| Message ID | 20210702094132.6276-4-ohoono.kwon@samsung.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: sparse: remove __section_nr() function | expand |
On Fri 02-07-21 18:41:32, Ohhoon Kwon wrote: > __section_nr() was used to convert struct mem_section * to section_nr. > > With CONFIG_SPARSEMEM_EXTREME enabled, however, __section_nr() can be > costly since it iterates all section roots to check if the given > mem_section is in its range. > > On the other hand, __nr_to_section() which converts section_nr to > mem_section can be done in O(1). > > The only users of __section_nr() was section_mark_present() and > find_memory_block(). > > Since I changed both functions to use section_nr directly in the > preceeding patches, let's remove __section_nr() which has no users. > > Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com> I would go with a much shorter changelog. The function is not used anymore so it can be simply dropped. Acked-by: Michal Hocko <mhocko@suse.com> > --- > include/linux/mmzone.h | 1 - > mm/sparse.c | 26 -------------------------- > 2 files changed, 27 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 0d53eba1c383..8931f95cf885 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1321,7 +1321,6 @@ static inline struct mem_section *__nr_to_section(unsigned long nr) > return NULL; > return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; > } > -extern unsigned long __section_nr(struct mem_section *ms); > extern size_t mem_section_usage_size(void); > > /* > diff --git a/mm/sparse.c b/mm/sparse.c > index 4a2700e9a65f..1b32d15593e4 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -108,32 +108,6 @@ static inline int sparse_index_init(unsigned long section_nr, int nid) > } > #endif > > -#ifdef CONFIG_SPARSEMEM_EXTREME > -unsigned long __section_nr(struct mem_section *ms) > -{ > - unsigned long root_nr; > - struct mem_section *root = NULL; > - > - for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { > - root = __nr_to_section(root_nr * SECTIONS_PER_ROOT); > - if (!root) > - continue; > - > - if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT))) > - break; > - } > - > - VM_BUG_ON(!root); > - > - return (root_nr * SECTIONS_PER_ROOT) + (ms - root); > -} > -#else > -unsigned long __section_nr(struct mem_section *ms) > -{ > - return (unsigned long)(ms - mem_section[0]); > -} > -#endif > - > /* > * During early boot, before section_mem_map is used for an actual > * mem_map, we use section_mem_map to store the section's NUMA > -- > 2.17.1
On 02.07.21 14:18, Michal Hocko wrote: > On Fri 02-07-21 18:41:32, Ohhoon Kwon wrote: >> __section_nr() was used to convert struct mem_section * to section_nr. >> >> With CONFIG_SPARSEMEM_EXTREME enabled, however, __section_nr() can be >> costly since it iterates all section roots to check if the given >> mem_section is in its range. >> >> On the other hand, __nr_to_section() which converts section_nr to >> mem_section can be done in O(1). >> >> The only users of __section_nr() was section_mark_present() and >> find_memory_block(). >> >> Since I changed both functions to use section_nr directly in the >> preceeding patches, let's remove __section_nr() which has no users. >> >> Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com> > > I would go with a much shorter changelog. The function is not used > anymore so it can be simply dropped. > Acked-by: Michal Hocko <mhocko@suse.com> Agreed, also avoid the use of "I" in patches. Use something like "As the last users of __section_nr() are gone, let's remove now unused __section_nr()." Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 0d53eba1c383..8931f95cf885 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1321,7 +1321,6 @@ static inline struct mem_section *__nr_to_section(unsigned long nr) return NULL; return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; } -extern unsigned long __section_nr(struct mem_section *ms); extern size_t mem_section_usage_size(void); /* diff --git a/mm/sparse.c b/mm/sparse.c index 4a2700e9a65f..1b32d15593e4 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -108,32 +108,6 @@ static inline int sparse_index_init(unsigned long section_nr, int nid) } #endif -#ifdef CONFIG_SPARSEMEM_EXTREME -unsigned long __section_nr(struct mem_section *ms) -{ - unsigned long root_nr; - struct mem_section *root = NULL; - - for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { - root = __nr_to_section(root_nr * SECTIONS_PER_ROOT); - if (!root) - continue; - - if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT))) - break; - } - - VM_BUG_ON(!root); - - return (root_nr * SECTIONS_PER_ROOT) + (ms - root); -} -#else -unsigned long __section_nr(struct mem_section *ms) -{ - return (unsigned long)(ms - mem_section[0]); -} -#endif - /* * During early boot, before section_mem_map is used for an actual * mem_map, we use section_mem_map to store the section's NUMA
__section_nr() was used to convert struct mem_section * to section_nr. With CONFIG_SPARSEMEM_EXTREME enabled, however, __section_nr() can be costly since it iterates all section roots to check if the given mem_section is in its range. On the other hand, __nr_to_section() which converts section_nr to mem_section can be done in O(1). The only users of __section_nr() was section_mark_present() and find_memory_block(). Since I changed both functions to use section_nr directly in the preceeding patches, let's remove __section_nr() which has no users. Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com> --- include/linux/mmzone.h | 1 - mm/sparse.c | 26 -------------------------- 2 files changed, 27 deletions(-)