[PATCH v1 4/6] mm/memory_hotplug: Rename walk_memory_range() and pass start+size instead of pfns

David Hildenbrand
2019-06-14T10:02:05Z

walk_memory_range() was once used to iterate over sections. Now, it
iterates over memory blocks. Rename the function, fixup the
documentation. Also, pass start+size instead of PFNs, which is what most
callers already have at hand. (we'll rework link_mem_sections() most
probably soon)

Follow-up patches wil rework, simplify, and move walk_memory_blocks() to
drivers/base/memory.c.

Note: walk_memory_blocks() only works correctly right now if the
start_pfn is aligned to a section start. This is the case right now,
but we'll generalize the function in a follow up patch so the semantics
match the documentation.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Arun KS <arunks@codeaurora.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/powernv/memtrace.c | 22 ++++++++++-----------
drivers/acpi/acpi_memhotplug.c | 19 ++++--------------
drivers/base/node.c | 5 +++--
include/linux/memory_hotplug.h | 2 +-
mm/memory_hotplug.c | 24 ++++++++++++-----------
5 files changed, 32 insertions(+), 40 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 5e53c1392d3b..8c82c041afe6 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -70,23 +70,24 @@ static int change_memblock_state(struct memory_block *mem, void *arg)
/* called with device_hotplug_lock held */
static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
{
+ const unsigned long start = PFN_PHYS(start_pfn);
+ const unsigned long size = PFN_PHYS(nr_pages);
u64 end_pfn = start_pfn + nr_pages - 1;

- if (walk_memory_range(start_pfn, end_pfn, NULL,
- check_memblock_online))
+ if (walk_memory_blocks(start, size, NULL, check_memblock_online))
return false;

- walk_memory_range(start_pfn, end_pfn, (void *)MEM_GOING_OFFLINE,
- change_memblock_state);
+ walk_memory_blocks(start, size, (void *)MEM_GOING_OFFLINE,
+ change_memblock_state);

if (offline_pages(start_pfn, nr_pages)) {
- walk_memory_range(start_pfn, end_pfn, (void *)MEM_ONLINE,
- change_memblock_state);
+ walk_memory_blocks(start, size, (void *)MEM_ONLINE,
+ change_memblock_state);
return false;
}

- walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE,
- change_memblock_state);
+ walk_memory_blocks(start, size, (void *)MEM_OFFLINE,
+ change_memblock_state);

return true;
@@ -242,9 +243,8 @@ static int memtrace_online(void)
*/
if (!memhp_auto_online) {
lock_device_hotplug();
- walk_memory_range(PFN_DOWN(ent->start),
- PFN_UP(ent->start + ent->size - 1),
- NULL, online_mem_block);
+ walk_memory_blocks(ent->start, ent->size, NULL,
+ online_mem_block);
unlock_device_hotplug();
}

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index db013dc21c02..e294f44a7850 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -155,16 +155,6 @@ static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
return 0;
}

-static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
-{
- return PFN_DOWN(info->start_addr);
-}
-
-static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
-{
- return PFN_UP(info->start_addr + info->length-1);
-}
-
static int acpi_bind_memblk(struct memory_block *mem, void *arg)
{
return acpi_bind_one(&mem->dev, arg);
@@ -173,9 +163,8 @@ static int acpi_bind_memblk(struct memory_block *mem, void *arg)
static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
struct acpi_device *adev)
{
- return walk_memory_range(acpi_meminfo_start_pfn(info),
- acpi_meminfo_end_pfn(info), adev,
- acpi_bind_memblk);
+ return walk_memory_blocks(info->start_addr, info->length, adev,
+ acpi_bind_memblk);
}

static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
@@ -186,8 +175,8 @@ static int acpi_unbind_memblk(struct memory_block *mem, void *arg)

static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
{
- walk_memory_range(acpi_meminfo_start_pfn(info),
- acpi_meminfo_end_pfn(info), NULL, acpi_unbind_memblk);
+ walk_memory_blocks(info->start_addr, info->length, NULL,
+ acpi_unbind_memblk);
}

static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
diff --git a/drivers/base/node.c b/drivers/base/node.c
index e6364e3e3e31..d8c02e65df68 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -833,8 +833,9 @@ void unregister_memory_block_under_nodes(struct memory_block *mem_blk)

int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn)
{
- return walk_memory_range(start_pfn, end_pfn, (void *)&nid,
- register_mem_sect_under_node);
+ return walk_memory_blocks(PFN_PHYS(start_pfn),
+ PFN_PHYS(end_pfn - start_pfn), (void *)&nid,
+ register_mem_sect_under_node);
}

#ifdef CONFIG_HUGETLBFS
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 79e0add6a597..d9fffc34949f 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -340,7 +340,7 @@ static inline void __remove_memory(int nid, u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */

extern void __ref free_area_init_core_hotplug(int nid);
-extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
+extern int walk_memory_blocks(unsigned long start, unsigned long size,
void *arg, int (*func)(struct memory_block *, void *));
extern int __add_memory(int nid, u64 start, u64 size);
extern int add_memory(int nid, u64 start, u64 size);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a88c5f334e5a..122a7d31efdd 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1126,8 +1126,7 @@ int __ref add_memory_resource(int nid, struct resource *res)

/* online pages if requested */
if (memhp_auto_online)
- walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
- NULL, online_memory_block);
+ walk_memory_blocks(start, size, NULL, online_memory_block);

return ret;
error:
@@ -1665,20 +1664,24 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
#endif /* CONFIG_MEMORY_HOTREMOVE */

/**
- * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
- * @start_pfn: start pfn of the memory range
- * @end_pfn: end pfn of the memory range
+ * walk_memory_blocks - walk through all present memory blocks overlapped
+ * by the range [start, start + size)
+ *
+ * @start: start address of the memory range
+ * @size: size of the memory range
* @arg: argument passed to func
- * @func: callback for each memory section walked
+ * @func: callback for each memory block walked
*
- * This function walks through all present mem sections in range
- * [start_pfn, end_pfn) and call func on each mem section.
+ * This function walks through all present memory blocks overlapped by the
+ * range [start, start + size), calling func on each memory block.
*
* Returns the return value of func.
*/
-int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
+int walk_memory_blocks(unsigned long start, unsigned long size,
void *arg, int (*func)(struct memory_block *, void *))
{
+ const unsigned long start_pfn = PFN_DOWN(start);
+ const unsigned long end_pfn = PFN_UP(start + size - 1);
struct memory_block *mem = NULL;
struct mem_section *section;
unsigned long pfn, section_nr;
@@ -1824,8 +1827,7 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size)
* whether all memory blocks in question are offline and return error
* if this is not the case.
*/
- rc = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
- check_memblock_offlined_cb);
+ rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
if (rc)
goto done;

--
2.21.0