From: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
To: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, david@fromorbit.com,
chandan.babu@oracle.com, akpm@linux-foundation.org,
mcgrof@kernel.org, ziy@nvidia.com, hare@suse.de,
djwong@kernel.org, gost.dev@samsung.com, linux-mm@kvack.org,
willy@infradead.org, Pankaj Raghav <p.raghav@samsung.com>
Subject: [PATCH 02/13] fs: Allow fine-grained control of folio sizes
Date: Mon, 26 Feb 2024 10:49:25 +0100 [thread overview]
Message-ID: <20240226094936.2677493-3-kernel@pankajraghav.com> (raw)
In-Reply-To: <20240226094936.2677493-1-kernel@pankajraghav.com>
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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) <willy@infradead.org>
Co-developed-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
include/linux/pagemap.h | 100 ++++++++++++++++++++++++++++++++--------
1 file changed, 80 insertions(+), 20 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 2df35e65557d..fc8eb9c94e9c 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 +349,47 @@ 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_min_order() - Set the minimum folio order
+ * @mapping: The address_space.
+ * @min: Minimum folio order (between 0-MAX_PAGECACHE_ORDER inclusive).
+ *
+ * The filesystem should call this function in its inode constructor to
+ * indicate which base size 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_min_order(struct address_space *mapping,
+ unsigned int min)
+{
+ if (min > MAX_PAGECACHE_ORDER)
+ min = MAX_PAGECACHE_ORDER;
+
+ mapping->flags = (mapping->flags & ~AS_FOLIO_ORDER_MASK) |
+ (min << AS_FOLIO_ORDER_MIN) |
+ (MAX_PAGECACHE_ORDER << AS_FOLIO_ORDER_MAX);
+}
+
/**
* 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 +400,37 @@ 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_min_order(mapping, 0);
+}
+
+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 +440,7 @@ 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 +601,6 @@ 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
--
2.43.0
next prev parent reply other threads:[~2024-02-26 9:49 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-26 9:49 [PATCH 00/13] enable bs > ps in XFS Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 01/13] mm: Support order-1 folios in the page cache Pankaj Raghav (Samsung)
2024-02-26 9:49 ` Pankaj Raghav (Samsung) [this message]
2024-02-26 9:49 ` [PATCH 03/13] filemap: align the index to mapping_min_order " Pankaj Raghav (Samsung)
2024-02-26 14:40 ` Matthew Wilcox
2024-02-27 10:06 ` Pankaj Raghav (Samsung)
2024-02-27 16:22 ` Kent Overstreet
2024-02-27 16:36 ` Pankaj Raghav (Samsung)
2024-02-27 16:40 ` Kent Overstreet
2024-02-27 16:55 ` Pankaj Raghav (Samsung)
2024-02-27 17:02 ` Kent Overstreet
2024-02-27 17:09 ` Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 04/13] filemap: use mapping_min_order while allocating folios Pankaj Raghav (Samsung)
2024-02-26 14:47 ` Matthew Wilcox
2024-02-27 12:09 ` Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 05/13] readahead: set file_ra_state->ra_pages to be at least mapping_min_order Pankaj Raghav (Samsung)
2024-02-26 14:49 ` Matthew Wilcox
2024-02-27 12:42 ` Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 06/13] readahead: align index to mapping_min_order in ondemand_ra and force_ra Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 07/13] readahead: rework loop in page_cache_ra_unbounded() Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 08/13] readahead: allocate folios with mapping_min_order in ra_(unbounded|order) Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 09/13] mm: do not split a folio if it has minimum folio order requirement Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 10/13] iomap: fix iomap_dio_zero() for fs bs > system page size Pankaj Raghav (Samsung)
2024-02-26 17:58 ` Matthew Wilcox
2024-02-27 9:33 ` Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 11/13] xfs: expose block size in stat Pankaj Raghav (Samsung)
2024-02-26 12:44 ` Dave Chinner
2024-02-27 8:53 ` Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 12/13] xfs: make the calculation generic in xfs_sb_validate_fsb_count() Pankaj Raghav (Samsung)
2024-02-26 12:47 ` Dave Chinner
2024-02-26 13:21 ` Matthew Wilcox
2024-02-27 8:44 ` Pankaj Raghav (Samsung)
2024-02-26 9:49 ` [PATCH 13/13] xfs: enable block size larger than page size support Pankaj Raghav (Samsung)
2024-02-26 13:26 ` Matthew Wilcox
2024-02-26 21:18 ` Dave Chinner
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