Messages in this thread | | | Date | Wed, 20 Apr 2011 09:38:23 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] hugetlbfs: simplify destroying inode |
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On Mon, 4 Apr 2011 11:36:56 +0800 Hillf Danton <dhillf@gmail.com> wrote:
> Just before reclaimed by the hugetlbfs inode cache, little difference > could be made by initializing the list head of the dentry member of > vfs inode, thus the operation of initialization could be removed to > simplify the destroy of hugetlbfs inode. > > Signed-off-by: Hillf Danton <gmail.com> > --- > > --- a/fs/hugetlbfs/inode.c 2011-03-30 03:09:48.000000000 +0800 > +++ b/fs/hugetlbfs/inode.c 2011-04-04 11:27:30.000000000 +0800 > @@ -665,7 +665,6 @@ static struct inode *hugetlbfs_alloc_ino > static void hugetlbfs_i_callback(struct rcu_head *head) > { > struct inode *inode = container_of(head, struct inode, i_rcu); > - INIT_LIST_HEAD(&inode->i_dentry); > kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); > }
How well was this tested?
hugetlbfs_inode_cachep has a slab constructor, init_once()->inode_init_once(). The slab protocol requires that objects be returned to the cache in the same state as that which the constructor creates. (It's a bit weird and it would probably be faster and certainly saner if the ctor were run by kmem_cache_alloc()).
inode_init_once() does INIT_LIST_HEAD(&inode->i_dentry), so objects should be returned to the cache in that state. If no other code was already reliably reinitialising ->i_dentry, the patch will add a bug.
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