Messages in this thread | | | Date | Wed, 17 Jun 2015 15:05:19 -0700 | From | Mike Kravetz <> | Subject | Re: [RFC v4 PATCH 2/9] mm/hugetlb: expose hugetlb fault mutex for use by fallocate |
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On 06/11/2015 03:46 PM, Davidlohr Bueso wrote: > On Thu, 2015-06-11 at 14:01 -0700, Mike Kravetz wrote: >> /* Forward declaration */ >> static int hugetlb_acct_memory(struct hstate *h, long delta); >> @@ -3324,7 +3324,8 @@ static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, >> unsigned long key[2]; >> u32 hash; >> >> - if (vma->vm_flags & VM_SHARED) { >> + /* !vma implies this was called from hugetlbfs fallocate code */ >> + if (!vma || vma->vm_flags & VM_SHARED) { > > That !vma is icky, and really no need for it: hugetlbfs_fallocate(), for > example, already passes [pseudo]vma->vm_flags with VM_SHARED, and you > say it yourself in the comment. Do you see any reason why we cannot just > keep the vma->vm_flags & VM_SHARED check? >
Ah, I did not recall all the users of this code until I went to change it. The other user is truncate_hugapages() which will now be used for fallocate hole punch. Truncate like fallocate is an inode operation and there is no specific vma. I can create a pseudo-vma here as well just to pass the flag. I guess that would at least be consistent with the other user.
-- Mike Kravetz
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