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Tue, 21 Apr 2026 07:29:53 +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 h3awB3En52n4KQAAD6G6ig (envelope-from ); Tue, 21 Apr 2026 07:29:53 +0000 Date: Tue, 21 Apr 2026 09:29:43 +0200 From: Oscar Salvador To: Muchun Song Cc: Muchun Song , Andrew Morton , David Hildenbrand , Michael Ellerman , Madhavan Srinivasan , Mike Rapoport , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Nicholas Piggin , Christophe Leroy , aneesh.kumar@linux.ibm.com, joao.m.martins@oracle.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 4/4] mm/mm_init: Fix pageblock migratetype for ZONE_DEVICE compound pages Message-ID: References: <20260421022044.1217503-1-songmuchun@bytedance.com> <20260421022044.1217503-5-songmuchun@bytedance.com> <9343F329-BCD4-4D64-94CB-A94F0E9E4400@linux.dev> 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: <9343F329-BCD4-4D64-94CB-A94F0E9E4400@linux.dev> X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; ARC_NA(0.00)[]; RCPT_COUNT_TWELVE(0.00)[19]; MIME_TRACE(0.00)[0:+]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FREEMAIL_CC(0.00)[bytedance.com,linux-foundation.org,kernel.org,ellerman.id.au,linux.ibm.com,oracle.com,google.com,suse.com,gmail.com,kvack.org,lists.ozlabs.org,vger.kernel.org]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; MISSING_XM_UA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:email,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Rspamd-Action: no action X-Spam-Flag: NO X-Spam-Score: -4.51 X-Spam-Level: X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 1D01F5BCDE On Tue, Apr 21, 2026 at 02:54:35PM +0800, Muchun Song wrote: > > > > On Apr 21, 2026, at 12:15, Oscar Salvador wrote: > > > > On Tue, Apr 21, 2026 at 10:20:44AM +0800, Muchun Song wrote: > >> The memmap_init_zone_device() function only initializes the migratetype > >> of the first pageblock of a compound page. If the compound page size > >> exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), > >> subsequent pageblocks in the compound page remain uninitialized. > >> > >> Move the migratetype initialization out of __init_zone_device_page() > >> and into a separate pageblock_migratetype_init_range() function. This > >> iterates over the entire PFN range of the memory, ensuring that all > >> pageblocks are correctly initialized. > >> > >> Fixes: c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages") > >> Signed-off-by: Muchun Song > >> Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Oscar Salvador > > Would not the call to __init_zone_device_page() from > > memmap_init_compound() take care of the subsequent pageblocks? > > > > No, it won't handle them automatically, as the page count from > compound_nr_pages doesn't cover the following pageblocks. Ok, I see. -- Oscar Salvador SUSE Labs