tracing: add trace event for memory-failure

RAS user space tools like rasdaemon which base on trace event, could
receive mce error event, but no memory recovery result event. So, I want
to add this event to make this scenario complete.

This patch add a event at ras group for memory-failure.

The output like below:
# tracer: nop
#
# entries-in-buffer/entries-written: 2/2 #P:24
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
mce-inject-13150 [001] .... 277.019359: memory_failure_event: pfn 0x19869: recovery action for free buddy page: Delayed

[[e-mail]: fix build error]
Signed-off-by: Xie XiuQi <[e-mail]>
Reviewed-by: Naoya Horiguchi <[e-mail]>
Acked-by: Steven Rostedt <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Chen Gong <[e-mail]>
Cc: Jim Davis <[e-mail]>
Signed-off-by: Xie XiuQi <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/ras/ras_event.h

···
 #include <linux/pci.h>
 #include <linux/aer.h>
 #include <linux/cper.h>
+#include <linux/mm.h>
 
 /*
  * MCE Extended Error Log trace event
···
 		__print_flags(__entry->status, "|", aer_uncorrectable_errors))
 );
 
+/*
+ * memory-failure recovery action result event
+ *
+ * unsigned long pfn -	Page Frame Number of the corrupted page
+ * int type	-	Page types of the corrupted page
+ * int result	-	Result of recovery action
+ */
+
+#ifdef CONFIG_MEMORY_FAILURE
+#define MF_ACTION_RESULT	\
+	EM ( MF_IGNORED, "Ignored" )	\
+	EM ( MF_FAILED,  "Failed" )	\
+	EM ( MF_DELAYED, "Delayed" )	\
+	EMe ( MF_RECOVERED, "Recovered" )
+
+#define MF_PAGE_TYPE		\
+	EM ( MF_MSG_KERNEL, "reserved kernel page" )			\
+	EM ( MF_MSG_KERNEL_HIGH_ORDER, "high-order kernel page" )	\
+	EM ( MF_MSG_SLAB, "kernel slab page" )				\
+	EM ( MF_MSG_DIFFERENT_COMPOUND, "different compound page after locking" ) \
+	EM ( MF_MSG_POISONED_HUGE, "huge page already hardware poisoned" )	\
+	EM ( MF_MSG_HUGE, "huge page" )					\
+	EM ( MF_MSG_FREE_HUGE, "free huge page" )			\
+	EM ( MF_MSG_UNMAP_FAILED, "unmapping failed page" )		\
+	EM ( MF_MSG_DIRTY_SWAPCACHE, "dirty swapcache page" )		\
+	EM ( MF_MSG_CLEAN_SWAPCACHE, "clean swapcache page" )		\
+	EM ( MF_MSG_DIRTY_MLOCKED_LRU, "dirty mlocked LRU page" )	\
+	EM ( MF_MSG_CLEAN_MLOCKED_LRU, "clean mlocked LRU page" )	\
+	EM ( MF_MSG_DIRTY_UNEVICTABLE_LRU, "dirty unevictable LRU page" )	\
+	EM ( MF_MSG_CLEAN_UNEVICTABLE_LRU, "clean unevictable LRU page" )	\
+	EM ( MF_MSG_DIRTY_LRU, "dirty LRU page" )			\
+	EM ( MF_MSG_CLEAN_LRU, "clean LRU page" )			\
+	EM ( MF_MSG_TRUNCATED_LRU, "already truncated LRU page" )	\
+	EM ( MF_MSG_BUDDY, "free buddy page" )				\
+	EM ( MF_MSG_BUDDY_2ND, "free buddy page (2nd try)" )		\
+	EMe ( MF_MSG_UNKNOWN, "unknown page" )
+
+/*
+ * First define the enums in MM_ACTION_RESULT to be exported to userspace
+ * via TRACE_DEFINE_ENUM().
+ */
+#undef EM
+#undef EMe
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+MF_ACTION_RESULT
+MF_PAGE_TYPE
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)		{ a, b },
+#define EMe(a, b)	{ a, b }
+
+TRACE_EVENT(memory_failure_event,
+	TP_PROTO(unsigned long pfn,
+		 int type,
+		 int result),
+
+	TP_ARGS(pfn, type, result),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, pfn)
+		__field(int, type)
+		__field(int, result)
+	),
+
+	TP_fast_assign(
+		__entry->pfn	= pfn;
+		__entry->type	= type;
+		__entry->result	= result;
+	),
+
+	TP_printk("pfn %#lx: recovery action for %s: %s",
+		__entry->pfn,
+		__print_symbolic(__entry->type, MF_PAGE_TYPE),
+		__print_symbolic(__entry->result, MF_ACTION_RESULT)
+	)
+);
+#endif /* CONFIG_MEMORY_FAILURE */
 #endif /* _TRACE_HW_EVENT_MC_H */
 
 /* This part must be outside protection */

mm/Kconfig

···
 	depends on ARCH_SUPPORTS_MEMORY_FAILURE
 	bool "Enable recovery from hardware memory errors"
 	select MEMORY_ISOLATION
+	select RAS
 	help
 	  Enables code to recover from some memory failures on systems
 	  with MCA recovery. This allows a system to continue running

mm/memory-failure.c

···
 #include <linux/mm_inline.h>
 #include <linux/kfifo.h>
 #include "internal.h"
+#include "ras/ras_event.h"
 
 int sysctl_memory_failure_early_kill __read_mostly = 0;
 
···
 static void action_result(unsigned long pfn, enum mf_action_page_type type,
 			  enum mf_result result)
 {
+	trace_memory_failure_event(pfn, type, result);
+
 	pr_err("MCE %#lx: recovery action for %s: %s\n",
 		pfn, action_page_types[type], action_name[result]);
 }