The patch titled
Subject: mm/hugetlb: setup hugetlb_falloc during fallocate hole punch
has been added to the -mm tree. Its filename is
mm-hugetlb-setup-hugetlb_falloc-during-fallocate-hole-punch.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-setup-hugetlb_falloc-during-fallocate-hole-punch.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-setup-hugetlb_falloc-during-fallocate-hole-punch.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: mm/hugetlb: setup hugetlb_falloc during fallocate hole punch
When performing a fallocate hole punch, set up a hugetlb_falloc struct and
make i_private point to it. i_private will point to this struct for the
duration of the operation. At the end of the operation, wake up anyone
who faulted on the hole and is on the waitq.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 32 +++++++++++++++++++++++++++++---
1 file changed, 29 insertions(+), 3 deletions(-)
diff -puN fs/hugetlbfs/inode.c~mm-hugetlb-setup-hugetlb_falloc-during-fallocate-hole-punch fs/hugetlbfs/inode.c
--- a/fs/hugetlbfs/inode.c~mm-hugetlb-setup-hugetlb_falloc-during-fallocate-hole-punch
+++ a/fs/hugetlbfs/inode.c
@@ -507,6 +507,7 @@ static long hugetlbfs_punch_hole(struct
{
struct hstate *h = hstate_inode(inode);
loff_t hpage_size = huge_page_size(h);
+ unsigned long hpage_shift = huge_page_shift(h);
loff_t hole_start, hole_end;
/*
@@ -518,8 +519,30 @@ static long hugetlbfs_punch_hole(struct
if (hole_end > hole_start) {
struct address_space *mapping = inode->i_mapping;
+ DECLARE_WAIT_QUEUE_HEAD_ONSTACK(hugetlb_falloc_waitq);
+ /*
+ * Page faults on the area to be hole punched must be stopped
+ * during the operation. Initialize struct and have
+ * inode->i_private point to it.
+ */
+ struct hugetlb_falloc hugetlb_falloc = {
+ .waitq = &hugetlb_falloc_waitq,
+ .start = hole_start >> hpage_shift,
+ .end = hole_end >> hpage_shift
+ };
mutex_lock(&inode->i_mutex);
+
+ /*
+ * inode->i_private will be checked in the page fault path.
+ * The locking assures that all writes to the structure are
+ * complete before assigning to i_private. A fault on another
+ * CPU will see the fully initialized structure.
+ */
+ spin_lock(&inode->i_lock);
+ inode->i_private = &hugetlb_falloc;
+ spin_unlock(&inode->i_lock);
+
i_mmap_lock_write(mapping);
if (!RB_EMPTY_ROOT(&mapping->i_mmap))
hugetlb_vmdelete_list(&mapping->i_mmap,
@@ -527,6 +550,12 @@ static long hugetlbfs_punch_hole(struct
hole_end >> PAGE_SHIFT);
i_mmap_unlock_write(mapping);
remove_inode_hugepages(inode, hole_start, hole_end);
+
+ spin_lock(&inode->i_lock);
+ inode->i_private = NULL;
+ wake_up_all(&hugetlb_falloc_waitq);
+ spin_unlock(&inode->i_lock);
+
mutex_unlock(&inode->i_mutex);
}
@@ -647,9 +676,6 @@ static long hugetlbfs_fallocate(struct f
if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
i_size_write(inode, offset + len);
inode->i_ctime = CURRENT_TIME;
- spin_lock(&inode->i_lock);
- inode->i_private = NULL;
- spin_unlock(&inode->i_lock);
out:
mutex_unlock(&inode->i_mutex);
return error;
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
mm-hugetlb-define-hugetlb_falloc-structure-for-hole-punch-race.patch
mm-hugetlb-setup-hugetlb_falloc-during-fallocate-hole-punch.patch
mm-hugetlb-page-faults-check-for-fallocate-hole-punch-in-progress-and-wait.patch
mm-hugetlb-unmap-pages-to-remove-if-page-fault-raced-with-hole-punch.patch
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