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b=vH95IIdH1a1hS7FTFrWes5ZDLADqVcRGqzS1IFnydyeFkwzEcZarrCiRD8xYQXusg eMBHA7BTXap7elW+bD+pNwlYp8GIJzhHm1LFS+dkv7vBns40c6OI+8u1kujR36WQYs kQ0Fl1vaSNds5gK5BSBR2gZh4YS2BBpeZCVd3KE0= Date: Thu, 30 Apr 2026 09:34:23 -0700 From: Andrew Morton To: Michal Hocko Cc: Minchan Kim , hca@linux.ibm.com, linux-s390@vger.kernel.org, david@kernel.org, brauner@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, surenb@google.com, timmurray@google.com Subject: Re: [PATCH v2] mm: process_mrelease: introduce PROCESS_MRELEASE_REAP_KILL flag Message-Id: <20260430093423.3118ff0f295a9719cdadd91a@linux-foundation.org> In-Reply-To: References: <20260429211359.3829683-1-minchan@kernel.org> <20260430074305.9d3389ed71af040acfe222de@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: gj1yge976a3c9hw1t4wexubeqceieeu9 X-Rspam-User: X-Rspamd-Queue-Id: E84EFC0004 X-Rspamd-Server: rspam07 X-HE-Tag: 1777566864-411136 X-HE-Meta: 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 X7n01nS4 c42xAmhAAiF+FvYv8PLW7joKjQ6tTG0LXU7beB3Wc+kYmIgo6Q2Pse8QOev+sRJuOQGFAJU1ihesdxT9+f4xzXsgkdEZIMMhKQ51dSX0Z7fxUxobXjh2lYMlS8cw0ABPXmJeMVqCKSXiQ41GP9yGDIGD6/dIa+PFdcGGtZSeZ3oqLMpHZo7gIajMEJG914hYJ9eXvPIyGWWCFHwEQ31GHxvJN5lpOIlXSZcfLs0TqnlQLNLweIDUYhDOXXEQBp5vzSKzDMDFqcMT+qArDmK0ysFP2lABoHMWjZYPlh9O/VOENhZsrra6SDt7dQkjFjpFUxMjql3sXwQMtK5daImv3anMKgFjJJFD2pnUHjNWIDVygVfgimP4Kq3YmbBSdPUGqliEBuvwm5E1butLeDcZ7XYM4zgQgM5sTc4fSryV9RkfSgGQpdfSJk3abRA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 30 Apr 2026 17:32:40 +0200 Michal Hocko wrote: > On Thu 30-04-26 07:43:05, Andrew Morton wrote: > > On Wed, 29 Apr 2026 14:13:59 -0700 Minchan Kim wrote: > > > > > Currently, process_mrelease() requires userspace to send a SIGKILL signal > > > prior to invocation. This separation introduces a scheduling race window > > > where the victim task may receive the signal and enter the exit path > > > before the reaper can invoke process_mrelease(). > > > > Does process_mrelease() have a manpage? My googling was a fail. > > It does. Very well hidden in 884a7e5964e06 Well, that didn't appear to make it into the manpages project and it doesn't describe the expected usage: need to kill the process first. But I guess all the needed info is in tools/testing/selftests/mm/mrelease_test.c. https://lwn.net/Articles/864184/ is useful.