diff mbox series

[v13,01/10] fs: Allow fine-grained control of folio sizes

Message ID 20240822135018.1931258-2-kernel@pankajraghav.com (mailing list archive)
State Accepted, archived
Headers show
Series enable bs > ps in XFS | expand

Commit Message

Pankaj Raghav (Samsung) Aug. 22, 2024, 1:50 p.m. UTC 
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

We need filesystems to be able to communicate acceptable folio sizes
to the pagecache for a variety of uses (e.g. large block sizes).
Support a range of folio sizes between order-0 and order-31.

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>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: David Howells <dhowells@redhat.com>
---
 include/linux/pagemap.h | 90 ++++++++++++++++++++++++++++++++++-------
 mm/filemap.c            |  6 +--
 mm/readahead.c          |  4 +-
 3 files changed, 80 insertions(+), 20 deletions(-)

Comments

Daniel Gomez Aug. 23, 2024, 1:09 p.m. UTC | #1 
On Thu, Aug 22, 2024 at 03:50:09PM +0200, Pankaj Raghav (Samsung) wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> We need filesystems to be able to communicate acceptable folio sizes
> to the pagecache for a variety of uses (e.g. large block sizes).
> Support a range of folio sizes between order-0 and order-31.
> 
> 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>
> Reviewed-by: Hannes Reinecke <hare@suse.de>
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> Tested-by: David Howells <dhowells@redhat.com>
> ---
>  include/linux/pagemap.h | 90 ++++++++++++++++++++++++++++++++++-------
>  mm/filemap.c            |  6 +--
>  mm/readahead.c          |  4 +-
>  3 files changed, 80 insertions(+), 20 deletions(-)
> 
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index d9c7edb6422bd..c60025bb584c5 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -204,14 +204,21 @@ 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_INACCESSIBLE,	/* Do not attempt direct R/W access to the mapping,
> -				   including to move the mapping */
> +	AS_INACCESSIBLE = 8,	/* Do not attempt direct R/W access to the mapping */
> +	/* Bits 16-25 are used for FOLIO_ORDER */
> +	AS_FOLIO_ORDER_BITS = 5,
> +	AS_FOLIO_ORDER_MIN = 16,
> +	AS_FOLIO_ORDER_MAX = AS_FOLIO_ORDER_MIN + AS_FOLIO_ORDER_BITS,
>  };
>  
> +#define AS_FOLIO_ORDER_BITS_MASK ((1u << AS_FOLIO_ORDER_BITS) - 1)
> +#define AS_FOLIO_ORDER_MIN_MASK (AS_FOLIO_ORDER_BITS_MASK << AS_FOLIO_ORDER_MIN)
> +#define AS_FOLIO_ORDER_MAX_MASK (AS_FOLIO_ORDER_BITS_MASK << AS_FOLIO_ORDER_MAX)
> +#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
> @@ -367,9 +374,51 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
>  #define MAX_XAS_ORDER		(XA_CHUNK_SHIFT * 2 - 1)
>  #define MAX_PAGECACHE_ORDER	min(MAX_XAS_ORDER, PREFERRED_MAX_PAGECACHE_ORDER)
>  
> +/*
> + * mapping_set_folio_order_range() - Set the orders supported by a file.
> + * @mapping: The address space of the file.
> + * @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,
> +						 unsigned int max)
> +{
> +	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
> +		return;
> +
> +	if (min > MAX_PAGECACHE_ORDER)
> +		min = MAX_PAGECACHE_ORDER;
> +
> +	if (max > MAX_PAGECACHE_ORDER)
> +		max = MAX_PAGECACHE_ORDER;
> +
> +	if (max < min)
> +		max = min;
> +
> +	mapping->flags = (mapping->flags & ~AS_FOLIO_ORDER_MASK) |
> +		(min << AS_FOLIO_ORDER_MIN) | (max << AS_FOLIO_ORDER_MAX);

This is my test case to be sure we don't overwrite flags:

Before:
AS_FOLIO_ORDER_MASK=0x1f
AS_FOLIO_ORDER_MIN_MASK=0x1f0000
AS_FOLIO_ORDER_MAX_MASK=0x3e00000

v13:
AS_FOLIO_ORDER_BITS_MASK=0x1f
AS_FOLIO_ORDER_MASK=0x3ff0000
AS_FOLIO_ORDER_MIN_MASK=0x1f0000
AS_FOLIO_ORDER_MAX_MASK=0x3e00000
Test result for min=0, expected: min=0
Test result for min=0, expected: min=0
Test result for min=5, expected: min=5
Test result for min=10, expected: min=10
Test result for min=31, expected: min=31
Test result for min=31, expected: min=31
Test result for min=12, expected: min=12
Test result for min=20, expected: min=20
Test result for min=7, expected: min=7
Test result for min=14, expected: min=14

The test checks for flags in mapping_set_folio_order_range() and iterates over a
list of test cases:
	flags = 0xffffffff
	_flags = flags & ~(AS_FOLIO_ORDER_MASK)
	newflags = _flags | (min_val << AS_FOLIO_ORDER_MIN) | (max_val << AS_FOLIO_ORDER_MAX)


Reviewed-by: Daniel Gomez <da.gomez@samsung.com>

> +}
> +
> +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 of the file.
>   *
>   * The filesystem should call this function in its inode constructor to
>   * indicate that the VFS can use large folios to cache the contents of
> @@ -380,7 +429,23 @@ 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(const struct address_space *mapping)
> +{
> +	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
> +		return 0;
> +	return (mapping->flags & AS_FOLIO_ORDER_MAX_MASK) >> AS_FOLIO_ORDER_MAX;
> +}
> +
> +static inline unsigned int
> +mapping_min_folio_order(const struct address_space *mapping)
> +{
> +	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
> +		return 0;
> +	return (mapping->flags & AS_FOLIO_ORDER_MIN_MASK) >> AS_FOLIO_ORDER_MIN;
>  }
>  
>  /*
> @@ -389,20 +454,17 @@ static inline void mapping_set_large_folios(struct address_space *mapping)
>   */
>  static inline bool mapping_large_folio_support(struct address_space *mapping)
>  {
> -	/* AS_LARGE_FOLIO_SUPPORT is only reasonable for pagecache folios */
> +	/* AS_FOLIO_ORDER is only reasonable for pagecache folios */
>  	VM_WARN_ONCE((unsigned long)mapping & PAGE_MAPPING_ANON,
>  			"Anonymous mapping always supports large folio");
>  
> -	return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
> -		test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
> +	return mapping_max_folio_order(mapping) > 0;
>  }
>  
>  /* Return the maximum folio size for this pagecache mapping, in bytes. */
> -static inline size_t mapping_max_folio_size(struct address_space *mapping)
> +static inline size_t mapping_max_folio_size(const struct address_space *mapping)
>  {
> -	if (mapping_large_folio_support(mapping))
> -		return PAGE_SIZE << MAX_PAGECACHE_ORDER;
> -	return PAGE_SIZE;
> +	return PAGE_SIZE << mapping_max_folio_order(mapping);
>  }
>  
>  static inline int filemap_nr_thps(struct address_space *mapping)
> diff --git a/mm/filemap.c b/mm/filemap.c
> index d87c858465962..5c148144d5548 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1932,10 +1932,8 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
>  		if (WARN_ON_ONCE(!(fgp_flags & (FGP_LOCK | FGP_FOR_MMAP))))
>  			fgp_flags |= FGP_LOCK;
>  
> -		if (!mapping_large_folio_support(mapping))
> -			order = 0;
> -		if (order > MAX_PAGECACHE_ORDER)
> -			order = MAX_PAGECACHE_ORDER;
> +		if (order > mapping_max_folio_order(mapping))
> +			order = mapping_max_folio_order(mapping);
>  		/* If we're not aligned, allocate a smaller folio */
>  		if (index & ((1UL << order) - 1))
>  			order = __ffs(index);
> diff --git a/mm/readahead.c b/mm/readahead.c
> index e83fe1c6e5acd..e0cf3bfd2b2b3 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -449,10 +449,10 @@ void page_cache_ra_order(struct readahead_control *ractl,
>  
>  	limit = min(limit, index + ra->size - 1);
>  
> -	if (new_order < MAX_PAGECACHE_ORDER)
> +	if (new_order < mapping_max_folio_order(mapping))
>  		new_order += 2;
>  
> -	new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order);
> +	new_order = min(mapping_max_folio_order(mapping), new_order);
>  	new_order = min_t(unsigned int, new_order, ilog2(ra->size));
>  
>  	/* See comment in page_cache_ra_unbounded() */
> -- 
> 2.44.1
>
diff mbox series

Patch

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index d9c7edb6422bd..c60025bb584c5 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -204,14 +204,21 @@  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_INACCESSIBLE,	/* Do not attempt direct R/W access to the mapping,
-				   including to move the mapping */
+	AS_INACCESSIBLE = 8,	/* Do not attempt direct R/W access to the mapping */
+	/* Bits 16-25 are used for FOLIO_ORDER */
+	AS_FOLIO_ORDER_BITS = 5,
+	AS_FOLIO_ORDER_MIN = 16,
+	AS_FOLIO_ORDER_MAX = AS_FOLIO_ORDER_MIN + AS_FOLIO_ORDER_BITS,
 };
 
+#define AS_FOLIO_ORDER_BITS_MASK ((1u << AS_FOLIO_ORDER_BITS) - 1)
+#define AS_FOLIO_ORDER_MIN_MASK (AS_FOLIO_ORDER_BITS_MASK << AS_FOLIO_ORDER_MIN)
+#define AS_FOLIO_ORDER_MAX_MASK (AS_FOLIO_ORDER_BITS_MASK << AS_FOLIO_ORDER_MAX)
+#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
@@ -367,9 +374,51 @@  static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
 #define MAX_XAS_ORDER		(XA_CHUNK_SHIFT * 2 - 1)
 #define MAX_PAGECACHE_ORDER	min(MAX_XAS_ORDER, PREFERRED_MAX_PAGECACHE_ORDER)
 
+/*
+ * mapping_set_folio_order_range() - Set the orders supported by a file.
+ * @mapping: The address space of the file.
+ * @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,
+						 unsigned int max)
+{
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
+		return;
+
+	if (min > MAX_PAGECACHE_ORDER)
+		min = MAX_PAGECACHE_ORDER;
+
+	if (max > MAX_PAGECACHE_ORDER)
+		max = MAX_PAGECACHE_ORDER;
+
+	if (max < min)
+		max = min;
+
+	mapping->flags = (mapping->flags & ~AS_FOLIO_ORDER_MASK) |
+		(min << AS_FOLIO_ORDER_MIN) | (max << 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 of the file.
  *
  * The filesystem should call this function in its inode constructor to
  * indicate that the VFS can use large folios to cache the contents of
@@ -380,7 +429,23 @@  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(const struct address_space *mapping)
+{
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
+		return 0;
+	return (mapping->flags & AS_FOLIO_ORDER_MAX_MASK) >> AS_FOLIO_ORDER_MAX;
+}
+
+static inline unsigned int
+mapping_min_folio_order(const struct address_space *mapping)
+{
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
+		return 0;
+	return (mapping->flags & AS_FOLIO_ORDER_MIN_MASK) >> AS_FOLIO_ORDER_MIN;
 }
 
 /*
@@ -389,20 +454,17 @@  static inline void mapping_set_large_folios(struct address_space *mapping)
  */
 static inline bool mapping_large_folio_support(struct address_space *mapping)
 {
-	/* AS_LARGE_FOLIO_SUPPORT is only reasonable for pagecache folios */
+	/* AS_FOLIO_ORDER is only reasonable for pagecache folios */
 	VM_WARN_ONCE((unsigned long)mapping & PAGE_MAPPING_ANON,
 			"Anonymous mapping always supports large folio");
 
-	return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
-		test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
+	return mapping_max_folio_order(mapping) > 0;
 }
 
 /* Return the maximum folio size for this pagecache mapping, in bytes. */
-static inline size_t mapping_max_folio_size(struct address_space *mapping)
+static inline size_t mapping_max_folio_size(const struct address_space *mapping)
 {
-	if (mapping_large_folio_support(mapping))
-		return PAGE_SIZE << MAX_PAGECACHE_ORDER;
-	return PAGE_SIZE;
+	return PAGE_SIZE << mapping_max_folio_order(mapping);
 }
 
 static inline int filemap_nr_thps(struct address_space *mapping)
diff --git a/mm/filemap.c b/mm/filemap.c
index d87c858465962..5c148144d5548 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1932,10 +1932,8 @@  struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
 		if (WARN_ON_ONCE(!(fgp_flags & (FGP_LOCK | FGP_FOR_MMAP))))
 			fgp_flags |= FGP_LOCK;
 
-		if (!mapping_large_folio_support(mapping))
-			order = 0;
-		if (order > MAX_PAGECACHE_ORDER)
-			order = MAX_PAGECACHE_ORDER;
+		if (order > mapping_max_folio_order(mapping))
+			order = mapping_max_folio_order(mapping);
 		/* If we're not aligned, allocate a smaller folio */
 		if (index & ((1UL << order) - 1))
 			order = __ffs(index);
diff --git a/mm/readahead.c b/mm/readahead.c
index e83fe1c6e5acd..e0cf3bfd2b2b3 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -449,10 +449,10 @@  void page_cache_ra_order(struct readahead_control *ractl,
 
 	limit = min(limit, index + ra->size - 1);
 
-	if (new_order < MAX_PAGECACHE_ORDER)
+	if (new_order < mapping_max_folio_order(mapping))
 		new_order += 2;
 
-	new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order);
+	new_order = min(mapping_max_folio_order(mapping), new_order);
 	new_order = min_t(unsigned int, new_order, ilog2(ra->size));
 
 	/* See comment in page_cache_ra_unbounded() */