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    SubjectRe: [PATCH 4/7] zram/xvmalloc: free bit block insertion optimization
    On Wed, Jan 26, 2011 at 8:40 PM, Robert Jennings <> wrote:
    > * Pekka Enberg ( wrote:
    >> On Wed, Jan 26, 2011 at 7:25 PM, Robert Jennings <> wrote:
    >> > There is no need to set the bits in the first- and second-level indices
    >> > to indicate a free page when we know that a free page existed at this
    >> > level.
    >> >
    >> > Signed-off-by: Robert Jennings <>
    >> Why is it not necessary? I don't know that part of the code well
    >> enough to tell if this patch is safe or not.
    > This change is in a conditional block which is entered only when there is
    > an existing data block on the freelist where the insert has taken place.
    > The new block is pushed onto the freelist stack and this conditional block
    > is updating links in the prior stack head to point to the new stack head.
    > After this conditional block the first-/second-level indices are updated
    > to indicate that there is a free block at this location.
    > This patch adds an immediate return from the conditional block to avoid
    > setting bits again to indicate a free block on this freelist. They would
    > already be set because there was an existing free block on this freelist.

    Some of that information could be put in the changelog.

    Reviewed-by: Pekka Enberg <>

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      Last update: 2011-01-26 19:53    [W:0.026 / U:3.732 seconds]
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