| Message ID | 20230315113133.11326-2-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix confusion around MAX_ORDER | expand |
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 <kirill.shutemov@linux.intel.com> > Cc: sparclinux@vger.kernel.org > Cc: David Miller <davem@davemloft.net> > --- > 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 <mike.kravetz@oracle.com>
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 <kirill.shutemov@linux.intel.com> > Cc: sparclinux@vger.kernel.org > Cc: David Miller <davem@davemloft.net> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> > --- > 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 >
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 <kirill.shutemov@linux.intel.com> > > Cc: sparclinux@vger.kernel.org > > Cc: David Miller <davem@davemloft.net> > > --- > > 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 <mike.kravetz@oracle.com> > -- > Mike Kravetz >
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 <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > Cc: sparclinux@vger.kernel.org > Cc: David Miller <davem@davemloft.net> > --- > 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) {
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) {
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 <kirill.shutemov@linux.intel.com> Cc: sparclinux@vger.kernel.org Cc: David Miller <davem@davemloft.net> --- arch/sparc/mm/tsb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)