From: Oscar Salvador <osalvador@suse.de>
To: akpm@linux-foundation.org
Cc: mhocko@suse.com, dan.j.williams@intel.com,
pavel.tatashin@microsoft.com, jglisse@redhat.com,
Jonathan.Cameron@huawei.com, rafael@kernel.org, david@redhat.com,
linux-mm@kvack.org, Oscar Salvador <osalvador@suse.com>,
Oscar Salvador <osalvador@suse.de>
Subject: [PATCH v2 4/5] mm, memory-hotplug: Rework unregister_mem_sect_under_nodes
Date: Tue, 27 Nov 2018 17:20:04 +0100 [thread overview]
Message-ID: <20181127162005.15833-5-osalvador@suse.de> (raw)
In-Reply-To: <20181127162005.15833-1-osalvador@suse.de>
From: Oscar Salvador <osalvador@suse.com>
This tries to address another issue about accessing
unitiliazed pages.
Jonathan reported a problem [1] where we can access steal pages
in case we hot-remove memory without onlining it first.
This time is in unregister_mem_sect_under_nodes.
This function tries to get the nid from the pfn and then
tries to remove the symlink between mem_blk <-> nid and vice versa.
Since we already know the nid in remove_memory(), we can pass
it down the chain to unregister_mem_sect_under_nodes.
There we can just remove the symlinks without the need
to look into the pages.
This also allows us to cleanup unregister_mem_sect_under_nodes.
[1] https://www.spinics.net/lists/linux-mm/msg161316.html
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
drivers/base/memory.c | 9 ++++-----
drivers/base/node.c | 39 ++++++---------------------------------
include/linux/memory.h | 2 +-
include/linux/node.h | 9 ++++-----
mm/memory_hotplug.c | 2 +-
5 files changed, 16 insertions(+), 45 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 0e5985682642..3d8c65d84bea 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -744,8 +744,7 @@ unregister_memory(struct memory_block *memory)
device_unregister(&memory->dev);
}
-static int remove_memory_section(unsigned long node_id,
- struct mem_section *section, int phys_device)
+static int remove_memory_section(unsigned long nid, struct mem_section *section)
{
struct memory_block *mem;
@@ -759,7 +758,7 @@ static int remove_memory_section(unsigned long node_id,
if (!mem)
goto out_unlock;
- unregister_mem_sect_under_nodes(mem, __section_nr(section));
+ unregister_mem_sect_under_nodes(nid, mem);
mem->section_count--;
if (mem->section_count == 0)
@@ -772,12 +771,12 @@ static int remove_memory_section(unsigned long node_id,
return 0;
}
-int unregister_memory_section(struct mem_section *section)
+int unregister_memory_section(int nid, struct mem_section *section)
{
if (!present_section(section))
return -EINVAL;
- return remove_memory_section(0, section, 0);
+ return remove_memory_section(nid, section);
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 86d6cd92ce3d..0858f7f3c7cd 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -453,40 +453,13 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg)
return 0;
}
-/* unregister memory section under all nodes that it spans */
-int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
- unsigned long phys_index)
+/* Remove symlink between node <-> mem_blk */
+void unregister_mem_sect_under_nodes(int nid, struct memory_block *mem_blk)
{
- NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
- unsigned long pfn, sect_start_pfn, sect_end_pfn;
-
- if (!mem_blk) {
- NODEMASK_FREE(unlinked_nodes);
- return -EFAULT;
- }
- if (!unlinked_nodes)
- return -ENOMEM;
- nodes_clear(*unlinked_nodes);
-
- sect_start_pfn = section_nr_to_pfn(phys_index);
- sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
- for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
- int nid;
-
- nid = get_nid_for_pfn(pfn);
- if (nid < 0)
- continue;
- if (!node_online(nid))
- continue;
- 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;
+ 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));
}
int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn)
diff --git a/include/linux/memory.h b/include/linux/memory.h
index a6ddefc60517..d75ec88ca09d 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -113,7 +113,7 @@ extern int register_memory_isolate_notifier(struct notifier_block *nb);
extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
int hotplug_memory_register(int nid, struct mem_section *section);
#ifdef CONFIG_MEMORY_HOTREMOVE
-extern int unregister_memory_section(struct mem_section *);
+extern int unregister_memory_section(int nid, struct mem_section *);
#endif
extern int memory_dev_init(void);
extern int memory_notify(unsigned long val, void *v);
diff --git a/include/linux/node.h b/include/linux/node.h
index 257bb3d6d014..488c1333bb06 100644
--- a/include/linux/node.h
+++ b/include/linux/node.h
@@ -72,8 +72,8 @@ 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,
void *arg);
-extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
- unsigned long phys_index);
+extern void unregister_mem_sect_under_nodes(int nid,
+ struct memory_block *mem_blk);
#ifdef CONFIG_HUGETLBFS
extern void register_hugetlbfs_with_node(node_registration_func_t doregister,
@@ -105,10 +105,9 @@ static inline int register_mem_sect_under_node(struct memory_block *mem_blk,
{
return 0;
}
-static inline int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
- unsigned long phys_index)
+static inline void unregister_mem_sect_under_nodes(int nid,
+ struct memory_block *mem_blk)
{
- return 0;
}
static inline void register_hugetlbfs_with_node(node_registration_func_t reg,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 4fe42ccb0be4..49b91907e19e 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -544,7 +544,7 @@ static int __remove_section(int nid, struct mem_section *ms,
if (!valid_section(ms))
return ret;
- ret = unregister_memory_section(ms);
+ ret = unregister_memory_section(nid, ms);
if (ret)
return ret;
--
2.13.6
next prev parent reply other threads:[~2018-11-27 16:42 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-27 16:20 [PATCH v2 0/5] Do not touch pages in hot-remove path Oscar Salvador
2018-11-27 16:20 ` [PATCH v2 1/5] mm, memory_hotplug: Add nid parameter to arch_remove_memory Oscar Salvador
2018-11-27 16:20 ` [PATCH v2 2/5] kernel, resource: Check for IORESOURCE_SYSRAM in release_mem_region_adjustable Oscar Salvador
2018-11-27 16:20 ` [PATCH v2 3/5] mm, memory_hotplug: Move zone/pages handling to offline stage Oscar Salvador
2018-11-28 7:52 ` Mike Rapoport
2018-11-28 14:25 ` osalvador
2018-11-28 14:15 ` osalvador
2018-11-27 16:20 ` Oscar Salvador [this message]
2019-03-24 6:48 ` [PATCH v2 4/5] mm, memory-hotplug: Rework unregister_mem_sect_under_nodes Anshuman Khandual
2019-03-25 7:40 ` Oscar Salvador
2019-03-25 8:04 ` Michal Hocko
2019-03-25 8:14 ` Oscar Salvador
2018-11-27 16:20 ` [PATCH v2 5/5] mm, memory_hotplug: Refactor shrink_zone/pgdat_span Oscar Salvador
2018-11-28 6:50 ` Michal Hocko
2018-11-28 7:07 ` Oscar Salvador
2018-11-28 10:03 ` David Hildenbrand
2018-11-28 10:14 ` Michal Hocko
2018-11-28 11:00 ` osalvador
2018-11-28 12:31 ` Michal Hocko
2018-11-28 12:51 ` osalvador
2018-11-28 13:08 ` Michal Hocko
2018-11-28 13:18 ` osalvador
2018-11-28 15:50 ` Michal Hocko
2018-11-28 16:02 ` osalvador
2018-11-29 9:29 ` osalvador
2018-11-28 13:09 ` osalvador
2018-11-27 16:25 [PATCH v2 4/5] mm, memory-hotplug: Rework unregister_mem_sect_under_nodes Oscar Salvador
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