On Sun, Mar 23, 2014 at 10:50 AM, KOSAKI Motohiro
<kosaki.motohiro@xxxxxxxxx> wrote:
>> +/**
>> + * vrange_check_purged_pte - Checks ptes for purged pages
>> + *
>> + * Iterates over the ptes in the pmd checking if they have
>> + * purged swap entries.
>> + *
>> + * Sets the vrange_walker.pages_purged to 1 if any were purged.
>> + */
>> +static int vrange_check_purged_pte(pmd_t *pmd, unsigned long addr,
>> + unsigned long end, struct mm_walk *walk)
>> +{
>> + struct vrange_walker *vw = walk->private;
>> + pte_t *pte;
>> + spinlock_t *ptl;
>> +
>> + if (pmd_trans_huge(*pmd))
>> + return 0;
>> + if (pmd_trans_unstable(pmd))
>> + return 0;
>> +
>> + pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
>> + for (; addr != end; pte++, addr += PAGE_SIZE) {
>> + if (!pte_present(*pte)) {
>> + swp_entry_t vrange_entry = pte_to_swp_entry(*pte);
>> +
>> + if (unlikely(is_vpurged_entry(vrange_entry))) {
>> + vw->page_was_purged = 1;
>> + break;
>
> This function only detect there is vpurge entry or not. But
> VRANGE_NONVOLATILE should remove all vpurge entries.
> Otherwise, non-volatiled range still makes SIGBUS.
So in the following patch (3/5), we only SIGBUS if the swap entry
is_vpurged_entry() && the vma is still marked volatile, so this
shouldn't be an issue.
thanks
-john
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