From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 7EA5339B947 for ; Tue, 17 Mar 2026 08:28:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773736144; cv=none; b=iXw8GVxzw5bgORxcr6bfxnupBnxE08U2FM4xMNevuT8F23FWfXNMD7NYsB4EwEqUtNvthWDsj3SELMxbmP5BAGjS70tHw2B4pFk7z7SLhj+/JU5WTX/rWDHj1jB5OvgZKazGV15Z4jCZE2VNq9qe9vfAy/E+LfSZ/bUqGUj233w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773736144; c=relaxed/simple; bh=QQFLJHUmHs0qhSiAw8QQ1BQKhdBHNFNeCWBkYyAeYAc=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=UIaOlVI2zsQ98BrsTbGLa64QgTYovtSNmut5qSRb6F1MOM2ZDMG86+ZmNfrs5YWjJjREqhiJWd/zhHPUZRaAnzJ0w/65cSxKI4O5VZr1s/NsB0zMfsRLO6S2PzAL8D6Gt0Lz5zFLJ5DnVa5r8eSejxE8KpKePYUDw0td2xGg+p0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=VS9Qpy8L; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VS9Qpy8L" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773736138; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=E1i4JrRd8RgUFG2P21MNhAf58JV2p2RcSymdj6yfJlM=; b=VS9Qpy8LxDJdOHyLqm9yjZ/ppzC+x+icQZ9kMxPHjMHVPtG9pz/G3QR3zhUTDQ1aOno836 jF7xzbZ4poMJyhCxScHU652WodizEVF+jzoeLRDhr9mZRk+aJN/2ZOcBXeCCfxd43DLeXF MwV/EYs1ny4bqbylpDkcK4/U9Y5l5DI= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-245-P_gCM46HNAKMzdTYo0d1GA-1; Tue, 17 Mar 2026 04:28:54 -0400 X-MC-Unique: P_gCM46HNAKMzdTYo0d1GA-1 X-Mimecast-MFC-AGG-ID: P_gCM46HNAKMzdTYo0d1GA_1773736133 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E76ED1801334; Tue, 17 Mar 2026 08:28:50 +0000 (UTC) Received: from fweimer-oldenburg.csb.redhat.com (unknown [10.45.224.103]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2E77618001FE; Tue, 17 Mar 2026 08:28:44 +0000 (UTC) From: Florian Weimer To: Thomas Gleixner Cc: LKML , Mathieu Desnoyers , =?utf-8?Q?Andr=C3=A9?= Almeida , Sebastian Andrzej Siewior , Carlos O'Donell , Peter Zijlstra , Rich Felker , Torvald Riegel , Darren Hart , Ingo Molnar , Davidlohr Bueso , Arnd Bergmann , "Liam R . Howlett" Subject: Re: [patch 8/8] x86/vdso: Implement __vdso_futex_robust_try_unlock() In-Reply-To: <20260316164951.484640267@kernel.org> (Thomas Gleixner's message of "Mon, 16 Mar 2026 18:13:34 +0100") References: <20260316162316.356674433@kernel.org> <20260316164951.484640267@kernel.org> Date: Tue, 17 Mar 2026 09:28:41 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 * Thomas Gleixner: > Arguably this could be avoided by providing separate functions and making > the IP range for the quick check in the exit to user path cover the whole > text section which contains the two functions. But that's not a win at all > because: > > 1) User space needs to handle the two variants instead of just > relying on a bit which can be saved in the mutex at > initialization time. I'm pretty sure that on the user-space side, we wouldn't have cross-word-size operations (e.g., 64-bit code working on both 64-bit and 32-bit robust mutexes). Certainly not within libcs. The other point about complexity is of course still valid. Thanks, Florian