sched/membarrier: reduce the ability to hammer on sys_membarrier
commit 944d5fe50f3f03daacfea16300e656a1691c4a23 upstream.
On some systems, sys_membarrier can be very expensive, causing overall
slowdowns for everything. So put a lock on the path in order to
serialize the accesses to prevent the ability for this to be called at
too high of a frequency and saturate the machine.
Reviewed-and-tested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Fixes: 22e4ebb97582 ("membarrier: Provide expedited private command")
Fixes: c5f58bd58f43 ("membarrier: Provide GLOBAL_EXPEDITED command")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ converted to explicit mutex_*() calls - cleanup.h is not in this stable
branch - gregkh ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 3cd139875e9a7688b3fc715264032620812a5fa3)
[vegard: fixed conflict due to missing commit
c5f58bd58f432be5d92df33c5458e0bcbee3aadf ("membarrier: Provide
GLOBAL_EXPEDITED command")]
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
1 file changed