lkml.org 
[lkml]   [2011]   [Feb]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [patch] x86, mm: avoid stale tlb entries by clearing prev mm_cpumask after switching mm
    On Thu, Feb 3, 2011 at 10:27 AM, Suresh Siddha
    <suresh.b.siddha@intel.com> wrote:
    >> Actually, for normal entries I could well imagine the code that wants
    >> to do a flush before freeing the page caring.
    >>
    >> So I think the _patch_ may be correct, but the changelog is definitely
    >> not correct, and needs serious surgery to explain what the bug that
    >> this fixes actually is.
    >
    > Linus, I updated the changelog to explain the failing case in more
    > detail. Please review. Thanks.

    So this explains the bug, and the explanation looks good. Except for
    one (large) detail: it has nothing to do with "stale" entries.

    The problematic entries are simply _bogus_, not stale. They were never
    valid to begin with. So the subject and the initial part is very
    misleading.

    The global bit seems to be largely irrelevant too, except for the fact
    that a global bogus entry obviously stays around and causes way more
    trouble. But I could imagine that there could be trouble with entries
    that have conflicting PSE or cacheability issues (causing machine
    checks or something) even if they are ephemeral and not global.

    Linus


    \
     
     \ /
      Last update: 2011-02-03 20:17    [W:0.025 / U:0.708 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site