| Message ID | 20230710160842.56300-4-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for DAX vmemmap optimization for ppc64 | expand |
Le 10/07/2023 à 18:08, Aneesh Kumar K.V a écrit : > dax vmemmap optimization requires a minimum of 2 PAGE_SIZE area within > vmemmap such that tail page mapping can point to the second PAGE_SIZE area. > Enforce that in vmemmap_can_optimize() function. > > Architectures like powerpc also want to enable vmemmap optimization > conditionally (only with radix MMU translation). Hence allow architecture > override. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Why renaming vmemmap_can_optimize() to __vmemmap_can_optimize() and keep it when vmemmap_can_optimize() has been override ? Is that because you expect overriding version of vmemmap_can_optimize() to call __vmemmap_can_optimize() ? > --- > include/linux/mm.h | 27 +++++++++++++++++++++++---- > mm/mm_init.c | 2 +- > 2 files changed, 24 insertions(+), 5 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 2dd73e4f3d8e..1a2234ee14d2 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3639,13 +3639,32 @@ void vmemmap_free(unsigned long start, unsigned long end, > struct vmem_altmap *altmap); > #endif > > +#define VMEMMAP_RESERVE_NR 2 > #ifdef CONFIG_ARCH_WANT_OPTIMIZE_VMEMMAP > -static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, > - struct dev_pagemap *pgmap) > +static inline bool __vmemmap_can_optimize(struct vmem_altmap *altmap, > + struct dev_pagemap *pgmap) > { > - return is_power_of_2(sizeof(struct page)) && > - pgmap && (pgmap_vmemmap_nr(pgmap) > 1) && !altmap; > + unsigned long nr_pages; > + unsigned long nr_vmemmap_pages; > + > + if (!pgmap || !is_power_of_2(sizeof(struct page))) > + return false; > + > + nr_pages = pgmap_vmemmap_nr(pgmap); > + nr_vmemmap_pages = ((nr_pages * sizeof(struct page)) >> PAGE_SHIFT); > + /* > + * For vmemmap optimization with DAX we need minimum 2 vmemmap > + * pages. See layout diagram in Documentation/mm/vmemmap_dedup.rst > + */ > + return !altmap && (nr_vmemmap_pages > VMEMMAP_RESERVE_NR); > } > +/* > + * If we don't have an architecture override, use the generic rule > + */ > +#ifndef vmemmap_can_optimize > +#define vmemmap_can_optimize __vmemmap_can_optimize > +#endif > + > #else > static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, > struct dev_pagemap *pgmap) > diff --git a/mm/mm_init.c b/mm/mm_init.c > index a1963c3322af..245ac69b66a5 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -1020,7 +1020,7 @@ static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, > if (!vmemmap_can_optimize(altmap, pgmap)) > return pgmap_vmemmap_nr(pgmap); > > - return 2 * (PAGE_SIZE / sizeof(struct page)); > + return VMEMMAP_RESERVE_NR * (PAGE_SIZE / sizeof(struct page)); > } > > static void __ref memmap_init_compound(struct page *head,
Christophe Leroy <christophe.leroy@csgroup.eu> writes: > Le 10/07/2023 à 18:08, Aneesh Kumar K.V a écrit : >> dax vmemmap optimization requires a minimum of 2 PAGE_SIZE area within >> vmemmap such that tail page mapping can point to the second PAGE_SIZE area. >> Enforce that in vmemmap_can_optimize() function. >> >> Architectures like powerpc also want to enable vmemmap optimization >> conditionally (only with radix MMU translation). Hence allow architecture >> override. >> >> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > > Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> > > Why renaming vmemmap_can_optimize() to __vmemmap_can_optimize() and keep > it when vmemmap_can_optimize() has been override ? Is that because you > expect overriding version of vmemmap_can_optimize() to call > __vmemmap_can_optimize() ? > Yes, __vmemap_can_optimize will be used in patch 11 https://lore.kernel.org/linuxppc-dev/20230710160842.56300-12-aneesh.kumar@linux.ibm.com -aneesh
diff --git a/include/linux/mm.h b/include/linux/mm.h index 2dd73e4f3d8e..1a2234ee14d2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3639,13 +3639,32 @@ void vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap); #endif +#define VMEMMAP_RESERVE_NR 2 #ifdef CONFIG_ARCH_WANT_OPTIMIZE_VMEMMAP -static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, - struct dev_pagemap *pgmap) +static inline bool __vmemmap_can_optimize(struct vmem_altmap *altmap, + struct dev_pagemap *pgmap) { - return is_power_of_2(sizeof(struct page)) && - pgmap && (pgmap_vmemmap_nr(pgmap) > 1) && !altmap; + unsigned long nr_pages; + unsigned long nr_vmemmap_pages; + + if (!pgmap || !is_power_of_2(sizeof(struct page))) + return false; + + nr_pages = pgmap_vmemmap_nr(pgmap); + nr_vmemmap_pages = ((nr_pages * sizeof(struct page)) >> PAGE_SHIFT); + /* + * For vmemmap optimization with DAX we need minimum 2 vmemmap + * pages. See layout diagram in Documentation/mm/vmemmap_dedup.rst + */ + return !altmap && (nr_vmemmap_pages > VMEMMAP_RESERVE_NR); } +/* + * If we don't have an architecture override, use the generic rule + */ +#ifndef vmemmap_can_optimize +#define vmemmap_can_optimize __vmemmap_can_optimize +#endif + #else static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, struct dev_pagemap *pgmap) diff --git a/mm/mm_init.c b/mm/mm_init.c index a1963c3322af..245ac69b66a5 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1020,7 +1020,7 @@ static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, if (!vmemmap_can_optimize(altmap, pgmap)) return pgmap_vmemmap_nr(pgmap); - return 2 * (PAGE_SIZE / sizeof(struct page)); + return VMEMMAP_RESERVE_NR * (PAGE_SIZE / sizeof(struct page)); } static void __ref memmap_init_compound(struct page *head,
dax vmemmap optimization requires a minimum of 2 PAGE_SIZE area within vmemmap such that tail page mapping can point to the second PAGE_SIZE area. Enforce that in vmemmap_can_optimize() function. Architectures like powerpc also want to enable vmemmap optimization conditionally (only with radix MMU translation). Hence allow architecture override. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- include/linux/mm.h | 27 +++++++++++++++++++++++---- mm/mm_init.c | 2 +- 2 files changed, 24 insertions(+), 5 deletions(-)