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Thu, 25 Apr 2024 13:37:59 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1714045079; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jwJiip//T+O8iHQnA8gIdy4HYh6WY6jnyehEbs5RfBY=; b=pWAvZZwLeRk248TadAtN1GDZWGqpWPg8DxfyFHbfGEdom2wHzQIoOrmK+RQpww2eBjxVN/ NlABjkXV9Gjpd+TpwlZSMoEAu05F6/Mw4VOD8OXl16gp7AVgZDmbn+3JirgO4gTNK7Qe97 at1vhk5t49j7z4wFdFwJ/Dldj6xrKudEaXOAuO4oLHfIb9yVzFAL0V+XZQJgUZJ9H6r0qy FxHC6gBCJyRluZh7j4XHD5DtA2ibCeDlVPUZUmymb4Uc4Trh/a0cO91qysuPW5S6GYYYdF XWAd/YEqQ4QNgruuoeC/0NDR0mnB2XMeaVxFPNnWkok5yOpWkSpxnlMjW1Xs5A== From: "Pankaj Raghav (Samsung)" To: willy@infradead.org, djwong@kernel.org, brauner@kernel.org, david@fromorbit.com, chandan.babu@oracle.com, akpm@linux-foundation.org Cc: linux-fsdevel@vger.kernel.org, hare@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-xfs@vger.kernel.org, mcgrof@kernel.org, gost.dev@samsung.com, p.raghav@samsung.com Subject: [PATCH v4 02/11] fs: Allow fine-grained control of folio sizes Date: Thu, 25 Apr 2024 13:37:37 +0200 Message-Id: <20240425113746.335530-3-kernel@pankajraghav.com> In-Reply-To: <20240425113746.335530-1-kernel@pankajraghav.com> References: <20240425113746.335530-1-kernel@pankajraghav.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: E8AFD180003 X-Stat-Signature: 6swhhju6yz8wcwaakz81o8ss4mi5oth1 X-HE-Tag: 1714045082-707404 X-HE-Meta: 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 MZgPpAJl 0sFQoIrCW0LKyJZFLv5LOMv8UNPTG4Jn3dh12EWcMlz0P0e/NiUG0E4SwwpaSfEnNmywkWADhMux3ibs2wGjeVgmaIqklAiNgBjCWsYaHEG8sC0UGpOBIjzoJqHu8OHXR0RDD2QdEhcqmSTlC0n3F0bjveaKAJJiHSQ6GjX2yNuLidijqrkcm5ZB8qYdHh+IJZ6Tau/zpSmi84kvKP+PXnGqJOkOvDO8y1lYW9cEHEa5Vlapdm6KWRtmclocJHD7D1ip8SmbPfMSmq/NHawo/O1u+Q394U8TYrCBdp+EBYy95JNdSn92ZdmsBdQ== 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: List-Subscribe: List-Unsubscribe: From: "Matthew Wilcox (Oracle)" Some filesystems want to be able to ensure that folios that are added to the page cache are at least a certain size. Add mapping_set_folio_min_order() to allow this level of control. Signed-off-by: Matthew Wilcox (Oracle) Co-developed-by: Pankaj Raghav Signed-off-by: Pankaj Raghav Signed-off-by: Luis Chamberlain Reviewed-by: Hannes Reinecke Reviewed-by: Darrick J. Wong --- include/linux/pagemap.h | 116 +++++++++++++++++++++++++++++++++------- 1 file changed, 96 insertions(+), 20 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 2df35e65557d..2e5612de1749 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -202,13 +202,18 @@ enum mapping_flags { AS_EXITING = 4, /* final truncate in progress */ /* writeback related tags are not used */ AS_NO_WRITEBACK_TAGS = 5, - AS_LARGE_FOLIO_SUPPORT = 6, - AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */ - AS_STABLE_WRITES, /* must wait for writeback before modifying + AS_RELEASE_ALWAYS = 6, /* Call ->release_folio(), even if no private data */ + AS_STABLE_WRITES = 7, /* must wait for writeback before modifying folio contents */ - AS_UNMOVABLE, /* The mapping cannot be moved, ever */ + AS_FOLIO_ORDER_MIN = 8, + AS_FOLIO_ORDER_MAX = 13, /* Bit 8-17 are used for FOLIO_ORDER */ + AS_UNMOVABLE = 18, /* The mapping cannot be moved, ever */ }; +#define AS_FOLIO_ORDER_MIN_MASK 0x00001f00 +#define AS_FOLIO_ORDER_MAX_MASK 0x0003e000 +#define AS_FOLIO_ORDER_MASK (AS_FOLIO_ORDER_MIN_MASK | AS_FOLIO_ORDER_MAX_MASK) + /** * mapping_set_error - record a writeback error in the address_space * @mapping: the mapping in which an error should be set @@ -344,9 +349,63 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) m->gfp_mask = mask; } +/* + * There are some parts of the kernel which assume that PMD entries + * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then, + * limit the maximum allocation order to PMD size. I'm not aware of any + * assumptions about maximum order if THP are disabled, but 8 seems like + * a good order (that's 1MB if you're using 4kB pages) + */ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER +#else +#define MAX_PAGECACHE_ORDER 8 +#endif + +/* + * mapping_set_folio_order_range() - Set the folio order range + * @mapping: The address_space. + * @min: Minimum folio order (between 0-MAX_PAGECACHE_ORDER inclusive). + * @max: Maximum folio order (between @min-MAX_PAGECACHE_ORDER inclusive). + * + * The filesystem should call this function in its inode constructor to + * indicate which base size (min) and maximum size (max) of folio the VFS + * can use to cache the contents of the file. This should only be used + * if the filesystem needs special handling of folio sizes (ie there is + * something the core cannot know). + * Do not tune it based on, eg, i_size. + * + * Context: This should not be called while the inode is active as it + * is non-atomic. + */ +static inline void mapping_set_folio_order_range(struct address_space *mapping, + unsigned int min_order, + unsigned int max_order) +{ + if (min_order > MAX_PAGECACHE_ORDER) + min_order = MAX_PAGECACHE_ORDER; + + if (max_order > MAX_PAGECACHE_ORDER) + max_order = MAX_PAGECACHE_ORDER; + + max_order = max(max_order, min_order); + /* + * TODO: max_order is not yet supported in filemap. + */ + mapping->flags = (mapping->flags & ~AS_FOLIO_ORDER_MASK) | + (min_order << AS_FOLIO_ORDER_MIN) | + (max_order << AS_FOLIO_ORDER_MAX); +} + +static inline void mapping_set_folio_min_order(struct address_space *mapping, + unsigned int min) +{ + mapping_set_folio_order_range(mapping, min, MAX_PAGECACHE_ORDER); +} + /** * mapping_set_large_folios() - Indicate the file supports large folios. - * @mapping: The file. + * @mapping: The address_space. * * The filesystem should call this function in its inode constructor to * indicate that the VFS can use large folios to cache the contents of @@ -357,7 +416,37 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) */ static inline void mapping_set_large_folios(struct address_space *mapping) { - __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); + mapping_set_folio_order_range(mapping, 0, MAX_PAGECACHE_ORDER); +} + +static inline unsigned int mapping_max_folio_order(struct address_space *mapping) +{ + return (mapping->flags & AS_FOLIO_ORDER_MAX_MASK) >> AS_FOLIO_ORDER_MAX; +} + +static inline unsigned int mapping_min_folio_order(struct address_space *mapping) +{ + return (mapping->flags & AS_FOLIO_ORDER_MIN_MASK) >> AS_FOLIO_ORDER_MIN; +} + +static inline unsigned long mapping_min_folio_nrpages(struct address_space *mapping) +{ + return 1UL << mapping_min_folio_order(mapping); +} + +/** + * mapping_align_start_index() - Align starting index based on the min + * folio order of the page cache. + * @mapping: The address_space. + * + * Ensure the index used is aligned to the minimum folio order when adding + * new folios to the page cache by rounding down to the nearest minimum + * folio number of pages. + */ +static inline pgoff_t mapping_align_start_index(struct address_space *mapping, + pgoff_t index) +{ + return round_down(index, mapping_min_folio_nrpages(mapping)); } /* @@ -367,7 +456,7 @@ static inline void mapping_set_large_folios(struct address_space *mapping) static inline bool mapping_large_folio_support(struct address_space *mapping) { return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && - test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); + (mapping_max_folio_order(mapping) > 0); } static inline int filemap_nr_thps(struct address_space *mapping) @@ -528,19 +617,6 @@ static inline void *detach_page_private(struct page *page) return folio_detach_private(page_folio(page)); } -/* - * There are some parts of the kernel which assume that PMD entries - * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then, - * limit the maximum allocation order to PMD size. I'm not aware of any - * assumptions about maximum order if THP are disabled, but 8 seems like - * a good order (that's 1MB if you're using 4kB pages) - */ -#ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER -#else -#define MAX_PAGECACHE_ORDER 8 -#endif - #ifdef CONFIG_NUMA struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order); #else