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    SubjectRe: Possible regression: MSI vector leakage since 2.6.18-rc5ish (Unable to repeatedly allocate/free MSI interrupt)
    Eric W. Biederman wrote:
    > Auke Kok <> writes:
    >> Hi,
    >> I've established a regression in the MSI vector/irq allocation routine for both
    >> i386 and x86_64. Our test labs repeatedly modprobe/rmmod the e1000 driver for
    >> serveral minutes which allocates msi vectors and frees them. These tests have
    >> been running fine until 2.6.19.
    >> git-bisecting I've established that in between commit
    >> 04b9267b15206fc902a18de1f78de6c82ca47716 "Eric W. Biederman -- genirq: x86_64
    >> irq: Remove the msi assumption that irq == vector" and commit
    >> f29bd1ba68c8c6a0f50bd678bbd5a26674018f7c "Ingo Molnar -- genirq: convert the
    >> x86_64 architecture to irq-chips" the behaviour broke.
    >> The revisions in between seem to be dependent and give all sorts of other
    >> issues, so it's rather hard for me to bisect that and give trustworthy results.
    >> the e1000 driver hits the 256-mark cycle (I think - it consistently refuses to
    >> do 500 msi irq/vector allocations which is my test case) and throws:
    >> e1000: eth4: e1000_request_irq: Unable to allocate MSI interrupt Error: -16
    >> which is caused by a `if ((err = pci_enable_msi(adapter->pdev))) {` call from
    >> the e1000 driver. It's rather easy to hit this mark with the new 4-port e1000
    >> adapters :).
    >> as for the e1000 code, I can say that even our oldest msi-enabled e1000 driver
    >> works fine with 2.6.18 and under. All kernels from 2.6.19 fail consistently.
    >> I mostly suspect commit 7bd007e480672c99d8656c7b7b12ef0549432c37 at the
    >> moment. Perhaps Eric Biederman can help?
    > Does this patch fix it for you? It looks like i386 vector allocate
    > did not have logic to look through the set of vectors more than once.
    > The code in this patch is a simplified version of what we have
    > on x86_64.

    I highly doubt it - I've seen the problem even on this weeks git on x86_64.
    Moreover, I'm at home for the weekend and testing resources are limited :). I'll
    see what I can do

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      Last update: 2007-01-27 20:09    [W:2.400 / U:0.220 seconds]
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