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    SubjectRe: [PATCH] vmscan: Remove if statement that will never trigger
    (2011/07/29 6:05), Jesper Juhl wrote:
    > We have this code in mm/vmscan.c:shrink_slab() :
    > ...
    > if (total_scan < 0) {
    > printk(KERN_ERR "shrink_slab: %pF negative objects to "
    > "delete nr=%ld\n",
    > shrinker->shrink, total_scan);
    > total_scan = max_pass;
    > }
    > ...
    > but since 'total_scan' is of type 'unsigned long' it will never be
    > less than zero, so there is no way we'll ever enter the true branch of
    > this if statement - so let's just remove it.
    >
    > Signed-off-by: Jesper Juhl <jj@chaosbits.net>
    > ---
    > mm/vmscan.c | 6 ------
    > 1 files changed, 0 insertions(+), 6 deletions(-)
    >
    > Compile tested only.
    >
    > diff --git a/mm/vmscan.c b/mm/vmscan.c
    > index 7ef6912..c07d9b1 100644
    > --- a/mm/vmscan.c
    > +++ b/mm/vmscan.c
    > @@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
    > delta *= max_pass;
    > do_div(delta, lru_pages + 1);
    > total_scan += delta;
    > - if (total_scan < 0) {
    > - printk(KERN_ERR "shrink_slab: %pF negative objects to "
    > - "delete nr=%ld\n",
    > - shrinker->shrink, total_scan);
    > - total_scan = max_pass;
    > - }
    >
    > /*
    > * We need to avoid excessive windup on filesystem shrinkers

    Good catch.

    However this seems intended to catch a overflow. So, I'd suggest to make proper
    overflow check instead.




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