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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> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Queue-Id: B632640005 X-Stat-Signature: jbx7twmez6zndbykfwmrb88ixkqniu84 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1771883779-417788 X-HE-Meta: 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 uVZxAkJa UCsq5OXAzDaZg6QubcdFOquzKgnIM/b1MVLvwsTMBOwBSbtEYbKE7DYH4JC6qdM9NuElz3ajlkUbdTJ/unhDjsFdbCoL6mZ7fSGljtELAqUeWHnYsSUsOEj1cmd8Qxkz7iuKtRXr+oo/dwr3vsPPOn7jLW9Z8DLV3EKriWWIcWp/N9vOJsjTmFrJBXb6qVHTgQ3HqualAWC65BCDT0KqXWDHK5MbtvvcJuXUUj7dapOl+CRVCK0poM2eqzbCqt7V1YOZ47TjzUZLxRUvbVcHdaWlhX9zeGspmkLKUmGI79hKAPoRN6l+TyEaH2K2us/CAaUTFWU/vuxYXhG0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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