lkml.org 
[lkml]   [2012]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH 1/3] sysfs: Compact sysfs_dirent s_flags into a byte.
    Greg Kroah-Hartman <gregkh@linuxfoundation.org> writes:

    > On Thu, Mar 08, 2012 at 01:34:22PM -0800, Eric W. Biederman wrote:
    >>
    >> In an effort to keep sysfs_dirent small used the smallest
    >> basic type I can for sysfs s_flags.
    >>
    >> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
    >> ---
    >> fs/sysfs/sysfs.h | 10 +++++-----
    >> 1 files changed, 5 insertions(+), 5 deletions(-)
    >>
    >> diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
    >> index 6289a00..c76c932 100644
    >> --- a/fs/sysfs/sysfs.h
    >> +++ b/fs/sysfs/sysfs.h
    >> @@ -76,7 +76,7 @@ struct sysfs_dirent {
    >> struct sysfs_elem_bin_attr s_bin_attr;
    >> };
    >>
    >> - unsigned short s_flags;
    >> + unsigned char s_flags;
    >> umode_t s_mode;
    >> unsigned int s_ino;
    >> struct sysfs_inode_attrs *s_iattr;
    >
    > Are you sure this saved you any real space here? Have you use pahole (I
    > think that's the tool name) to determine if there are holes in the
    > structure? Given that you moved this to a smaller variable, yet there
    > are pointers later on, odds are nothing changed at all overall.
    >
    > Verification would be good to have, to see if this work was really worth
    > it, right?

    The next patch stuffs an 8bit nlink in the hole. I was making room so
    we don't have to grow sysfs_dirent.

    Eric


    \
     
     \ /
      Last update: 2012-03-09 03:49    [W:0.041 / U:3.176 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site