* [PATCH v4 0/3] mm: sparse: remove __section_nr() function
[not found] <CGME20210707150538epcas1p35450f5b6058e2ea9e06446f10d9bf662@epcas1p3.samsung.com>
@ 2021-07-07 15:02 ` Ohhoon Kwon
[not found] ` <CGME20210707150538epcas1p4b893d4fcd9eab24e4e06714efc24299e@epcas1p4.samsung.com>
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Ohhoon Kwon @ 2021-07-07 15:02 UTC (permalink / raw)
To: david, ohoono.kwon, akpm, mhocko
Cc: bhe, rppt, ohkwon1043, linux-mm, linux-kernel
This series contains cleanups to remove __section_nr().
In contrast to v1, there were some modifications on commit messages
In contrast to v2, [PATCH 1/3] has been updated to pass section_nr as
well as mem_section, as Michal suggested.
Also, I appended acked-by's and reviewed-by's from the initial mailing
list for convenience.
Ohhoon Kwon (3):
mm: sparse: pass section_nr to section_mark_present
mm: sparse: pass section_nr to find_memory_block
mm: sparse: remove __section_nr() function
.../platforms/pseries/hotplug-memory.c | 4 +--
drivers/base/memory.c | 4 +--
include/linux/memory.h | 2 +-
include/linux/mmzone.h | 1 -
mm/sparse.c | 35 +++----------------
5 files changed, 8 insertions(+), 38 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v4 1/3] mm: sparse: pass section_nr to section_mark_present
[not found] ` <CGME20210707150538epcas1p4b893d4fcd9eab24e4e06714efc24299e@epcas1p4.samsung.com>
@ 2021-07-07 15:02 ` Ohhoon Kwon
0 siblings, 0 replies; 4+ messages in thread
From: Ohhoon Kwon @ 2021-07-07 15:02 UTC (permalink / raw)
To: david, ohoono.kwon, akpm, mhocko
Cc: bhe, rppt, ohkwon1043, linux-mm, linux-kernel
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.
Since both callers of section_mark_present already know section_nr,
let's also pass section_nr as well as mem_section in order to reduce
costly translation.
Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
mm/sparse.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/mm/sparse.c b/mm/sparse.c
index 6326cdf36c4f..8018ee7fcda5 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -187,10 +187,9 @@ void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
* those loops early.
*/
unsigned long __highest_present_section_nr;
-static void section_mark_present(struct mem_section *ms)
+static void __section_mark_present(struct mem_section *ms,
+ unsigned long section_nr)
{
- unsigned long section_nr = __section_nr(ms);
-
if (section_nr > __highest_present_section_nr)
__highest_present_section_nr = section_nr;
@@ -280,7 +279,7 @@ static void __init memory_present(int nid, unsigned long start, unsigned long en
if (!ms->section_mem_map) {
ms->section_mem_map = sparse_encode_early_nid(nid) |
SECTION_IS_ONLINE;
- section_mark_present(ms);
+ __section_mark_present(ms, section);
}
}
}
@@ -934,7 +933,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
ms = __nr_to_section(section_nr);
set_section_nid(section_nr, nid);
- section_mark_present(ms);
+ __section_mark_present(ms, section_nr);
/* Align memmap to section boundary in the subsection case */
if (section_nr_to_pfn(section_nr) != start_pfn)
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v4 2/3] mm: sparse: pass section_nr to find_memory_block
[not found] ` <CGME20210707150538epcas1p2b2424d8303874d62d3ede60c38db6b59@epcas1p2.samsung.com>
@ 2021-07-07 15:02 ` Ohhoon Kwon
0 siblings, 0 replies; 4+ messages in thread
From: Ohhoon Kwon @ 2021-07-07 15:02 UTC (permalink / raw)
To: david, ohoono.kwon, akpm, mhocko
Cc: bhe, rppt, ohkwon1043, linux-mm, linux-kernel
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.
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>
---
arch/powerpc/platforms/pseries/hotplug-memory.c | 4 +---
drivers/base/memory.c | 4 ++--
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 d5ffaab3cb61..e31598955cc4 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);
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v4 3/3] mm: sparse: remove __section_nr() function
[not found] ` <CGME20210707150538epcas1p149f866bf9b4c900a091c006df7162a23@epcas1p1.samsung.com>
@ 2021-07-07 15:02 ` Ohhoon Kwon
0 siblings, 0 replies; 4+ messages in thread
From: Ohhoon Kwon @ 2021-07-07 15:02 UTC (permalink / raw)
To: david, ohoono.kwon, akpm, mhocko
Cc: bhe, rppt, ohkwon1043, linux-mm, linux-kernel
As the last users of __section_nr() are gone, let's remove unused
function __section_nr().
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>
---
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 fcb535560028..8827f4d081d4 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1342,7 +1342,6 @@ 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 8018ee7fcda5..d85655242ed9 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -109,32 +109,6 @@ 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
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[not found] <CGME20210707150538epcas1p35450f5b6058e2ea9e06446f10d9bf662@epcas1p3.samsung.com>
2021-07-07 15:02 ` [PATCH v4 0/3] mm: sparse: remove __section_nr() function Ohhoon Kwon
[not found] ` <CGME20210707150538epcas1p4b893d4fcd9eab24e4e06714efc24299e@epcas1p4.samsung.com>
2021-07-07 15:02 ` [PATCH v4 1/3] mm: sparse: pass section_nr to section_mark_present Ohhoon Kwon
[not found] ` <CGME20210707150538epcas1p2b2424d8303874d62d3ede60c38db6b59@epcas1p2.samsung.com>
2021-07-07 15:02 ` [PATCH v4 2/3] mm: sparse: pass section_nr to find_memory_block Ohhoon Kwon
[not found] ` <CGME20210707150538epcas1p149f866bf9b4c900a091c006df7162a23@epcas1p1.samsung.com>
2021-07-07 15:02 ` [PATCH v4 3/3] mm: sparse: remove __section_nr() function Ohhoon Kwon
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