[lkml]   [2010]   [Nov]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] memcg: use do_div to divide s64 in 32 bit machine.
    On Sun, Nov 7, 2010 at 2:19 AM, Greg Thelen <> wrote:
    > On Fri, Nov 5, 2010 at 6:03 PM,  <> wrote:
    >> On Sat, Nov 06, 2010 at 01:08:53AM +0900, Minchan Kim wrote:
    >>> Use do_div to divide s64 value. Otherwise, build would be failed
    >>> like Dave Young reported.
    >> I thought about that too, but then I asked myself why you would want
    >> to represent a number of pages as signed 64bit type, even on 32 bit?
    > I think the reason that 64 byte type is used for page count in
    > memcontrol.c is because the low level res_counter primitives operate
    > on 64 bit counters, even on 32 bit machines.
    >> Isn't the much better fix to get the types right instead?
    > I agree that consistent types between mem_cgroup_dirty_info() and
    > global_dirty_info() is important.  There seems to be a lot of usage of
    > s64 for page counts in memcontrol.c, which I think is due to the
    > res_counter types.  I think these s64 be switched to unsigned long
    > rather to be consistent with the rest of mm code.  It looks like this
    > will be a clean patch, except for the lowest level where
    > res_counter_read_u64() is used, where some casting may be needed.
    > I'll post a patch for that change.

    Agree. I don't mind it.
    Thanks, Hannes and Greg.

    Kind regards,
    Minchan Kim
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2010-11-06 18:33    [W:0.021 / U:15.688 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site