I get below warnning:
BUG: using smp_processor_id() in preemptible [00000000] code: bash/746
caller is native_sched_clock+0x37/0x6e
Pid: 746, comm: bash Tainted: G W 3.0.0+ #254
Call Trace:
[<ffffffff813435c6>] debug_smp_processor_id+0xc2/0xdc
[<ffffffff8104158d>] native_sched_clock+0x37/0x6e
[<ffffffff81116219>] try_to_free_mem_cgroup_pages+0x7d/0x270
[<ffffffff8114f1f8>] mem_cgroup_force_empty+0x24b/0x27a
[<ffffffff8114ff21>] ? sys_close+0x38/0x138
[<ffffffff8114ff21>] ? sys_close+0x38/0x138
[<ffffffff8114f257>] mem_cgroup_force_empty_write+0x17/0x19
[<ffffffff810c72fb>] cgroup_file_write+0xa8/0xba
[<ffffffff811522d2>] vfs_write+0xb3/0x138
[<ffffffff8115241a>] sys_write+0x4a/0x71
[<ffffffff8114ffd9>] ? sys_close+0xf0/0x138
[<ffffffff8176deab>] system_call_fastpath+0x16/0x1b
sched_clock() can't be used with preempt enabled. And we don't
need fast approach to get clock here, so let's use ktime API.
Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7ef6912..22631e0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2283,7 +2283,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
.mem_cgroup = mem,
.memcg_record = rec,
};
- unsigned long start, end;
+ ktime_t start, end;
sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
@@ -2292,7 +2292,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
sc.may_writepage,
sc.gfp_mask);
- start = sched_clock();
+ start = ktime_get();
/*
* NOTE: Although we can get the priority field, using it
* here is not a good idea, since it limits the pages we can scan.
@@ -2301,10 +2301,10 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
* the priority and make it zero.
*/
shrink_zone(0, zone, &sc);
- end = sched_clock();
+ end = ktime_get();
if (rec)
- rec->elapsed += end - start;
+ rec->elapsed += ktime_to_ns(ktime_sub(end, start));
*scanned = sc.nr_scanned;
trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
@@ -2319,7 +2319,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
{
struct zonelist *zonelist;
unsigned long nr_reclaimed;
- unsigned long start, end;
+ ktime_t start, end;
int nid;
struct scan_control sc = {
.may_writepage = !laptop_mode,
@@ -2337,7 +2337,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
.gfp_mask = sc.gfp_mask,
};
- start = sched_clock();
+ start = ktime_get();
/*
* Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't
* take care of from where we get pages. So the node where we start the
@@ -2352,9 +2352,9 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
sc.gfp_mask);
nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
- end = sched_clock();
+ end = ktime_get();
if (rec)
- rec->elapsed += end - start;
+ rec->elapsed += ktime_to_ns(ktime_sub(end, start));
trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
--
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