ipc/msg: mitigate the lock contention with percpu counter

The msg_bytes and msg_hdrs atomic counters are frequently updated when IPC
msg queue is in heavy use, causing heavy cache bounce and overhead. 
Change them to percpu_counter greatly improve the performance.  Since
there is one percpu struct per namespace, additional memory cost is
minimal.  Reading of the count done in msgctl call, which is infrequent. 
So the need to sum up the counts in each CPU is infrequent.

Apply the patch and test the pts/stress-ng-1.4.0
-- system v message passing (160 threads).

Score gain: 3.99x

CPU: ICX 8380 x 2 sockets
Core number: 40 x 2 physical cores
Benchmark: pts/stress-ng-1.4.0
-- system v message passing (160 threads)

[akpm@linux-foundation.org: coding-style cleanups]
[jiebin.sun@intel.com: avoid negative value by overflow in msginfo]
  Link: https://lkml.kernel.org/r/20220920150809.4014944-1-jiebin.sun@intel.com
[akpm@linux-foundation.org: fix min() warnings]
Link: https://lkml.kernel.org/r/20220913192538.3023708-3-jiebin.sun@intel.com
Signed-off-by: Jiebin Sun <jiebin.sun@intel.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vasily Averin <vasily.averin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions