lkml.org 
[lkml]   [2009]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 1/3]fs/inode: iunique() Optimize Performance
    On Wed, Nov 25, 2009 at 10:09:45PM +0800, Liuweni wrote:
    > ---
    > move the if condition out the while{}.
    > While the function executing, the if
    > condition won't check again and again.
    > And this code won't change the function
    > of iunique().

    That's not true.

    > @@ -838,9 +838,10 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
    > ino_t res;
    >
    > spin_lock(&inode_lock);
    > +
    > + if (counter <= max_reserved)
    > + counter = max_reserved + 1;
    > do {
    > - if (counter <= max_reserved)
    > - counter = max_reserved + 1;
    > res = counter++;

    'counter' is incremented here, so if it wraps around, we'll blunder into
    the reserved space again.

    > head = inode_hashtable + hash(sb, res);
    > inode = find_inode_fast(sb, head, res);
    >
    >
    > --------------
    > Best Regards,
    > Liuweni
    > 2009-11-25
    >
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html

    --
    Matthew Wilcox Intel Open Source Technology Centre
    "Bill, look, we understand that you're interested in selling us this
    operating system, but compare it to ours. We can't possibly take such
    a retrograde step."


    \
     
     \ /
      Last update: 2009-11-25 15:17    [W:0.021 / U:64.384 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site