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 5FED31DF265 for ; Thu, 20 Feb 2025 16:19:14 +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=1740068355; cv=none; b=I7Tn9/sw2FVXK2a8ivMDWrBbIzRFMBLATm2raAp3tSZbYi8jRKZy+GgnySu9ahtGalV6xvVu/yMpha70xsTe5gK2YqIQ+CirR/Dmc0VvxM8LxkMs5LsITZDgqKX6vzodYU88mJhnhPwoH9plnzjatGZVMxmBwiZAIs7P80tFwbw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740068355; c=relaxed/simple; bh=fFp8FJUokY1RmBp2mB7uX3L0RMS9vV9hiRF7+rlAn4c=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=rqGmIsON/Pen+PZ8u6zGcoas5jWF/lsDDQsS4wgwgm7oFJzqsZvPJeCGaA0/ENusjmOZ1Cpi0reXOof3gwFrIEhNy107DikXvDgb1DtpkDyJh6K4nUusNvj0jaWyPFZBA6tm0NZONmcor/XwO2O5r8uoB7Z/XECplQoyBI2f1Jk= 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=en1ePuD/; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=ADOby/gp; 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="en1ePuD/"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="ADOby/gp" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1740068352; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JZ8WaAnDe7dn++wovr9Ki58qKgf9SgP+VlQv0BT4iZA=; b=en1ePuD/ennCbo3JTlznH30FweKS0IvBx8N2PLffzMcFvHhi/Vusd87M+qt4iydxhzaIVf bi3/wS/iCXvhzsexurNnQ+ig0ZRDBCsuZRh9xS19GkOv4c8yt5M20RBHDm1ejEOI6Q06Cg edYU5ZKtskXzIOc9jO0TAu9T9kdV99vZNWEgpRMvMnahfsRC/r6sN333kzD5Pr81cpacbz 8aDskQSACnKeoSNHuhYkrWPv48UaivREvNRzeKERdjMKvAi3URnUz+RjWiXlPGW164joU1 sFdskSNldy0KhdB7TnocN9o+t84rWsS7Xj8MVMt5ljkpdfSJzZ+w3NmD4jFsXg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1740068352; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JZ8WaAnDe7dn++wovr9Ki58qKgf9SgP+VlQv0BT4iZA=; b=ADOby/gpz3WJfQ3cu68XYbAr3xFAh5oM0wmO32oQlXaEgUrKzayNnuZ6psRDBqCP3XK3aR rzrdE8qplNEwukAw== To: Eric Dumazet Cc: Anna-Maria Behnsen , Frederic Weisbecker , linux-kernel , Benjamin Segall , Eric Dumazet Subject: Re: [PATCH V2 1/4] posix-timers: Make next_posix_timer_id an atomic_t In-Reply-To: References: <20250219125522.2535263-1-edumazet@google.com> <20250219125522.2535263-2-edumazet@google.com> <87wmdlhwa8.ffs@tglx> <87h64oiuey.ffs@tglx> <8734g8it5m.ffs@tglx> Date: Thu, 20 Feb 2025 17:19:11 +0100 Message-ID: <87wmdkh9mo.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; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Thu, Feb 20 2025 at 16:55, Eric Dumazet wrote: > On Thu, Feb 20, 2025 at 3:32=E2=80=AFPM Thomas Gleixner wrote: >> >> On Thu, Feb 20 2025 at 15:04, Thomas Gleixner wrote: >> > On Thu, Feb 20 2025 at 09:49, Eric Dumazet wrote: >> >> On Thu, Feb 20, 2025 at 9:09=E2=80=AFAM Thomas Gleixner wrote: >> >>> > This allows the following patch to use RCU. >> >>> >> >>> Your patch ordering is slightly off by two :) >> >>> >> >>> And it fails to explain for what RCU can be used.... >> >> >> >> This is explained in the following patches. >> > >> > The changelog of a patch has to be self contained. The 'following patc= h' >> > has no meaning when the patch is merged. >> >> That said, please just fold this into the patch which actually does this= RCU >> lookup upfront. The change is trivial enough that it does not really >> require to be seperate. If the lockless increment would cause issues, >> then the subsequent RCU lookup is the least of the worries :) > > I can squash all patches into a single one if you prefer. Please don't. The wraparound race prevention has nothing to do with the lookup optimization. Thanks, tglx