#include "tests.h"
#include "machine.h"
#include "thread.h"
#include "map.h"
#include "debug.h"
int test__thread_mg_share(int subtest __maybe_unused)
{
struct machines machines;
struct machine *machine;
/* thread group */
struct thread *leader;
struct thread *t1, *t2, *t3;
struct map_groups *mg;
/* other process */
struct thread *other, *other_leader;
struct map_groups *other_mg;
/*
* This test create 2 processes abstractions (struct thread)
* with several threads and checks they properly share and
* maintain map groups info (struct map_groups).
*
* thread group (pid: 0, tids: 0, 1, 2, 3)
* other group (pid: 4, tids: 4, 5)
*/
machines__init(&machines);
machine = &machines.host;
/* create process with 4 threads */
leader = machine__findnew_thread(machine, 0, 0);
t1 = machine__findnew_thread(machine, 0, 1);
t2 = machine__findnew_thread(machine, 0, 2);
t3 = machine__findnew_thread(machine, 0, 3);
/* and create 1 separated process, without thread leader */
other = machine__findnew_thread(machine, 4, 5);
TEST_ASSERT_VAL("failed to create threads",
leader && t1 && t2 && t3 && other);
mg = leader->mg;
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 4);
/* test the map groups pointer is shared */
TEST_ASSERT_VAL("map groups don't match", mg == t1->mg);
TEST_ASSERT_VAL("map groups don't match", mg == t2->mg);
TEST_ASSERT_VAL("map groups don't match", mg == t3->mg);
/*
* Verify the other leader was created by previous call.
* It should have shared map groups with no change in
* refcnt.
*/
other_leader = machine__find_thread(machine, 4, 4);
TEST_ASSERT_VAL("failed to find other leader", other_leader);
/*
* Ok, now that all the rbtree related operations were done,
* lets remove all of them from there so that we can do the
* refcounting tests.
*/
machine__remove_thread(machine, leader);
machine__remove_thread(machine, t1);
machine__remove_thread(machine, t2);
machine__remove_thread(machine, t3);
machine__remove_thread(machine, other);
machine__remove_thread(machine, other_leader);
other_mg = other->mg;
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&other_mg->refcnt), 2);
TEST_ASSERT_VAL("map groups don't match", other_mg == other_leader->mg);
/* release thread group */
thread__put(leader);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 3);
thread__put(t1);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 2);
thread__put(t2);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 1);
thread__put(t3);
/* release other group */
thread__put(other_leader);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&other_mg->refcnt), 1);
thread__put(other);
machines__exit(&machines);
return 0;
}
aa534'>ipc/msgutil.c
mm/slab: improve performance of gathering slabinfo stats
On large systems, when some slab caches grow to millions of objects (and
many gigabytes), running 'cat /proc/slabinfo' can take up to 1-2
seconds. During this time, interrupts are disabled while walking the
slab lists (slabs_full, slabs_partial, and slabs_free) for each node,
and this sometimes causes timeouts in other drivers (for instance,
Infiniband).
This patch optimizes 'cat /proc/slabinfo' by maintaining a counter for
total number of allocated slabs per node, per cache. This counter is
updated when a slab is created or destroyed. This enables us to skip
traversing the slabs_full list while gathering slabinfo statistics, and
since slabs_full tends to be the biggest list when the cache is large,
it results in a dramatic performance improvement. Getting slabinfo
statistics now only requires walking the slabs_free and slabs_partial
lists, and those lists are usually much smaller than slabs_full.
We tested this after growing the dentry cache to 70GB, and the
performance improved from 2s to 5ms.
Link: http://lkml.kernel.org/r/1472517876-26814-1-git-send-email-aruna.ramakrishna@oracle.com
Signed-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>