The patch titled
Subject: mm/memory_hotplug: don't read nid from struct page during hotplug
has been added to the -mm tree. Its filename is
mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug.patch
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------------------------------------------------------
From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Subject: mm/memory_hotplug: don't read nid from struct page during hotplug
During memory hotplugging the probe routine will leave struct pages
uninitialized, the same as it is currently done during boot. Therefore,
we do not want to access the inside of struct pages before
__init_single_page() is called during onlining.
Because during hotplug we know that pages in one memory block belong to
the same numa node, we can skip the checking. We should keep checking for
the boot case.
Link: http://lkml.kernel.org/r/20180215165920.8570-6-pasha.tatashin@xxxxxxxxxx
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Steven Sistare <steven.sistare@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/memory.c | 2 +-
drivers/base/node.c | 22 +++++++++++++++-------
include/linux/node.h | 4 ++--
3 files changed, 18 insertions(+), 10 deletions(-)
diff -puN drivers/base/memory.c~mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug drivers/base/memory.c
--- a/drivers/base/memory.c~mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug
+++ a/drivers/base/memory.c
@@ -731,7 +731,7 @@ int register_new_memory(int nid, struct
}
if (mem->section_count == sections_per_block)
- ret = register_mem_sect_under_node(mem, nid);
+ ret = register_mem_sect_under_node(mem, nid, false);
out:
mutex_unlock(&mem_sysfs_mutex);
return ret;
diff -puN drivers/base/node.c~mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug drivers/base/node.c
--- a/drivers/base/node.c~mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug
+++ a/drivers/base/node.c
@@ -397,7 +397,8 @@ static int __ref get_nid_for_pfn(unsigne
}
/* register memory section under specified node if it spans that node */
-int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
+int register_mem_sect_under_node(struct memory_block *mem_blk, int nid,
+ bool check_nid)
{
int ret;
unsigned long pfn, sect_start_pfn, sect_end_pfn;
@@ -423,11 +424,18 @@ int register_mem_sect_under_node(struct
continue;
}
- page_nid = get_nid_for_pfn(pfn);
- if (page_nid < 0)
- continue;
- if (page_nid != nid)
- continue;
+ /*
+ * We need to check if page belongs to nid only for the boot
+ * case, during hotplug we know that all pages in the memory
+ * block belong to the same node.
+ */
+ if (check_nid) {
+ page_nid = get_nid_for_pfn(pfn);
+ if (page_nid < 0)
+ continue;
+ if (page_nid != nid)
+ continue;
+ }
ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
&mem_blk->dev.kobj,
kobject_name(&mem_blk->dev.kobj));
@@ -502,7 +510,7 @@ int link_mem_sections(int nid, unsigned
mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
- ret = register_mem_sect_under_node(mem_blk, nid);
+ ret = register_mem_sect_under_node(mem_blk, nid, true);
if (!err)
err = ret;
diff -puN include/linux/node.h~mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug include/linux/node.h
--- a/include/linux/node.h~mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug
+++ a/include/linux/node.h
@@ -67,7 +67,7 @@ extern void unregister_one_node(int nid)
extern int register_cpu_under_node(unsigned int cpu, unsigned int nid);
extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid);
extern int register_mem_sect_under_node(struct memory_block *mem_blk,
- int nid);
+ int nid, bool check_nid);
extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
unsigned long phys_index);
@@ -97,7 +97,7 @@ static inline int unregister_cpu_under_n
return 0;
}
static inline int register_mem_sect_under_node(struct memory_block *mem_blk,
- int nid)
+ int nid, bool check_nid)
{
return 0;
}
_
Patches currently in -mm which might be from pasha.tatashin@xxxxxxxxxx are
mm-initialize-pages-on-demand-during-boot.patch
mm-initialize-pages-on-demand-during-boot-fix-3.patch
mm-memory_hotplug-enforce-block-size-aligned-range-check.patch
x86-mm-memory_hotplug-determine-block-size-based-on-the-end-of-boot-memory.patch
x86-mm-memory_hotplug-determine-block-size-based-on-the-end-of-boot-memory-v4.patch
mm-uninitialized-struct-page-poisoning-sanity-checking.patch
mm-uninitialized-struct-page-poisoning-sanity-checking-v4.patch
mm-memory_hotplug-optimize-probe-routine.patch
mm-memory_hotplug-dont-read-nid-from-struct-page-during-hotplug.patch
mm-memory_hotplug-optimize-memory-hotplug.patch
sparc64-ng4-memset-32-bits-overflow.patch
--
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