linux/ipc
Helge Deller b795218075 ipc/shm.c: add RSS and swap size information to /proc/sysvipc/shm
The kernel currently provides no functionality to analyze the RSS and swap
space usage of each individual sysvipc shared memory segment.

This patch adds 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).

SAP products (esp.  the SAP Netweaver ABAP Kernel) uses lots of big shared
memory segments (we often have Linux systems with >= 16GB shm usage).
Sometimes we get customer reports about "slow" system responses and while
looking into their configurations we often find massive swapping activity
on the system.  With this patch it's now easy to see from the command line
if and which shm segments gets swapped out (and how much) and can more
easily give recommendations for system tuning.  Without the patch it's
currently not possible to do such shm analysis at all.

Also...

Add some spaces in front of the "size" field for 64bit kernels to get the
columns correct if you cat the contents of the file.  In
sysvipc_shm_proc_show() the kernel prints the size value in "SPEC_SIZE"
format, which is defined like this:

#if BITS_PER_LONG <= 32
#define SIZE_SPEC "%10lu"
#else
#define SIZE_SPEC "%21lu"
#endif

So, if the header is not adjusted, the columns are not correctly aligned.
I actually tested this on 32- and 64-bit and it seems correct now.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:13 -07:00
..
compat_mq.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
compat.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ipc_sysctl.c sysctl ipc: Remove dead binary sysctl support code. 2009-11-12 02:04:54 -08:00
ipcns_notifier.c ipc: do not use a negative value to re-enable msgmni automatic recomputing 2008-07-25 10:53:42 -07:00
Makefile Add generic sys_ipc wrapper 2010-03-12 15:52:32 -08:00
mq_sysctl.c sysctl ipc: Remove dead binary sysctl support code. 2009-11-12 02:04:54 -08:00
mqueue.c fs: do not assign default i_ino in new_inode 2010-10-25 21:26:11 -04:00
msg.c kernel-wide: replace USHORT_MAX, SHORT_MAX and SHORT_MIN with USHRT_MAX, SHRT_MAX and SHRT_MIN 2010-05-25 08:07:02 -07:00
msgutil.c namespaces: ipc namespaces: implement support for posix msqueues 2009-04-07 08:31:09 -07:00
namespace.c ipcns: make free_ipc_ns() static 2009-06-18 13:03:56 -07:00
sem.c sys_semctl: fix kernel stack leakage 2010-10-01 10:50:58 -07:00
shm.c ipc/shm.c: add RSS and swap size information to /proc/sysvipc/shm 2010-10-27 18:03:13 -07:00
syscall.c ppc64 sys_ipc breakage in 2.6.34-rc2 2010-03-22 09:57:19 -07:00
util.c kernel-wide: replace USHORT_MAX, SHORT_MAX and SHORT_MIN with USHRT_MAX, SHRT_MAX and SHRT_MIN 2010-05-25 08:07:02 -07:00
util.h ipc: unbreak 32-bit shmctl/semctl/msgctl 2009-06-21 12:48:43 -07:00