870606A31B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mainlining.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=mainlining.org header.i=@mainlining.org header.a=rsa-sha256 header.s=202507r header.b=qA0qT1vF; dkim=pass header.d=mainlining.org header.i=@mainlining.org header.a=ed25519-sha256 header.s=202507e header.b=uCAaNScI DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Subject:To:From:Date; t=1793731777; bh=qmufM6raPP/JE8IC4efMBvY +lfo59L1JtLhgHRWcfbw=; b=qA0qT1vFUlfZf/YOCMyEkddy9ky7IotHriBxqGBRZQKEP1+KGZ qRQFA61k9s/M1Zqc0tQzOvF1GttpIzgYs6N15Bs84B+QSkMydvEE4OW1MhLPsJ2lZ1VdloJ/OZ/ 0l7M0whulqhZHRhCohl48PuSd8Wc2DxgvN3wCsX574MzlHnl+FdPI8OfBQ9A32DDeUrZdqUU2rV Vg6mwJyLJ0T/KaF8SbzHVjLDimXFjuXZOGzEZNaJaHHviNrqzR8yixKgVcc485DajShqEBODqCG eWR88KBEmIDrDuwwaozFdRBoMHB7t85w3C8YyNZJ7vMacvB8zX2E0+ErupLjI+kJeOA==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Subject:To:From:Date; t=1793731777; bh=qmufM6raPP/JE8IC4efMBvY +lfo59L1JtLhgHRWcfbw=; b=uCAaNScIJcrmC96mfiWOfQgZjvRYhQi7ALsdRMmBZJDbghnr0u C1UMye/aXKX5Csuira+RifYL0dp4Xcm4ehCA==; Date: Tue, 03 Nov 2026 18:49:35 +0000 From: Bradley Morgan To: paulmck@kernel.org, "Paul E. McKenney" , Jan Engelhardt CC: David Laight , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, Arnd Bergmann Subject: Re: [GIT PULL] Add two-byte cmpxchg emulation function for v7.4 In-Reply-To: References: <4p5316or-75o2-s068-74s3-6q5011o75672@vanv.qr> <6f24126a-7f84-40f8-a297-095b470beb8b@paulmck-laptop> <20261102163448.3956dde3@pumpkin> Message-ID: X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit On 3 November 2026 18:19:23 GMT, "Paul E. McKenney" wrote: >On Tue, Nov 03, 2026 at 03:03:47AM +0100, Jan Engelhardt wrote: >> >> On Monday 2026-11-02 17:34, David Laight wrote: >> >> >> >> I can get gcc-17.0.0-20261102 with no further command line options >> >> to turn `atomic_compare_exchange_strong`+uint16 into some object code >> >> that does not contain a call to libatomic, for sh2, sh3, sh4. Haven't >> >> tried xtensa or the others. >> >> Thus, is the patch really needed? >> > >> >Won't that need a big jump in the minimum supported compiler version? >> >> 12.0.0-20210420 behaves the same. I just chose 17 because that was >> convenient to try first. > >Are you also advocating ditching the single-byte cmpxchg() emulation? >If the compiler really can handle this emulation for all sizes on all >supported compilers on all affected architectures, that is actually not >at all an unattractive approach. Well that would be "not long lasting effort" 2024-2026... Hmm.. > > Thanx, Paul --- Thanks! https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/