diff mbox series

[RFC,02/23] pagemap: use mapping_min_order in fgf_set_order()

Message ID 20230915183848.1018717-3-kernel@pankajraghav.com
State New
Headers
Series Enable block size > page size in XFS |

Commit Message

Pankaj Raghav (Samsung) Sept. 15, 2023, 6:38 p.m. UTC 
  From: Pankaj Raghav <p.raghav@samsung.com>

fgf_set_order() encodes optimal order in fgp flags. Set it to at least
mapping_min_order from the page cache. Default to the old behaviour if
min_order is not set.

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/iomap/buffered-io.c  | 2 +-
 include/linux/pagemap.h | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

Comments

Matthew Wilcox Sept. 15, 2023, 6:55 p.m. UTC | #1 
On Fri, Sep 15, 2023 at 08:38:27PM +0200, Pankaj Raghav wrote:
> From: Pankaj Raghav <p.raghav@samsung.com>
> 
> fgf_set_order() encodes optimal order in fgp flags. Set it to at least
> mapping_min_order from the page cache. Default to the old behaviour if
> min_order is not set.

Why not simply:

+++ b/mm/filemap.c
@@ -1906,9 +1906,12 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
                folio_wait_stable(folio);
 no_page:
        if (!folio && (fgp_flags & FGP_CREAT)) {
-               unsigned order = FGF_GET_ORDER(fgp_flags);
+               unsigned order;
                int err;

+               order = min(mapping_min_folio_order(mapping),
+                               FGF_GET_ORDER(fgp_flags));
Pankaj Raghav Sept. 20, 2023, 7:46 a.m. UTC | #2 
On 2023-09-15 20:55, Matthew Wilcox wrote:
> On Fri, Sep 15, 2023 at 08:38:27PM +0200, Pankaj Raghav wrote:
>> From: Pankaj Raghav <p.raghav@samsung.com>
>>
>> fgf_set_order() encodes optimal order in fgp flags. Set it to at least
>> mapping_min_order from the page cache. Default to the old behaviour if
>> min_order is not set.
> 
> Why not simply:
> 

That is a good idea to move this to filemap instead of changing it in iomap. I will do that!

> +++ b/mm/filemap.c
> @@ -1906,9 +1906,12 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
>                 folio_wait_stable(folio);
>  no_page:
>         if (!folio && (fgp_flags & FGP_CREAT)) {
> -               unsigned order = FGF_GET_ORDER(fgp_flags);
> +               unsigned order;
>                 int err;
> 
> +               order = min(mapping_min_folio_order(mapping),
> +                               FGF_GET_ORDER(fgp_flags));
> 

I think this needs to max(mapping..., FGF...)
diff mbox series

Patch

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index ae8673ce08b1..d4613fd550c4 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -549,7 +549,7 @@  struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len)
 
 	if (iter->flags & IOMAP_NOWAIT)
 		fgp |= FGP_NOWAIT;
-	fgp |= fgf_set_order(len);
+	fgp |= fgf_set_order(iter->inode->i_mapping, len);
 
 	return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
 			fgp, mapping_gfp_mask(iter->inode->i_mapping));
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index d2b5308cc59e..5d392366420a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -620,6 +620,7 @@  typedef unsigned int __bitwise fgf_t;
 
 /**
  * fgf_set_order - Encode a length in the fgf_t flags.
+ * @mapping: address_space struct from the inode
  * @size: The suggested size of the folio to create.
  *
  * The caller of __filemap_get_folio() can use this to suggest a preferred
@@ -629,13 +630,13 @@  typedef unsigned int __bitwise fgf_t;
  * due to alignment constraints, memory pressure, or the presence of
  * other folios at nearby indices.
  */
-static inline fgf_t fgf_set_order(size_t size)
+static inline fgf_t fgf_set_order(struct address_space *mapping, size_t size)
 {
 	unsigned int shift = ilog2(size);
+	unsigned int min_order = mapping_min_folio_order(mapping);
+	int order = max(min_order, shift - PAGE_SHIFT);
 
-	if (shift <= PAGE_SHIFT)
-		return 0;
-	return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
+	return (__force fgf_t)((order) << 26);
 }
 
 void *filemap_get_entry(struct address_space *mapping, pgoff_t index);