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Mon, 18 Aug 2025 12:04:22 +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 4nltAMYWo2iqbAAAD6G6ig (envelope-from ); Mon, 18 Aug 2025 12:04:22 +0000 Message-ID: <47277451-4220-436a-a2ef-b0a58d556c4f@suse.de> Date: Mon, 18 Aug 2025 14:04:21 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/5] mm: add largest_zero_folio() routine To: "Pankaj Raghav (Samsung)" , Suren Baghdasaryan , Ryan Roberts , Baolin Wang , Vlastimil Babka , Zi Yan , Mike Rapoport , Dave Hansen , Michal Hocko , David Hildenbrand , Lorenzo Stoakes , Andrew Morton , Thomas Gleixner , Nico Pache , Dev Jain , "Liam R . Howlett" , Jens Axboe Cc: linux-kernel@vger.kernel.org, willy@infradead.org, linux-mm@kvack.org, Ritesh Harjani , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Darrick J . Wong" , mcgrof@kernel.org, gost.dev@samsung.com, hch@lst.de, Pankaj Raghav References: <20250808121141.624469-1-kernel@pankajraghav.com> <20250808121141.624469-5-kernel@pankajraghav.com> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <20250808121141.624469-5-kernel@pankajraghav.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; TO_DN_SOME(0.00)[]; RCPT_COUNT_TWELVE(0.00)[28]; TAGGED_RCPT(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; R_RATELIMIT(0.00)[to_ip_from(RL5eeoi1u38ap3bcc41xiargsg)]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[vger.kernel.org,infradead.org,kvack.org,gmail.com,kernel.org,samsung.com,lst.de]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:mid,imap1.dmz-prg2.suse.org:helo] X-Spam-Flag: NO X-Spam-Score: -2.80 On 8/8/25 14:11, Pankaj Raghav (Samsung) wrote: > From: Pankaj Raghav > > The callers of mm_get_huge_zero_folio() have access to a mm struct and > the lifetime of the huge_zero_folio is tied to the lifetime of the mm > struct. > > largest_zero_folio() will give access to huge_zero_folio when > PERSISTENT_HUGE_ZERO_FOLIO config option is enabled for callers that do not > want to tie the lifetime to a mm struct. This is very useful for > filesystem and block layers where the request completions can be async > and there is no guarantee on the mm struct lifetime. > > This function will return a ZERO_PAGE folio if PERSISTENT_HUGE_ZERO_FOLIO > is disabled or if we failed to allocate a huge_zero_folio during early > init. > > Co-developed-by: David Hildenbrand > Signed-off-by: David Hildenbrand > Signed-off-by: Pankaj Raghav > --- > include/linux/huge_mm.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich