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* [PATCH] Fix khugepaged's request size in collapse_file()
@ 2020-09-02 14:16 David Howells
  2020-09-02 17:43 ` Yang Shi
  2020-09-02 18:54 ` Pankaj Gupta
  0 siblings, 2 replies; 3+ messages in thread
From: David Howells @ 2020-09-02 14:16 UTC (permalink / raw)
  To: akpm; +Cc: Song Liu, Matthew Wilcox (Oracle), dhowells, linux-mm, linux-kernel

collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to be
read ahead to page_cache_sync_readahead().  It seems this was expressed as a
number of bytes rather than a number of pages.

Fix it to use the number of pages to the end of the window instead.

Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---

 mm/khugepaged.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 6d199c353281..f2d243077b74 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1706,7 +1706,7 @@ static void collapse_file(struct mm_struct *mm,
 				xas_unlock_irq(&xas);
 				page_cache_sync_readahead(mapping, &file->f_ra,
 							  file, index,
-							  PAGE_SIZE);
+							  end - index);
 				/* drain pagevecs to help isolate_lru_page() */
 				lru_add_drain();
 				page = find_lock_page(mapping, index);




^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] Fix khugepaged's request size in collapse_file()
  2020-09-02 14:16 [PATCH] Fix khugepaged's request size in collapse_file() David Howells
@ 2020-09-02 17:43 ` Yang Shi
  2020-09-02 18:54 ` Pankaj Gupta
  1 sibling, 0 replies; 3+ messages in thread
From: Yang Shi @ 2020-09-02 17:43 UTC (permalink / raw)
  To: David Howells
  Cc: Andrew Morton, Song Liu, Matthew Wilcox (Oracle),
	Linux MM, Linux Kernel Mailing List

On Wed, Sep 2, 2020 at 7:16 AM David Howells <dhowells@redhat.com> wrote:
>
> collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to be
> read ahead to page_cache_sync_readahead().  It seems this was expressed as a
> number of bytes rather than a number of pages.
>
> Fix it to use the number of pages to the end of the window instead.
>
> Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
> Signed-off-by: David Howells <dhowells@redhat.com>
> Acked-by: Song Liu <songliubraving@fb.com>
> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Acked-by: Yang Shi <shy828301@gmail.com>

> ---
>
>  mm/khugepaged.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 6d199c353281..f2d243077b74 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -1706,7 +1706,7 @@ static void collapse_file(struct mm_struct *mm,
>                                 xas_unlock_irq(&xas);
>                                 page_cache_sync_readahead(mapping, &file->f_ra,
>                                                           file, index,
> -                                                         PAGE_SIZE);
> +                                                         end - index);
>                                 /* drain pagevecs to help isolate_lru_page() */
>                                 lru_add_drain();
>                                 page = find_lock_page(mapping, index);
>
>
>


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] Fix khugepaged's request size in collapse_file()
  2020-09-02 14:16 [PATCH] Fix khugepaged's request size in collapse_file() David Howells
  2020-09-02 17:43 ` Yang Shi
@ 2020-09-02 18:54 ` Pankaj Gupta
  1 sibling, 0 replies; 3+ messages in thread
From: Pankaj Gupta @ 2020-09-02 18:54 UTC (permalink / raw)
  To: David Howells
  Cc: Andrew Morton, Song Liu, Matthew Wilcox (Oracle), Linux MM, LKML

> collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to be
> read ahead to page_cache_sync_readahead().  It seems this was expressed as a
> number of bytes rather than a number of pages.
>
> Fix it to use the number of pages to the end of the window instead.
>
> Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
> Signed-off-by: David Howells <dhowells@redhat.com>
> Acked-by: Song Liu <songliubraving@fb.com>
> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>
>  mm/khugepaged.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 6d199c353281..f2d243077b74 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -1706,7 +1706,7 @@ static void collapse_file(struct mm_struct *mm,
>                                 xas_unlock_irq(&xas);
>                                 page_cache_sync_readahead(mapping, &file->f_ra,
>                                                           file, index,
> -                                                         PAGE_SIZE);
> +                                                         end - index);
>                                 /* drain pagevecs to help isolate_lru_page() */
>                                 lru_add_drain();
>                                 page = find_lock_page(mapping, index);
>

Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2020-09-02 18:54 UTC | newest]

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2020-09-02 14:16 [PATCH] Fix khugepaged's request size in collapse_file() David Howells
2020-09-02 17:43 ` Yang Shi
2020-09-02 18:54 ` Pankaj Gupta

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