2023-03-15 11:31:54

by Kirill A. Shutemov

Subject: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()

MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.

Fix MAX_ORDER usage in tsb_grow().

Signed-off-by: Kirill A. Shutemov <[email protected]>
Cc: [email protected]
Cc: David Miller <[email protected]>
---
arch/sparc/mm/tsb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
index 912205787161..dba8dffe2113 100644
--- a/arch/sparc/mm/tsb.c
+++ b/arch/sparc/mm/tsb.c
@@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
unsigned long new_rss_limit;
gfp_t gfp_flags;

- if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
- max_tsb_size = (PAGE_SIZE << MAX_ORDER);
+ if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
+ max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));

new_cache_index = 0;
for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
--
2.39.2

2023-03-16 03:05:32

by Mike Kravetz

Subject: Re: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()

On 03/15/23 14:31, Kirill A. Shutemov wrote:
> MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> can deliver is MAX_ORDER-1.
>
> Fix MAX_ORDER usage in tsb_grow().
>
> Signed-off-by: Kirill A. Shutemov <[email protected]>
> Cc: [email protected]
> Cc: David Miller <[email protected]>
> ---
> arch/sparc/mm/tsb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
> index 912205787161..dba8dffe2113 100644
> --- a/arch/sparc/mm/tsb.c
> +++ b/arch/sparc/mm/tsb.c
> @@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
> unsigned long new_rss_limit;
> gfp_t gfp_flags;
>
> - if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
> - max_tsb_size = (PAGE_SIZE << MAX_ORDER);
> + if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
> + max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
>
> new_cache_index = 0;
> for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
>

Fortunately, I think this only comes into play if MAX_ORDER <= 7.

Reviewed-by: Mike Kravetz <[email protected]>
--
Mike Kravetz

2023-03-17 08:37:24

by Mike Rapoport

Subject: Re: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()

On Wed, Mar 15, 2023 at 02:31:24PM +0300, Kirill A. Shutemov wrote:
> MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> can deliver is MAX_ORDER-1.
>
> Fix MAX_ORDER usage in tsb_grow().
>
> Signed-off-by: Kirill A. Shutemov <[email protected]>
> Cc: [email protected]
> Cc: David Miller <[email protected]>

Acked-by: Mike Rapoport (IBM) <[email protected]>

> ---
> arch/sparc/mm/tsb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
> index 912205787161..dba8dffe2113 100644
> --- a/arch/sparc/mm/tsb.c
> +++ b/arch/sparc/mm/tsb.c
> @@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
> unsigned long new_rss_limit;
> gfp_t gfp_flags;
>
> - if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
> - max_tsb_size = (PAGE_SIZE << MAX_ORDER);
> + if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
> + max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
>
> new_cache_index = 0;
> for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
> --
> 2.39.2
>

--
Sincerely yours,
Mike.

2023-03-17 08:48:02

by Mike Rapoport

Subject: Re: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()

On Wed, Mar 15, 2023 at 08:04:37PM -0700, Mike Kravetz wrote:
> On 03/15/23 14:31, Kirill A. Shutemov wrote:
> > MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> > can deliver is MAX_ORDER-1.
> >
> > Fix MAX_ORDER usage in tsb_grow().
> >
> > Signed-off-by: Kirill A. Shutemov <[email protected]>
> > Cc: [email protected]
> > Cc: David Miller <[email protected]>
> > ---
> > arch/sparc/mm/tsb.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
> > index 912205787161..dba8dffe2113 100644
> > --- a/arch/sparc/mm/tsb.c
> > +++ b/arch/sparc/mm/tsb.c
> > @@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
> > unsigned long new_rss_limit;
> > gfp_t gfp_flags;
> >
> > - if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
> > - max_tsb_size = (PAGE_SIZE << MAX_ORDER);
> > + if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
> > + max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
> >
> > new_cache_index = 0;
> > for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
> >
>
> Fortunately, I think this only comes into play if MAX_ORDER <= 7.

I think it's unlikely that such low ARCH_FORCE_MAX_ORDER is ever used.

Judging by c88c545bf320 ("sparc64: Add FORCE_MAX_ZONEORDER and default to
13") log the option to override MAX_ORDER was added to "request large (32M)
contiguous memory during boot for creating IOTSB backing store", so it was
about to increase MAX_ORDER.

Generally, we may restrict sparc::ARCH_FORCE_MAX_ORDER to be above 7 and
drop this check entirely

> Reviewed-by: Mike Kravetz <[email protected]>
> --
> Mike Kravetz
>

--
Sincerely yours,
Mike.

2023-03-21 07:48:55

by Vlastimil Babka

Subject: Re: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()

On 3/15/23 12:31, Kirill A. Shutemov wrote:
> MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> can deliver is MAX_ORDER-1.
>
> Fix MAX_ORDER usage in tsb_grow().
>
> Signed-off-by: Kirill A. Shutemov <[email protected]>

Acked-by: Vlastimil Babka <[email protected]>

> Cc: [email protected]
> Cc: David Miller <[email protected]>
> ---
> arch/sparc/mm/tsb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
> index 912205787161..dba8dffe2113 100644
> --- a/arch/sparc/mm/tsb.c
> +++ b/arch/sparc/mm/tsb.c
> @@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
> unsigned long new_rss_limit;
> gfp_t gfp_flags;
>
> - if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
> - max_tsb_size = (PAGE_SIZE << MAX_ORDER);
> + if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
> + max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
>
> new_cache_index = 0;
> for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {