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HWPOISON: Add basic support for poisoned pages in fault handler v3

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- Add a new VM_FAULT_HWPOISON error code to handle_mm_fault. Right now
architectures have to explicitely enable poison page support, so
this is forward compatible to all architectures. They only need
to add it when they enable poison page support.
- Add poison page handling in swap in fault code

v2: Add missing delayacct_clear_flag (Hidehiro Kawai)
v3: Really use delayacct_clear_flag (Hidehiro Kawai)

Signed-off-by: Andi Kleen <ak@linux.intel.com>
This commit is contained in:
Andi Kleen 2009-09-16 11:50:06 +02:00 • committed by Andi Kleen
commit d1737fdbec
2 changed files with 17 additions and 4 deletions
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3
include/linux/mm.h
View file

@ -685,11 +685,12 @@ static inline int page_mapped(struct page *page)
#define VM_FAULT_SIGBUS 0x0002
#define VM_FAULT_MAJOR 0x0004
#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned page */
#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */
#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */
#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS)
#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)
/*
* Can be called by the pagefault handler when it gets a VM_FAULT_OOM.

14
mm/memory.c
View file

@ -1319,7 +1319,8 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM)
return i ? i : -ENOMEM;
else if (ret & VM_FAULT_SIGBUS)
if (ret &
(VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
return i ? i : -EFAULT;
BUG();
}
@ -2511,8 +2512,15 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto out;
entry = pte_to_swp_entry(orig_pte);
if (unlikely(non_swap_entry(entry))) {
if (is_migration_entry(entry)) {
migration_entry_wait(mm, pmd, address);
} else if (is_hwpoison_entry(entry)) {
ret = VM_FAULT_HWPOISON;
} else {
print_bad_pte(vma, address, orig_pte, NULL);
ret = VM_FAULT_OOM;
}
goto out;
}
delayacct_set_flag(DELAYACCT_PF_SWAPIN);
@ -2536,6 +2544,10 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
/* Had to read the page from swap area: Major fault */
ret = VM_FAULT_MAJOR;
count_vm_event(PGMAJFAULT);
} else if (PageHWPoison(page)) {
ret = VM_FAULT_HWPOISON;
delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
goto out;
}
lock_page(page);