@@ -3174,6 +3174,7 @@ enum mf_flags {
MF_ACTION_REQUIRED = 1 << 1,
MF_MUST_KILL = 1 << 2,
MF_SOFT_OFFLINE = 1 << 3,
+ MF_UNPOISON = 1 << 4,
};
extern int memory_failure(unsigned long pfn, int flags);
extern void memory_failure_queue(unsigned long pfn, int flags);
@@ -522,7 +522,11 @@ PAGEFLAG_FALSE(Uncached, uncached)
PAGEFLAG(HWPoison, hwpoison, PF_ANY)
TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
#define __PG_HWPOISON (1UL << PG_hwpoison)
+#define MAGIC_HWPOISON 0x48575053U /* HWPS */
+extern void SetPageHWPoisonTakenOff(struct page *page);
+extern void ClearPageHWPoisonTakenOff(struct page *page);
extern bool take_page_off_buddy(struct page *page);
+extern bool put_page_back_buddy(struct page *page);
#else
PAGEFLAG_FALSE(HWPoison, hwpoison)
#define __PG_HWPOISON 0
@@ -1160,6 +1160,22 @@ static int page_action(struct page_state
return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY;
}
+static inline bool PageHWPoisonTakenOff(struct page *page)
+{
+ return PageHWPoison(page) && page_private(page) == MAGIC_HWPOISON;
+}
+
+void SetPageHWPoisonTakenOff(struct page *page)
+{
+ set_page_private(page, MAGIC_HWPOISON);
+}
+
+void ClearPageHWPoisonTakenOff(struct page *page)
+{
+ if (PageHWPoison(page))
+ set_page_private(page, 0);
+}
+
/*
* Return true if a page type of a given page is supported by hwpoison
* mechanism (while handling could fail), otherwise false. This function
@@ -1262,6 +1278,27 @@ out:
return ret;
}
+static int __get_unpoison_page(struct page *page)
+{
+ struct page *head = compound_head(page);
+ int ret = 0;
+ bool hugetlb = false;
+
+ ret = get_hwpoison_huge_page(head, &hugetlb);
+ if (hugetlb)
+ return ret;
+
+ /*
+ * PageHWPoisonTakenOff pages are not only marked as PG_hwpoison,
+ * but also isolated from buddy freelist, so need to identify the
+ * state and have to cancel both operations to unpoison.
+ */
+ if (PageHWPoisonTakenOff(page))
+ return -EHWPOISON;
+
+ return get_page_unless_zero(page) ? 1 : 0;
+}
+
/**
* get_hwpoison_page() - Get refcount for memory error handling
* @p: Raw error page (hit by memory error)
@@ -1278,18 +1315,26 @@ out:
* extra care for the error page's state (as done in __get_hwpoison_page()),
* and has some retry logic in get_any_page().
*
+ * When called from unpoison_memory(), the caller should already ensure that
+ * the given page has PG_hwpoison. So it's never reused for other page
+ * allocations, and __get_unpoison_page() never races with them.
+ *
* Return: 0 on failure,
* 1 on success for in-use pages in a well-defined state,
* -EIO for pages on which we can not handle memory errors,
* -EBUSY when get_hwpoison_page() has raced with page lifecycle
- * operations like allocation and free.
+ * operations like allocation and free,
+ * -EHWPOISON when the page is hwpoisoned and taken off from buddy.
*/
static int get_hwpoison_page(struct page *p, unsigned long flags)
{
int ret;
zone_pcp_disable(page_zone(p));
- ret = get_any_page(p, flags);
+ if (flags & MF_UNPOISON)
+ ret = __get_unpoison_page(p);
+ else
+ ret = get_any_page(p, flags);
zone_pcp_enable(page_zone(p));
return ret;
@@ -1937,6 +1982,28 @@ core_initcall(memory_failure_init);
pr_info(fmt, pfn); \
})
+static inline int clear_page_hwpoison(struct ratelimit_state *rs, struct page *p)
+{
+ if (TestClearPageHWPoison(p)) {
+ unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
+ page_to_pfn(p), rs);
+ num_poisoned_pages_dec();
+ return 1;
+ }
+ return 0;
+}
+
+static inline int unpoison_taken_off_page(struct ratelimit_state *rs,
+ struct page *p)
+{
+ if (put_page_back_buddy(p)) {
+ unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
+ page_to_pfn(p), rs);
+ return 0;
+ }
+ return -EBUSY;
+}
+
/**
* unpoison_memory - Unpoison a previously poisoned page
* @pfn: Page number of the to be unpoisoned page
@@ -1953,9 +2020,7 @@ int unpoison_memory(unsigned long pfn)
{
struct page *page;
struct page *p;
- int freeit = 0;
- int ret = 0;
- unsigned long flags = 0;
+ int ret = -EBUSY;
static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
@@ -1991,24 +2056,30 @@ int unpoison_memory(unsigned long pfn)
goto unlock_mutex;
}
- if (!get_hwpoison_page(p, flags)) {
- if (TestClearPageHWPoison(p))
- num_poisoned_pages_dec();
- unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n",
- pfn, &unpoison_rs);
+ if (PageSlab(page) || PageTable(page))
goto unlock_mutex;
- }
- if (TestClearPageHWPoison(page)) {
- unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
- pfn, &unpoison_rs);
- num_poisoned_pages_dec();
- freeit = 1;
- }
+ ret = get_hwpoison_page(p, MF_UNPOISON);
+ if (!ret) {
+ if (clear_page_hwpoison(&unpoison_rs, page))
+ ret = 0;
+ else
+ ret = -EBUSY;
+ } else if (ret < 0) {
+ if (ret == -EHWPOISON) {
+ ret = unpoison_taken_off_page(&unpoison_rs, p);
+ } else
+ unpoison_pr_info("Unpoison: failed to grab page %#lx\n",
+ pfn, &unpoison_rs);
+ } else {
+ int freeit = clear_page_hwpoison(&unpoison_rs, p);
- put_page(page);
- if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
put_page(page);
+ if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) {
+ put_page(page);
+ ret = 0;
+ }
+ }
unlock_mutex:
mutex_unlock(&mf_mutex);
@@ -19,6 +19,7 @@
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/swap.h>
+#include <linux/swapops.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/jiffies.h>
@@ -9508,6 +9509,7 @@ bool take_page_off_buddy(struct page *pa
del_page_from_free_list(page_head, zone, page_order);
break_down_buddy_pages(zone, page_head, page, 0,
page_order, migratetype);
+ SetPageHWPoisonTakenOff(page);
if (!is_migrate_isolate(migratetype))
__mod_zone_freepage_state(zone, -1, migratetype);
ret = true;
@@ -9519,6 +9521,31 @@ bool take_page_off_buddy(struct page *pa
spin_unlock_irqrestore(&zone->lock, flags);
return ret;
}
+
+/*
+ * Cancel takeoff done by take_page_off_buddy().
+ */
+bool put_page_back_buddy(struct page *page)
+{
+ struct zone *zone = page_zone(page);
+ unsigned long pfn = page_to_pfn(page);
+ unsigned long flags;
+ int migratetype = get_pfnblock_migratetype(page, pfn);
+ bool ret = false;
+
+ spin_lock_irqsave(&zone->lock, flags);
+ if (put_page_testzero(page)) {
+ ClearPageHWPoisonTakenOff(page);
+ __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE);
+ if (TestClearPageHWPoison(page)) {
+ num_poisoned_pages_dec();
+ ret = true;
+ }
+ }
+ spin_unlock_irqrestore(&zone->lock, flags);
+
+ return ret;
+}
#endif
#ifdef CONFIG_ZONE_DMA