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[198.145.29.99]) by mx.google.com with ESMTPS id b1si768347pgq.72.2019.03.14.20.16.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Mar 2019 20:16:48 -0700 (PDT) Received-SPF: pass (google.com: domain of srs0=vfcv=rs=goodmis.org=rostedt@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; spf=pass (google.com: domain of srs0=vfcv=rs=goodmis.org=rostedt@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom="SRS0=VfCv=RS=goodmis.org=rostedt@kernel.org" Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F404321873; Fri, 15 Mar 2019 03:16:45 +0000 (UTC) Date: Thu, 14 Mar 2019 23:16:41 -0400 From: Steven Rostedt To: Sultan Alsawaf Cc: Joel Fernandes , Tim Murray , Michal Hocko , Suren Baghdasaryan , Greg Kroah-Hartman , Arve =?UTF-8?B?SGrDuG5uZXbDpWc=?= , Todd Kjos , Martijn Coenen , Christian Brauner , Ingo Molnar , Peter Zijlstra , LKML , "open list:ANDROID DRIVERS" , linux-mm , kernel-team Subject: Re: [RFC] simple_lmk: Introduce Simple Low Memory Killer for Android Message-ID: <20190314231641.5a37932b@oasis.local.home> In-Reply-To: <20190314204911.GA875@sultan-box.localdomain> References: <20190310203403.27915-1-sultan@kerneltoast.com> <20190311174320.GC5721@dhcp22.suse.cz> <20190311175800.GA5522@sultan-box.localdomain> <20190311204626.GA3119@sultan-box.localdomain> <20190312080532.GE5721@dhcp22.suse.cz> <20190312163741.GA2762@sultan-box.localdomain> <20190314204911.GA875@sultan-box.localdomain> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: On Thu, 14 Mar 2019 13:49:11 -0700 Sultan Alsawaf wrote: > Perhaps I'm missing something, but if you want to know when a process has died > after sending a SIGKILL to it, then why not just make the SIGKILL optionally > block until the process has died completely? It'd be rather trivial to just > store a pointer to an onstack completion inside the victim process' task_struct, > and then complete it in free_task(). How would you implement such a method in userspace? kill() doesn't take any parameters but the pid of the process you want to send a signal to, and the signal to send. This would require a new system call, and be quite a bit of work. If you can solve this with an ebpf program, I strongly suggest you do that instead. -- Steve