Messages in this thread | | | Date | Thu, 12 Aug 2010 13:10:05 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] ipc/shm.c: add RSS and swap size information to /proc/sysvipc/shm |
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On Wed, 11 Aug 2010 22:13:45 +0200 Helge Deller <deller@gmx.de> wrote:
> The kernel currently provides no functionality to analyze the RSS > and swap space usage of each individual sysvipc shared memory segment. > > This patch add this info for each existing shm segment by extending > the output of /proc/sysvipc/shm by two columns for RSS and swap. > > Since shmctl(SHM_INFO) already provides a similiar calculation (it > currently sums up all RSS/swap info for all segments), I did split > out a static function which is now used by the /proc/sysvipc/shm > output and shmctl(SHM_INFO). >
I suppose that could be useful, although it would be most interesting to hear why _you_ consider it useful?
But is it useful enough to risk breaking existing code which parses that file? The risk is not great, but it's there.
> > --- > > shm.c | 63 ++++++++++++++++++++++++++++++++++++++++++--------------------- > 1 file changed, 42 insertions(+), 21 deletions(-) > > > diff --git a/ipc/shm.c b/ipc/shm.c > --- a/ipc/shm.c > +++ b/ipc/shm.c > @@ -108,7 +108,11 @@ void __init shm_init (void) > { > shm_init_ns(&init_ipc_ns); > ipc_init_proc_interface("sysvipc/shm", > - " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", > +#if BITS_PER_LONG <= 32 > + " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime RSS swap\n", > +#else > + " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime RSS swap\n",
This adds 11 new spaces between "perms" and "size", only on 64-bit machines. That was unchangelogged and adds another (smaller) risk of breaking things. Please explain.
This interface is really old and crufty and horrid, but I guess that there's not a lot we can do about that :(
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