Re: [PATCH] mm/debug: sync up latest migrate_reason to migrate_reason_names

From: John Hubbard
Date: Sun Sep 19 2021 - 02:41:53 EST


On 9/18/21 00:03, Weizhao Ouyang wrote:
...
Anyway, I didn't find a simply way the build the "everywhere" relationship behind
the packaged TRACE_DEFINE_ENUM , what do you think.

It's actually pretty easy, unless I'm unknowingly violating some rule
here. But I did review tracing a bit before diving in, and I think this
is reasonable.

The trace macros EM(), EMe(), and MIGRATE_REASON are flexible enough to
get whatever you want, out of them. So, the trace header can be the one
location for the definition of the enum-to-string mapping.

The key is to move the enum to a common header file that both the trace
system (trace/events/migrate.h) and the migrate header
(include/linux/migrate.h) can include. Fortunately, that's already been
started for enum migrate_mode: there is migrate_mode.h.

So it all works approximately like this, below. (I'll attach a
white-space-correct diff that you can apply directly, too). I've
compiled tested and rebooted with it, but haven't checked much more
than that yet.

---
include/linux/migrate.h | 16 ++--------------
include/linux/migrate_mode.h | 13 +++++++++++++
mm/debug.c | 19 ++++++++++++-------
3 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 326250996b4e..cb62fbc3d8d6 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -6,6 +6,7 @@
#include <linux/mempolicy.h>
#include <linux/migrate_mode.h>
#include <linux/hugetlb.h>
+#include <linux/migrate_mode.h>

typedef struct page *new_page_t(struct page *page, unsigned long private);
typedef void free_page_t(struct page *page, unsigned long private);
@@ -19,20 +20,7 @@ struct migration_target_control;
*/
#define MIGRATEPAGE_SUCCESS 0

-enum migrate_reason {
- MR_COMPACTION,
- MR_MEMORY_FAILURE,
- MR_MEMORY_HOTPLUG,
- MR_SYSCALL, /* also applies to cpusets */
- MR_MEMPOLICY_MBIND,
- MR_NUMA_MISPLACED,
- MR_CONTIG_RANGE,
- MR_LONGTERM_PIN,
- MR_DEMOTION,
- MR_TYPES
-};
-
-/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
+/* In mm/debug.c */
extern const char *migrate_reason_names[MR_TYPES];

#ifdef CONFIG_MIGRATION
diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h
index 883c99249033..f37cc03f9369 100644
--- a/include/linux/migrate_mode.h
+++ b/include/linux/migrate_mode.h
@@ -19,4 +19,17 @@ enum migrate_mode {
MIGRATE_SYNC_NO_COPY,
};

+enum migrate_reason {
+ MR_COMPACTION,
+ MR_MEMORY_FAILURE,
+ MR_MEMORY_HOTPLUG,
+ MR_SYSCALL, /* also applies to cpusets */
+ MR_MEMPOLICY_MBIND,
+ MR_NUMA_MISPLACED,
+ MR_CONTIG_RANGE,
+ MR_LONGTERM_PIN,
+ MR_DEMOTION,
+ MR_TYPES
+};
+
#endif /* MIGRATE_MODE_H_INCLUDED */
diff --git a/mm/debug.c b/mm/debug.c
index e73fe0a8ec3d..51152ffc1f29 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -17,14 +17,19 @@

#include "internal.h"

+#include <trace/events/migrate.h>
+
+/*
+ * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can
+ * be used to populate migrate_reason_names[].
+ */
+#undef EM
+#undef EMe
+#define EM(a, b) b,
+#define EMe(a, b) b
+
const char *migrate_reason_names[MR_TYPES] = {
- "compaction",
- "memory_failure",
- "memory_hotplug",
- "syscall_or_cpuset",
- "mempolicy_mbind",
- "numa_misplaced",
- "cma",
+ MIGRATE_REASON
};

const struct trace_print_flags pageflag_names[] = {
--
2.33.0

thanks,
--
John Hubbard
NVIDIAFrom 7b10419a1de9be352539b38e2ca70cc5b14687d9 Mon Sep 17 00:00:00 2001
From: John Hubbard <jhubbard@xxxxxxxxxx>
Date: Sat, 18 Sep 2021 22:07:20 -0700
Subject: [PATCH] Use one definition of MIGRATE_REASON strings, everywhere
X-NVConfidentiality: public
Cc: John Hubbard <jhubbard@xxxxxxxxxx>

(Compiled-tested only, so no signed off by tag.)
---
include/linux/migrate.h | 16 ++--------------
include/linux/migrate_mode.h | 13 +++++++++++++
mm/debug.c | 19 ++++++++++++-------
3 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 326250996b4e..cb62fbc3d8d6 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -6,6 +6,7 @@
#include <linux/mempolicy.h>
#include <linux/migrate_mode.h>
#include <linux/hugetlb.h>
+#include <linux/migrate_mode.h>

typedef struct page *new_page_t(struct page *page, unsigned long private);
typedef void free_page_t(struct page *page, unsigned long private);
@@ -19,20 +20,7 @@ struct migration_target_control;
*/
#define MIGRATEPAGE_SUCCESS 0

-enum migrate_reason {
- MR_COMPACTION,
- MR_MEMORY_FAILURE,
- MR_MEMORY_HOTPLUG,
- MR_SYSCALL, /* also applies to cpusets */
- MR_MEMPOLICY_MBIND,
- MR_NUMA_MISPLACED,
- MR_CONTIG_RANGE,
- MR_LONGTERM_PIN,
- MR_DEMOTION,
- MR_TYPES
-};
-
-/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
+/* In mm/debug.c */
extern const char *migrate_reason_names[MR_TYPES];

#ifdef CONFIG_MIGRATION
diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h
index 883c99249033..f37cc03f9369 100644
--- a/include/linux/migrate_mode.h
+++ b/include/linux/migrate_mode.h
@@ -19,4 +19,17 @@ enum migrate_mode {
MIGRATE_SYNC_NO_COPY,
};

+enum migrate_reason {
+ MR_COMPACTION,
+ MR_MEMORY_FAILURE,
+ MR_MEMORY_HOTPLUG,
+ MR_SYSCALL, /* also applies to cpusets */
+ MR_MEMPOLICY_MBIND,
+ MR_NUMA_MISPLACED,
+ MR_CONTIG_RANGE,
+ MR_LONGTERM_PIN,
+ MR_DEMOTION,
+ MR_TYPES
+};
+
#endif /* MIGRATE_MODE_H_INCLUDED */
diff --git a/mm/debug.c b/mm/debug.c
index e73fe0a8ec3d..51152ffc1f29 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -17,14 +17,19 @@

#include "internal.h"

+#include <trace/events/migrate.h>
+
+/*
+ * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can
+ * be used to populate migrate_reason_names[].
+ */
+#undef EM
+#undef EMe
+#define EM(a, b) b,
+#define EMe(a, b) b
+
const char *migrate_reason_names[MR_TYPES] = {
- "compaction",
- "memory_failure",
- "memory_hotplug",
- "syscall_or_cpuset",
- "mempolicy_mbind",
- "numa_misplaced",
- "cma",
+ MIGRATE_REASON
};

const struct trace_print_flags pageflag_names[] = {
--
2.33.0