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Mon, 24 Apr 2023 03:54:59 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id /PJrM5P9RWSUaAAAMHmgww (envelope-from ); Mon, 24 Apr 2023 03:54:59 +0000 MIME-Version: 1.0 Date: Mon, 24 Apr 2023 05:54:59 +0200 From: Oscar Salvador To: Alexander Potapenko Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Vlastimil Babka , Eric Dumazet , Waiman Long , Suren Baghdasaryan , Marco Elver , Andrey Konovalov Subject: Re: [PATCH v4 0/3] page_owner: print stacks and their counter In-Reply-To: References: <20230421101415.5734-1-osalvador@suse.de> User-Agent: Roundcube Webmail Message-ID: <7718244879ff2b696ea9cbb744cb3805@suse.de> X-Sender: osalvador@suse.de Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: A362640006 X-Rspamd-Server: rspam01 X-Stat-Signature: 15iwuwwob95oii9baf3dh6o6568tx7bm X-HE-Tag: 1682308501-653073 X-HE-Meta: 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 0vpL3FBQ IzcCnt72Ot7IyV9mWMhmvjl7fSNrjNkHLlH+/A+8R8lYeX1CnDeYTnh8ZqD94G5gNTQmu/BsmMT8gMQJHA4BFfm1o0gFfqm1lqXJZkw7A2KRPFPaqLmnQIm2zr5yPIv0Ykkg2IrguPwaC25MRS6MZ5N2V17kwUun9yQnmIw7xrH7eJ/LIE9T+Ml71ez5/TR/7Tn8x7k0Be2z76/8kEz/agofJnnFYkykGXELr0k+NuMhcrIQmnMyP6/QksE0RzMSeiF3AXWjN3lx4yqVKisTkDqRyUpGBcqbhk/UUL7cYAB8iXcwL6IJnox7JSQ== 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 2023-04-21 13:19, Alexander Potapenko wrote: > I think the implementation of these counters is too specific to > page_owner and is hard to use for any other purpose. > If we decide to have them, there should be no page_owner-specific > logic in the way we initialize/increment/decrement these counters. Another solution would be to always increment the refcount in __stack_depot_save, in this case the "page-owner" specific changes are gone, and it is more of a generic thing. e.g: Andrey Konovalov mentioned that in a future KASAN remodelation, he would be using a stack refcount as well. > The thresholds in "mm,page_owner: Filter out stacks by a threshold > counter" should also belong elsewhere. That can certainly be cleaned up I guess to not polute non-page_owner code. > Given that no other stackdepot user needs these counters, maybe it > should be cleaner to store an opaque struct along with the stack, > passing its size to stack_depot_save(), and letting users access it > directly using the stackdepot handler. > > I am also wondering if a separate hashtable mapping handlers to > counters would solve the problem for you? Let us see first if with the changes from above the code gets to a more generic and clean stage, if not we can explore further options. Thanks for your feedback Alexander! -- Oscar Salvador SUSE Labs