The patch titled
Subject: mm/hwpoison: introduce per-memory_block hwpoison counter
has been added to the -mm mm-unstable branch. Its filename is
mm-hwpoison-introduce-per-memory_block-hwpoison-counter.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hwpoison-introduce-per-memory_block-hwpoison-counter.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Subject: mm/hwpoison: introduce per-memory_block hwpoison counter
Date: Wed, 21 Sep 2022 18:13:59 +0900
Currently PageHWPoison flag does not behave well when experiencing memory
hotremove/hotplug. Any data field in struct page is unreliable when the
associated memory is offlined, and the current mechanism can't tell
whether a memory section is onlined because a new memory devices is
installed or because previous failed offline operations are undone.
Especially if there's a hwpoisoned memory, it's unclear what the best
option is.
So introduce a new mechanism to make struct memory_block remember that a
memory block has hwpoisoned memory inside it. And make any online event
fail if the onlined memory block contains hwpoison. struct memory_block
is freed and reallocated over ACPI-based hotremove/hotplug, but not over
sysfs-based hotremove/hotplug. So it's desirable to implement hwpoison
counter on this struct.
Note that clear_hwpoisoned_pages() is relocated to be called earlier than
now, just before unregistering struct memory_block. Otherwise, the
per-memory_block hwpoison counter is freed and we fail to adjust global
hwpoison counter properly.
Link: https://lkml.kernel.org/r/20220921091359.25889-5-naoya.horiguchi@xxxxxxxxx
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/drivers/base/memory.c~mm-hwpoison-introduce-per-memory_block-hwpoison-counter
+++ a/drivers/base/memory.c
@@ -183,6 +183,9 @@ static int memory_block_online(struct me
struct zone *zone;
int ret;
+ if (atomic_long_read(&mem->nr_hwpoison))
+ return -EHWPOISON;
+
zone = zone_for_pfn_range(mem->online_type, mem->nid, mem->group,
start_pfn, nr_pages);
@@ -864,6 +867,7 @@ void remove_memory_block_devices(unsigne
mem = find_memory_block_by_id(block_id);
if (WARN_ON_ONCE(!mem))
continue;
+ clear_hwpoisoned_pages(atomic_long_read(&mem->nr_hwpoison));
unregister_memory_block_under_nodes(mem);
remove_memory_block(mem);
}
@@ -1164,3 +1168,35 @@ int walk_dynamic_memory_groups(int nid,
}
return ret;
}
+
+#ifdef CONFIG_MEMORY_FAILURE
+
+void memblk_nr_poison_inc(unsigned long pfn)
+{
+ const unsigned long block_id = pfn_to_block_id(pfn);
+ struct memory_block *mem = find_memory_block_by_id(block_id);
+
+ if (mem)
+ atomic_long_inc(&mem->nr_hwpoison);
+}
+
+void memblk_nr_poison_sub(unsigned long pfn, long i)
+{
+ const unsigned long block_id = pfn_to_block_id(pfn);
+ struct memory_block *mem = find_memory_block_by_id(block_id);
+
+ if (mem)
+ atomic_long_sub(i, &mem->nr_hwpoison);
+}
+
+unsigned long memblk_nr_poison(unsigned long pfn)
+{
+ const unsigned long block_id = pfn_to_block_id(pfn);
+ struct memory_block *mem = find_memory_block_by_id(block_id);
+
+ if (mem)
+ return atomic_long_read(&mem->nr_hwpoison);
+ return 0;
+}
+
+#endif
--- a/include/linux/memory.h~mm-hwpoison-introduce-per-memory_block-hwpoison-counter
+++ a/include/linux/memory.h
@@ -85,6 +85,9 @@ struct memory_block {
unsigned long nr_vmemmap_pages;
struct memory_group *group; /* group (if any) for this block */
struct list_head group_next; /* next block inside memory group */
+#ifdef CONFIG_MEMORY_FAILURE
+ atomic_long_t nr_hwpoison;
+#endif
};
int arch_get_memory_phys_device(unsigned long start_pfn);
--- a/include/linux/mm.h~mm-hwpoison-introduce-per-memory_block-hwpoison-counter
+++ a/include/linux/mm.h
@@ -3280,6 +3280,10 @@ extern int soft_offline_page(unsigned lo
#ifdef CONFIG_MEMORY_FAILURE
extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags);
extern void num_poisoned_pages_inc(unsigned long pfn);
+extern void memblk_nr_poison_inc(unsigned long pfn);
+extern void memblk_nr_poison_sub(unsigned long pfn, long i);
+extern unsigned long memblk_nr_poison(unsigned long pfn);
+extern void clear_hwpoisoned_pages(long nr_poison);
#else
static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
{
@@ -3289,6 +3293,10 @@ static inline int __get_huge_page_for_hw
static inline void num_poisoned_pages_inc(unsigned long pfn)
{
}
+
+static inline void clear_hwpoisoned_pages(long nr_poison)
+{
+}
#endif
#ifndef arch_memory_failure
--- a/mm/internal.h~mm-hwpoison-introduce-per-memory_block-hwpoison-counter
+++ a/mm/internal.h
@@ -708,14 +708,6 @@ extern u64 hwpoison_filter_flags_value;
extern u64 hwpoison_filter_memcg;
extern u32 hwpoison_filter_enable;
-#ifdef CONFIG_MEMORY_FAILURE
-void clear_hwpoisoned_pages(struct page *memmap, int nr_pages);
-#else
-static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
-{
-}
-#endif
-
extern unsigned long __must_check vm_mmap_pgoff(struct file *, unsigned long,
unsigned long, unsigned long,
unsigned long, unsigned long);
--- a/mm/memory-failure.c~mm-hwpoison-introduce-per-memory_block-hwpoison-counter
+++ a/mm/memory-failure.c
@@ -74,14 +74,17 @@ atomic_long_t num_poisoned_pages __read_
static bool hw_memory_failure __read_mostly = false;
-static inline void num_poisoned_pages_inc(unsigned long pfn)
+void num_poisoned_pages_inc(unsigned long pfn)
{
atomic_long_inc(&num_poisoned_pages);
+ memblk_nr_poison_inc(pfn);
}
static inline void num_poisoned_pages_sub(unsigned long pfn, long i)
{
atomic_long_sub(i, &num_poisoned_pages);
+ if (pfn != -1UL)
+ memblk_nr_poison_sub(pfn, i);
}
/*
@@ -2414,6 +2417,10 @@ int unpoison_memory(unsigned long pfn)
unlock_mutex:
mutex_unlock(&mf_mutex);
if (!ret || freeit) {
+ /*
+ * TODO: per-memory_block counter might break when the page
+ * size to be unpoisoned is larger than a memory_block.
+ */
num_poisoned_pages_sub(pfn, count);
unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
page_to_pfn(p), &unpoison_rs);
@@ -2618,25 +2625,7 @@ retry:
return ret;
}
-void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
+void clear_hwpoisoned_pages(long nr_poison)
{
- int i, total = 0;
-
- /*
- * A further optimization is to have per section refcounted
- * num_poisoned_pages. But that would need more space per memmap, so
- * for now just do a quick global check to speed up this routine in the
- * absence of bad pages.
- */
- if (atomic_long_read(&num_poisoned_pages) == 0)
- return;
-
- for (i = 0; i < nr_pages; i++) {
- if (PageHWPoison(&memmap[i])) {
- total++;
- ClearPageHWPoison(&memmap[i]);
- }
- }
- if (total)
- num_poisoned_pages_sub(total);
+ num_poisoned_pages_sub(-1UL, nr_poison);
}
--- a/mm/sparse.c~mm-hwpoison-introduce-per-memory_block-hwpoison-counter
+++ a/mm/sparse.c
@@ -926,8 +926,6 @@ void sparse_remove_section(struct mem_se
unsigned long nr_pages, unsigned long map_offset,
struct vmem_altmap *altmap)
{
- clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset,
- nr_pages - map_offset);
section_deactivate(pfn, nr_pages, altmap);
}
#endif /* CONFIG_MEMORY_HOTPLUG */
_
Patches currently in -mm which might be from naoya.horiguchi@xxxxxxx are
mm-huge_memory-use-pfn_to_online_page-in-split_huge_pages_all.patch
mmhwpoisonhugetlbmemory_hotplug-hotremove-memory-section-with-hwpoisoned-hugepage.patch
mm-hwpoison-move-definitions-of-num_poisoned_pages_-to-memory-failurec.patch
mm-hwpoison-pass-pfn-to-num_poisoned_pages_.patch
mm-hwpoison-introduce-per-memory_block-hwpoison-counter.patch
