diff options
| author | Waiman Long <longman@redhat.com> | 2017-02-08 10:44:14 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2017-02-09 17:01:39 +1100 |
| commit | b4d623f67460595ba2c37eefceec33a3cea97422 (patch) | |
| tree | 5e6f41eb9621b4a18fdd320f1af83d7a41085f12 /tools | |
| parent | 9ef13af6296977af2e8443c1b5b304dd1b50a1e4 (diff) | |
debugobjects: track number of kmem_cache_alloc/kmem_cache_free done
Patch series "debugobjects: Reduce global pool_lock contention", v2.
This patchset aims to reduce contention of the global pool_lock while
improving performance at the same time. It is done to resolve the
following soft lockup problem with a debug kernel in some of the large SMP
systems:
NMI watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [rcuos/1:21]
...
RIP: 0010:[<ffffffff817c216b>] [<ffffffff817c216b>]
_raw_spin_unlock_irqrestore+0x3b/0x60
...
Call Trace:
[<ffffffff813f40d1>] free_object+0x81/0xb0
[<ffffffff813f4f33>] debug_check_no_obj_freed+0x193/0x220
[<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0
[<ffffffff81284996>] ? file_free_rcu+0x36/0x60
[<ffffffff81251712>] kmem_cache_free+0xd2/0x380
[<ffffffff81284960>] ? fput+0x90/0x90
[<ffffffff81284996>] file_free_rcu+0x36/0x60
[<ffffffff81124c23>] rcu_nocb_kthread+0x1b3/0x550
[<ffffffff81124b71>] ? rcu_nocb_kthread+0x101/0x550
[<ffffffff81124a70>] ? sync_exp_work_done.constprop.63+0x50/0x50
[<ffffffff810c59d1>] kthread+0x101/0x120
[<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0
[<ffffffff817c2d32>] ret_from_fork+0x22/0x50
On a 8-socket IvyBridge-EX system (120 cores, 240 threads), the elapsed
time of a 4.9-rc7 kernel parallel build (make -j 240) was reduced from
7m57s to 7m19s with a patched 4.9-rc7 kernel. There was also about a 10X
reduction in the number of debug objects being allocated from or freed to
the kmemcache during the kernel build.
This patch (of 3):
New debugfs stat counters are added to track the numbers of
kmem_cache_alloc() and kmem_cache_free() function calls to get a sense of
how the internal debug objects cache management is performing.
Link: http://lkml.kernel.org/r/1483647425-4135-2-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools')
0 files changed, 0 insertions, 0 deletions