2021-04-20 00:30:34

by Jane Chu

Subject: [PATCH] mm/memory-failure: unecessary amount of unmapping

It appears that unmap_mapping_range() actually takes a 'size' as its
third argument rather than a location, the current calling fashion
causes unecessary amount of unmapping to occur.

Fixes: 6100e34b2526e ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
Signed-off-by: Jane Chu <[email protected]>
---
mm/memory-failure.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index f7ed9559d494..85ad98c00fd9 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1368,7 +1368,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
* communicated in siginfo, see kill_proc()
*/
start = (page->index << PAGE_SHIFT) & ~(size - 1);
- unmap_mapping_range(page->mapping, start, start + size, 0);
+ unmap_mapping_range(page->mapping, start, size, 0);
}
kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
rc = 0;
--
2.18.4

2021-04-20 00:34:27

by Dan Williams

Subject: Re: [PATCH] mm/memory-failure: unecessary amount of unmapping

On Mon, Apr 19, 2021 at 5:28 PM Jane Chu <[email protected]> wrote:
>
> It appears that unmap_mapping_range() actually takes a 'size' as its
> third argument rather than a location,

Indeed.

> the current calling fashion
> causes unecessary amount of unmapping to occur.

s/unecessary/unnecessary/

>
> Fixes: 6100e34b2526e ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
> Signed-off-by: Jane Chu <[email protected]>

Other than changelog fixup, looks good.

Reviewed-by: Dan Williams <[email protected]>

> ---
> mm/memory-failure.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index f7ed9559d494..85ad98c00fd9 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1368,7 +1368,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
> * communicated in siginfo, see kill_proc()
> */
> start = (page->index << PAGE_SHIFT) & ~(size - 1);
> - unmap_mapping_range(page->mapping, start, start + size, 0);
> + unmap_mapping_range(page->mapping, start, size, 0);
> }
> kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
> rc = 0;
> --
> 2.18.4
>

2021-04-20 00:52:17

by HORIGUCHI NAOYA(堀口　直也)

Subject: Re: [PATCH] mm/memory-failure: unecessary amount of unmapping

On Mon, Apr 19, 2021 at 06:28:21PM -0600, Jane Chu wrote:
> It appears that unmap_mapping_range() actually takes a 'size' as its
> third argument rather than a location, the current calling fashion
> causes unecessary amount of unmapping to occur.
>
> Fixes: 6100e34b2526e ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
> Signed-off-by: Jane Chu <[email protected]>

Thanks,

Reviewed-by: Naoya Horiguchi <[email protected]>