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Fri, 9 Feb 2024 23:13:06 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id JZl0DoKxxmVKfwAAD6G6ig (envelope-from ); Fri, 09 Feb 2024 23:13:06 +0000 Date: Sat, 10 Feb 2024 00:14:13 +0100 From: Oscar Salvador To: Marco Elver Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Vlastimil Babka , Andrey Konovalov , Alexander Potapenko Subject: Re: [PATCH v7 3/4] mm,page_owner: Display all stacks and their count Message-ID: References: <20240208234539.19113-1-osalvador@suse.de> <20240208234539.19113-4-osalvador@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Level: Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=UtV1+l5i; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=YfD8xwCX X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Spamd-Result: default: False [-3.22 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM_LONG(-1.00)[-1.000]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+]; MX_GOOD(-0.01)[]; RCPT_COUNT_SEVEN(0.00)[8]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; NEURAL_HAM_SHORT(-0.04)[-0.181]; FREEMAIL_CC(0.00)[linux-foundation.org,vger.kernel.org,kvack.org,suse.com,suse.cz,gmail.com,google.com]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-1.87)[94.27%] X-Spam-Score: -3.22 X-Rspamd-Queue-Id: C59FE1F836 X-Spam-Flag: NO On Fri, Feb 09, 2024 at 10:52:48PM +0100, Oscar Salvador wrote: > Thinking about it some more, I think I made a mistake: > > I am walking all buckets, and within those buckets there are not only > page_owner stack_records, which means that I could return a stack_record > from e.g: KASAN (which I think can evict stack_records) and then > everything goes off the rails. > Which means I cannot walk the buckets like that. > > Actually, I think that having something like the following > > struct list_stack_records { > struct stack_record *stack; > struct list_stack_records *next; > } Or, I could use the extra_bits field from handle_parts to flag that when a depot_stack_handle_t is used by page_owner. Then __stack_depot_get_next_stack_record() would check whether a stack_record->handle.extra_bits has the page_owner bit, and only return those stacks that have such bit. This would solve the problem of returning a potentially evictable stack , only by returning page_owner's stack_records, and I would not have to maintain my own list. I yet have to see how that would look like, but sounds promising. Do you think that is feasible Marco? Thanks -- Oscar Salvador SUSE Labs