On 30/08/2017 07:58, Peter Zijlstra wrote:
> On Wed, Aug 30, 2017 at 10:33:50AM +0530, Anshuman Khandual wrote:
>> diff --git a/mm/filemap.c b/mm/filemap.c
>> index a497024..08f3042 100644
>> --- a/mm/filemap.c
>> +++ b/mm/filemap.c
>> @@ -1181,6 +1181,18 @@ int __lock_page_killable(struct page *__page)
>> int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
>> unsigned int flags)
>> {
>> + if (flags & FAULT_FLAG_SPECULATIVE) {
>> + if (flags & FAULT_FLAG_KILLABLE) {
>> + int ret;
>> +
>> + ret = __lock_page_killable(page);
>> + if (ret)
>> + return 0;
>> + } else
>> + __lock_page(page);
>> + return 1;
>> + }
>> +
>> if (flags & FAULT_FLAG_ALLOW_RETRY) {
>> /*
>> * CAUTION! In this case, mmap_sem is not released
>
> Yeah, that looks right.
Hum, I'm wondering if FAULT_FLAG_RETRY_NOWAIT should be forced in the
speculative path in that case to match the semantics of
__lock_page_or_retry().
>
>> @@ -4012,17 +4010,7 @@ int handle_speculative_fault(struct mm_struct *mm, unsigned long address,
>> goto unlock;
>> }
>>
>> + if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
>> trace_spf_vma_notsup(_RET_IP_, vma, address);
>> goto unlock;
>> }
>
> As riel pointed out on IRC slightly later, private file maps also need
> ->anon_vma and those actually have ->vm_ops IIRC so the condition needs
> to be slightly more complicated.
Yes I read again the code and lead to the same conclusion.
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