[PATCH v2 6/9] mm, debug: introduce dump_gfpflag_names() for symbolic printing of gfp_flags

[Vlastimil Babka]

It would be useful to convert gfp_flags into string representation when
printing them in case of allocation failure, OOM etc. There's a script
./scripts/gfp-translate to make this simpler, but it needs the matching version
of the sources to be accurate, and the flags have been undergoing some changes
recently.

The ftrace framework already has this translation in the form of
show_gfp_flags() defined in include/trace/events/gfpflags.h which defines the
translation table internally. Allow reusing the table outside ftrace by putting
it behind __def_gfpflag_names definition and introduce dump_gfpflag_names() to
handle the printing.

While at it, also fill in the names for the flags and flag combinations that
have been missing in the table. GFP_NOWAIT no longer equals to "no flags", so
change the output for no flags to "none".

Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
 include/linux/mmdebug.h         |  1 +
 include/trace/events/gfpflags.h | 14 +++++++++++---
 mm/debug.c                      | 10 ++++++++++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index c447d80..3b77fab 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -10,6 +10,7 @@ struct mm_struct;
 extern void dump_page(struct page *page, const char *reason);
 extern void dump_page_badflags(struct page *page, const char *reason,
 			       unsigned long badflags);
+extern void dump_gfpflag_names(unsigned long gfp_flags);
 void dump_vma(const struct vm_area_struct *vma);
 void dump_mm(const struct mm_struct *mm);
 
diff --git a/include/trace/events/gfpflags.h b/include/trace/events/gfpflags.h
index dde6bf0..3d580fd 100644
--- a/include/trace/events/gfpflags.h
+++ b/include/trace/events/gfpflags.h
@@ -8,8 +8,8 @@
  *
  * Thus most bits set go first.
  */
-#define show_gfp_flags(flags)						\
-	(flags) ? __print_flags(flags, "|",				\
+
+#define __def_gfpflag_names						\
 	{(unsigned long)GFP_TRANSHUGE,		"GFP_TRANSHUGE"},	\
 	{(unsigned long)GFP_HIGHUSER_MOVABLE,	"GFP_HIGHUSER_MOVABLE"}, \
 	{(unsigned long)GFP_HIGHUSER,		"GFP_HIGHUSER"},	\
@@ -19,9 +19,13 @@
 	{(unsigned long)GFP_NOFS,		"GFP_NOFS"},		\
 	{(unsigned long)GFP_ATOMIC,		"GFP_ATOMIC"},		\
 	{(unsigned long)GFP_NOIO,		"GFP_NOIO"},		\
+	{(unsigned long)GFP_NOWAIT,		"GFP_NOWAIT"},		\
+	{(unsigned long)__GFP_DMA,		"GFP_DMA"},		\
+	{(unsigned long)__GFP_DMA32,		"GFP_DMA32"},		\
 	{(unsigned long)__GFP_HIGH,		"GFP_HIGH"},		\
 	{(unsigned long)__GFP_ATOMIC,		"GFP_ATOMIC"},		\
 	{(unsigned long)__GFP_IO,		"GFP_IO"},		\
+	{(unsigned long)__GFP_FS,		"GFP_FS"},		\
 	{(unsigned long)__GFP_COLD,		"GFP_COLD"},		\
 	{(unsigned long)__GFP_NOWARN,		"GFP_NOWARN"},		\
 	{(unsigned long)__GFP_REPEAT,		"GFP_REPEAT"},		\
@@ -36,8 +40,12 @@
 	{(unsigned long)__GFP_RECLAIMABLE,	"GFP_RECLAIMABLE"},	\
 	{(unsigned long)__GFP_MOVABLE,		"GFP_MOVABLE"},		\
 	{(unsigned long)__GFP_NOTRACK,		"GFP_NOTRACK"},		\
+	{(unsigned long)__GFP_WRITE,		"GFP_WRITE"},		\
 	{(unsigned long)__GFP_DIRECT_RECLAIM,	"GFP_DIRECT_RECLAIM"},	\
 	{(unsigned long)__GFP_KSWAPD_RECLAIM,	"GFP_KSWAPD_RECLAIM"},	\
 	{(unsigned long)__GFP_OTHER_NODE,	"GFP_OTHER_NODE"}	\
-	) : "GFP_NOWAIT"
 
+#define show_gfp_flags(flags)						\
+	(flags) ? __print_flags(flags, "|",				\
+	__def_gfpflag_names						\
+	) : "none"
diff --git a/mm/debug.c b/mm/debug.c
index d9718fc..1a71a3b 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -9,6 +9,7 @@
 #include <linux/mm.h>
 #include <linux/trace_events.h>
 #include <linux/memcontrol.h>
+#include <trace/events/gfpflags.h>
 
 static const struct trace_print_flags pageflag_names[] = {
 	{1UL << PG_locked,		"locked"	},
@@ -46,6 +47,10 @@ static const struct trace_print_flags pageflag_names[] = {
 #endif
 };
 
+static const struct trace_print_flags gfpflag_names[] = {
+	__def_gfpflag_names
+};
+
 static void dump_flag_names(unsigned long flags,
 			const struct trace_print_flags *names, int count)
 {
@@ -73,6 +78,11 @@ static void dump_flag_names(unsigned long flags,
 	pr_cont(")\n");
 }
 
+void dump_gfpflag_names(unsigned long gfp_flags)
+{
+	dump_flag_names(gfp_flags, gfpflag_names, ARRAY_SIZE(gfpflag_names));
+}
+
 void dump_page_badflags(struct page *page, const char *reason,
 		unsigned long badflags)
 {
-- 
2.6.3

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