The patch titled
Subject: mm/memory_hotplug: make unregister_memory_block_under_nodes() never fail
has been added to the -mm tree. Its filename is
mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail.patch
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/memory_hotplug: make unregister_memory_block_under_nodes() never fail
We really don't want anything during memory hotunplug to fail. We always
pass a valid memory block device, that check can go. Avoid allocating
memory and eventually failing. As we are always called under lock, we can
use a static piece of memory. This avoids having to put the structure
onto the stack, having to guess about the stack size of callers.
Patch inspired by a patch from Oscar Salvador.
In the future, there might be no need to iterate over nodes at all.
mem->nid should tell us exactly what to remove. Memory block devices with
mixed nodes (added during boot) should properly fenced off and never
removed.
Link: http://lkml.kernel.org/r/20190527111152.16324-11-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Andrew Banman <andrew.banman@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Arun KS <arunks@xxxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Chintan Pandya <cpandya@xxxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Jun Yao <yaojun8558363@xxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Mathieu Malaterre <malat@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: "mike.travis@xxxxxxx" <mike.travis@xxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/node.c | 18 +++++-------------
include/linux/node.h | 5 ++---
2 files changed, 7 insertions(+), 16 deletions(-)
--- a/drivers/base/node.c~mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail
+++ a/drivers/base/node.c
@@ -803,20 +803,14 @@ int register_mem_sect_under_node(struct
/*
* Unregister memory block device under all nodes that it spans.
+ * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes).
*/
-int unregister_memory_block_under_nodes(struct memory_block *mem_blk)
+void unregister_memory_block_under_nodes(struct memory_block *mem_blk)
{
- NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
unsigned long pfn, sect_start_pfn, sect_end_pfn;
+ static nodemask_t unlinked_nodes;
- if (!mem_blk) {
- NODEMASK_FREE(unlinked_nodes);
- return -EFAULT;
- }
- if (!unlinked_nodes)
- return -ENOMEM;
- nodes_clear(*unlinked_nodes);
-
+ nodes_clear(unlinked_nodes);
sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
@@ -827,15 +821,13 @@ int unregister_memory_block_under_nodes(
continue;
if (!node_online(nid))
continue;
- if (node_test_and_set(nid, *unlinked_nodes))
+ if (node_test_and_set(nid, unlinked_nodes))
continue;
sysfs_remove_link(&node_devices[nid]->dev.kobj,
kobject_name(&mem_blk->dev.kobj));
sysfs_remove_link(&mem_blk->dev.kobj,
kobject_name(&node_devices[nid]->dev.kobj));
}
- NODEMASK_FREE(unlinked_nodes);
- return 0;
}
int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn)
--- a/include/linux/node.h~mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail
+++ a/include/linux/node.h
@@ -139,7 +139,7 @@ extern int register_cpu_under_node(unsig
extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid);
extern int register_mem_sect_under_node(struct memory_block *mem_blk,
void *arg);
-extern int unregister_memory_block_under_nodes(struct memory_block *mem_blk);
+extern void unregister_memory_block_under_nodes(struct memory_block *mem_blk);
extern int register_memory_node_under_compute_node(unsigned int mem_nid,
unsigned int cpu_nid,
@@ -175,9 +175,8 @@ static inline int register_mem_sect_unde
{
return 0;
}
-static inline int unregister_memory_block_under_nodes(struct memory_block *mem_blk)
+static inline void unregister_memory_block_under_nodes(struct memory_block *mem_blk)
{
- return 0;
}
static inline void register_hugetlbfs_with_node(node_registration_func_t reg,
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-memory_hotplug-simplify-and-fix-check_hotplug_memory_range.patch
s390x-mm-fail-when-an-altmap-is-used-for-arch_add_memory.patch
s390x-mm-implement-arch_remove_memory.patch
arm64-mm-add-temporary-arch_remove_memory-implementation.patch
drivers-base-memory-pass-a-block_id-to-init_memory_block.patch
mm-memory_hotplug-allow-arch_remove_pages-without-config_memory_hotremove.patch
mm-memory_hotplug-create-memory-block-devices-after-arch_add_memory.patch
mm-memory_hotplug-drop-mhp_memblock_api.patch
mm-memory_hotplug-remove-memory-block-devices-before-arch_remove_memory.patch
mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail.patch
mm-memory_hotplug-remove-zone-parameter-from-sparse_remove_one_section.patch
