lkml.org 
[lkml]   [2010]   [Dec]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] taskstats: Use better ifdef for alignment
    On Thu, 30 Dec 2010 00:26:34 -0500 Jeff Mahoney <jeffm@suse.com> wrote:

    > On 12/29/2010 07:14 PM, Andrew Morton wrote:
    > > On Wed, 29 Dec 2010 19:12:08 -0500 Jeff Mahoney <jeffm@suse.com> wrote:
    > >
    > >> Commit 4be2c95d added a null field to align the taskstats structure but
    > >> the discussion centered around ia64. The issue exists on other platforms
    > >> with inefficient unaligned access and adding them piecemeal would be
    > >> an unmaintainable mess.
    > >>
    > >> This patch uses Dave Miller's suggestion of using a combination of
    > >> CONFIG_64BIT && !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to determine
    > >> whether alignment is needed.
    > >>
    > >> Note that this will cause breakage on those platforms with applications
    > >> like iotop which had hard-coded offsets into the packet to access the
    > >> taskstats structure.
    > >
    > > That seems a very good reason to not apply the patch.
    > >
    > > Tell us more, please...
    >
    > I don't want to rehash the same discussion

    Please do so. That discussion went on for a long time over many emails
    and multiple iterations of the patch. I personally have forgotten the
    reasoning and if I could remember it, I wouldn't remember which version
    of the patch it applied to.

    Applying a patch which is *known* to break *known* userspace
    applications is a quite extraordinary thing to do. We owe it to people
    to fully explain the reasoning.



    \
     
     \ /
      Last update: 2010-12-30 06:35    [W:0.024 / U:92.644 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site