The patch titled
Subject: tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix
has been added to the -mm tree. Its filename is
tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix.patch
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------------------------------------------------------
From: "Shreyas B. Prabhu" <shreyas@xxxxxxxxxxxxxxxxxx>
Subject: tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix
use raw_smp_processor_id()
Cc: Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/trace/events/kmem.h | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff -puN include/trace/events/kmem.h~tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix include/trace/events/kmem.h
--- a/include/trace/events/kmem.h~tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix
+++ a/include/trace/events/kmem.h
@@ -146,7 +146,16 @@ DEFINE_EVENT_CONDITION(kmem_free, kmem_c
TP_ARGS(call_site, ptr),
- TP_CONDITION(cpu_online(smp_processor_id()))
+ /*
+ * This trace can be potentially called from an offlined cpu.
+ * Since trace points use RCU and RCU should not be used from
+ * offline cpus, filter such calls out.
+ * While this trace can be called from a preemptable section,
+ * it has no impact on the condition since tasks can migrate
+ * only from online cpus to other online cpus. Thus its safe
+ * to use raw_smp_processor_id.
+ */
+ TP_CONDITION(cpu_online(raw_smp_processor_id()))
);
TRACE_EVENT(mm_page_free,
_
Patches currently in -mm which might be from shreyas@xxxxxxxxxxxxxxxxxx are
tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus.patch
tracing-mm-dont-trace-kmem_cache_free-on-offline-cpus-fix.patch
tracing-mm-dont-trace-mm_page_free-on-offline-cpus.patch
tracing-mm-dont-trace-mm_page_free-on-offline-cpus-fix.patch
tracing-mm-dont-trace-mm_page_pcpu_drain-on-offline-cpus.patch
tracing-mm-dont-trace-mm_page_pcpu_drain-on-offline-cpus-fix.patch
a.patch
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