Messages in this thread | | | Date | Tue, 26 May 2009 21:55:26 +0900 | From | Hidehiro Kawai <> | Subject | Re: [PATCH] [7/16] POISON: Add basic support for poisoned pages in fault handler |
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Andi Kleen wrote:
> - Add a new VM_FAULT_POISON 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 > > Signed-off-by: Andi Kleen <ak@linux.intel.com> > > --- > include/linux/mm.h | 3 ++- > mm/memory.c | 17 ++++++++++++++--- > 2 files changed, 16 insertions(+), 4 deletions(-) > > Index: linux/mm/memory.c > =================================================================== > --- linux.orig/mm/memory.c 2009-04-07 16:39:24.000000000 +0200 > +++ linux/mm/memory.c 2009-04-07 16:43:06.000000000 +0200 > @@ -1315,7 +1315,8 @@ > if (ret & VM_FAULT_ERROR) { > if (ret & VM_FAULT_OOM) > return i ? i : -ENOMEM; > - else if (ret & VM_FAULT_SIGBUS) > + if (ret & > + (VM_FAULT_POISON|VM_FAULT_SIGBUS)) > return i ? i : -EFAULT; > BUG(); > } > @@ -2426,8 +2427,15 @@ > goto out; > > entry = pte_to_swp_entry(orig_pte); > - if (is_migration_entry(entry)) { > - migration_entry_wait(mm, pmd, address); > + if (unlikely(non_swap_entry(entry))) { > + if (is_migration_entry(entry)) { > + migration_entry_wait(mm, pmd, address); > + } else if (is_poison_entry(entry)) { > + ret = VM_FAULT_POISON; > + } else { > + print_bad_pte(vma, address, pte, NULL); > + ret = VM_FAULT_OOM; > + } > goto out; > } > delayacct_set_flag(DELAYACCT_PF_SWAPIN); > @@ -2451,6 +2459,9 @@ > /* Had to read the page from swap area: Major fault */ > ret = VM_FAULT_MAJOR; > count_vm_event(PGMAJFAULT); > + } else if (PagePoison(page)) { > + ret = VM_FAULT_POISON;
delayacct_clear_flag(DELAYACCT_PF_SWAPIN) would be needed here.
> + goto out; > } > > lock_page(page);
Regards, -- Hidehiro Kawai Hitachi, Systems Development Laboratory Linux Technology Center
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