From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B1AB9371056; Mon, 23 Feb 2026 21:56:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771883778; cv=none; b=Tdx/NZW/sMD3y5eNNw1X69BmMc2t4o114Bs6JDovKsn533id01q4kbOkXI2Rd7XlORZzYQc2G9mRb7h1q+LGdbH1fjNTRBwrXzBADTGIyPET9+dHvk3MMxH3uzCZXUvQmIfPn7tjv3zFRZ5zn/6MPLvU/phkWvMFjOm/TrLxxbo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771883778; c=relaxed/simple; bh=fQIHqy1M3EnBsPkSeluvFe+CzPVvJ3xbr05GGxDh4vI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Z89UsaEMIIJTvEP0O8gVGqXvOZU/aP8L05CxLIeT6jh6IeoYL2MHwS2y5aSlMqjE19TRwNmwE11IkX2HXAuk0YY1UTq6iE82Pwl0j15ARgIzi0o5g56NkDd4GF5Qw5v6s7Ydnaw4V7t9EVUVt3Ur9rREoyFcgcYJtIWx5nRs62k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SiAryGDr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SiAryGDr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 057A9C116C6; Mon, 23 Feb 2026 21:56:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771883778; bh=fQIHqy1M3EnBsPkSeluvFe+CzPVvJ3xbr05GGxDh4vI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SiAryGDrkCovEn2j4uohrVDXWPiJmV5sCYkegexSkKYuWS7Yab9U+c2yQqqySi1JH 2NH6LIJtP4os/QTlmf6YFUQh54Spl58Pu3l46yBCu06ZnvYyJ0YrZKh+QRk8lzd5xz VsdkZXiJJ6JE8Qot2esjDx2JlBqtXQLNg1DzTZBwR1SVM7ATEbSFyFr83t+gaYcfA9 QcHHQNoEWnnCN//JfpsBuAlpojl35ab99z4OTP6BCVNEXqL+3LEgRix9DdCf+cldgC sN9lkIDZYIAEqs5csxHzG5yfxJukTaUYLnpjn8Ss+xHvjKtgaE5uflauArFrZecsvD HZIjIX4/x7wlg== Date: Mon, 23 Feb 2026 22:56:15 +0100 From: Frederic Weisbecker To: Michal Hocko Cc: Marcelo Tosatti , Leonardo Bras , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Leonardo Bras , Thomas Gleixner , Waiman Long , Boqun Feng , Frederic Weisbecker Subject: Re: [PATCH 0/4] Introduce QPW for per-cpu operations Message-ID: References: <20260206143430.021026873@redhat.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Le Thu, Feb 19, 2026 at 08:30:31PM +0100, Michal Hocko a écrit : > On Thu 19-02-26 12:27:23, Marcelo Tosatti wrote: > > Michal, > > > > Again, i don't see how moving operations to happen at return to > > kernel would help (assuming you are talking about > > "context_tracking,x86: Defer some IPIs until a user->kernel transition"). > > Nope, I am not talking about IPIs, although those are an example of pcp > state as well. I am sorry I do not have a link handy, I am pretty sure > Frederic will have that. Another example, though, was vmstat flushes > that need to be pcp. There are many other examples. Here it is: https://lore.kernel.org/all/20250410152327.24504-1-frederic@kernel.org/ Thanks. -- Frederic Weisbecker SUSE Labs