From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 F0E1E324B02 for ; Tue, 2 Sep 2025 13:45:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820751; cv=none; b=CT+fODLnYtTiVUHe7DeH2ohaszFKOstpbcB2s4rCEfmIxgaFWMNHSeRME/RVKLkjnXg1yOVdZ0fNk32AKvMeJjf+2FBG2ZdB3/x4e9BNEalZyZpqnGwpYjCRkDGWes3j11etiNqgjpb5CJsAuplIJCu3w5JS5Q2VVYE8PBdBbbM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820751; c=relaxed/simple; bh=+oyr6TNfvEGai2tHmAsMUdGK0F86ufk1C332gGol6rY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=mbpLK0KVPcDflxbAVZWhW/E1R9AYiqrk3QjBfI7UKEn73wCm+kI3hLuJUm+t4F7as/nOk/4fb4oSdq686ueWq7A395r/bt6ECiRHLthf+JpXRjiekeuG5a0GUsGkPNbT34y396fy6EpbeUhoijehR/kKmZjdh1KAMtNCYt1b37g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=xYH31KQJ; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=9o6DWhKI; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="xYH31KQJ"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="9o6DWhKI" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1756820747; 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=U9p+nRb5XuklUSbmdiKjvuliV6oCMcyIA3bYHogG/hI=; b=xYH31KQJQWE9xHHPJQ1ckWr4op3pOXfgt6KT43WmOIaRzQ+zmXsyz1yj9QchEeTRFo2tgX 58HGHCY+v38+0YmCGpEBiGrSp9V5ickUX4Le63Ay1VnPQp3HTFrGNJYrUfi4zU9vfgU0Wz kKfsHw9cTPN/NAOxZ330/c/ZUn4GDp9P/Iz/4F9QVQIUZZC70LGQTajLXS234i22he9TN9 RhN/2v9qV6oYSS4Yg2iwm7IS9Q5ricH9JN/2wWuMgJWwYdh/aoRzbRjyfs70tfFMGYuUwS diPhYtPsy2Zy3SKQ7BzItdRO+NgaVvxCh6nIecbqObjUdls6UbK0aL3RUJIibA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1756820747; 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=U9p+nRb5XuklUSbmdiKjvuliV6oCMcyIA3bYHogG/hI=; b=9o6DWhKIGFSnvfbB0dVda1gbe3FmcoDY7qbzyU/RL73M2vFW24dbgTOx57RKWRW6eOWYTR 2jzpWZFcr3O23KAQ== To: Mathieu Desnoyers , LKML Cc: Jens Axboe , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Paolo Bonzini , Sean Christopherson , Wei Liu , Dexuan Cui , x86@kernel.org, Arnd Bergmann , Heiko Carstens , Christian Borntraeger , Sven Schnelle , Huacai Chen , Paul Walmsley , Palmer Dabbelt Subject: Re: [patch V2 09/37] rseq: Introduce struct rseq_event In-Reply-To: <9a94b9d4-708c-476a-bf7d-7deb1c14f1ac@efficios.com> References: <20250823161326.635281786@linutronix.de> <20250823161653.843757955@linutronix.de> <9a94b9d4-708c-476a-bf7d-7deb1c14f1ac@efficios.com> Date: Tue, 02 Sep 2025 15:45:44 +0200 Message-ID: <87jz2h0xyv.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Mon, Aug 25 2025 at 14:11, Mathieu Desnoyers wrote: >> + * @sched_switch: True if the task was scheduled out >> + * @has_rseq: True if the task has a rseq pointer installed >> + */ >> +struct rseq_event { >> + union { >> + u32 all; >> + struct { >> + union { >> + u16 events; >> + struct { >> + u8 sched_switch; >> + }; > > Is alpha still supported, or can we assume bytewise loads/stores ? Alpha is on life support, but that does not mean we have to cater for it in new features. > Are those events meant to each consume 1 byte (which limits us to 2 > events for a 2-byte "events"/4-byte "all"), or is the plan to update > them with bitwise or/~ and ? No. Bitwise or/and is creating horrible ASM code and needs serialization in the worst case. There is a no need for tons of events. See changes further down the series. Thanks, tglx