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| author | Ohhoon Kwon <ohoono.kwon@samsung.com> | 2021-09-02 14:57:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-03 09:58:14 -0700 |
| commit | fc1f5e980a463325cf41d39ac6a69aa3cca73995 (patch) | |
| tree | 79507c488549d1a0c253e3d2b67d9fb24c093637 | |
| parent | a1bc561bb2d3d9b944878955095f53aeba30a166 (diff) | |
| download | linux-fc1f5e980a463325cf41d39ac6a69aa3cca73995.tar.gz linux-fc1f5e980a463325cf41d39ac6a69aa3cca73995.tar.bz2 linux-fc1f5e980a463325cf41d39ac6a69aa3cca73995.zip | |
mm: sparse: pass section_nr to find_memory_block
With CONFIG_SPARSEMEM_EXTREME enabled, __section_nr() which converts
mem_section to section_nr could 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).
Let's pass section_nr instead of mem_section ptr to find_memory_block() in
order to reduce needless iterations.
Link: https://lkml.kernel.org/r/20210707150212.855-3-ohoono.kwon@samsung.com
Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/powerpc/platforms/pseries/hotplug-memory.c | 4 | ||||
| -rw-r--r-- | drivers/base/memory.c | 4 | ||||
| -rw-r--r-- | include/linux/memory.h | 2 |
3 files changed, 4 insertions, 6 deletions
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index 377d852f5a9a..d4f28ee4d5dc 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -211,13 +211,11 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb) static struct memory_block *lmb_to_memblock(struct drmem_lmb *lmb) { unsigned long section_nr; - struct mem_section *mem_sect; struct memory_block *mem_block; section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr)); - mem_sect = __nr_to_section(section_nr); - mem_block = find_memory_block(mem_sect); + mem_block = find_memory_block(section_nr); return mem_block; } diff --git a/drivers/base/memory.c b/drivers/base/memory.c index aa31a21f33d7..e3fd2dbf4eea 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -578,9 +578,9 @@ static struct memory_block *find_memory_block_by_id(unsigned long block_id) /* * Called under device_hotplug_lock. */ -struct memory_block *find_memory_block(struct mem_section *section) +struct memory_block *find_memory_block(unsigned long section_nr) { - unsigned long block_id = memory_block_id(__section_nr(section)); + unsigned long block_id = memory_block_id(section_nr); return find_memory_block_by_id(block_id); } diff --git a/include/linux/memory.h b/include/linux/memory.h index 97e92e8b556a..d9a0b61cd432 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -90,7 +90,7 @@ int create_memory_block_devices(unsigned long start, unsigned long size, void remove_memory_block_devices(unsigned long start, unsigned long size); extern void memory_dev_init(void); extern int memory_notify(unsigned long val, void *v); -extern struct memory_block *find_memory_block(struct mem_section *); +extern struct memory_block *find_memory_block(unsigned long section_nr); typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *); extern int walk_memory_blocks(unsigned long start, unsigned long size, void *arg, walk_memory_blocks_func_t func); |