The patch titled
Subject: mm, printk: introduce new format string for flags
has been added to the -mm tree. Its filename is
mm-printk-introduce-new-format-string-for-flags.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-printk-introduce-new-format-string-for-flags.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-printk-introduce-new-format-string-for-flags.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, printk: introduce new format string for flags
In mm we use several kinds of flags bitfields that are sometimes printed
for debugging purposes, or exported to userspace via sysfs. To make them
easier to interpret independently on kernel version and config, we want to
dump also the symbolic flag names. So far this has been done with
repeated calls to pr_cont(), which is unreliable on SMP, and not usable
for e.g. sysfs export.
To get a more reliable and universal solution, this patch extends printk()
format string for pointers to handle the page flags (%pGp), gfp_flags
(%pGg) and vma flags (%pGv). Existing users of dump_flag_names() are
converted and simplified.
It would be possible to pass flags by value instead of pointer, but the %p
format string for pointers already has extensions for various kernel
structures, so it's a good fit, and the extra indirection in a
non-critical path is negligible.
[linux@xxxxxxxxxxxxxxxxxx: lots of good implementation suggestions]
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/printk-formats.txt | 18 ++++++
include/linux/mmdebug.h | 6 ++
lib/test_printf.c | 53 ++++++++++++++++++++
lib/vsprintf.c | 75 +++++++++++++++++++++++++++++
mm/debug.c | 34 +++++++------
mm/internal.h | 6 ++
6 files changed, 178 insertions(+), 14 deletions(-)
diff -puN Documentation/printk-formats.txt~mm-printk-introduce-new-format-string-for-flags Documentation/printk-formats.txt
--- a/Documentation/printk-formats.txt~mm-printk-introduce-new-format-string-for-flags
+++ a/Documentation/printk-formats.txt
@@ -298,6 +298,24 @@ bitmap and its derivatives such as cpuma
Passed by reference.
+Flags bitfields such as page flags, gfp_flags:
+
+ %pGp referenced|uptodate|lru|active|private
+ %pGg GFP_USER|GFP_DMA32|GFP_NOWARN
+ %pGv read|exec|mayread|maywrite|mayexec|denywrite
+
+ For printing flags bitfields as a collection of symbolic constants that
+ would construct the value. The type of flags is given by the third
+ character. Currently supported are [p]age flags, [v]ma_flags (both
+ expect unsigned long *) and [g]fp_flags (expects gfp_t *). The flag
+ names and print order depends on the particular type.
+
+ Note that this format should not be used directly in TP_printk() part
+ of a tracepoint. Instead, use the show_*_flags() functions from
+ <trace/events/mmflags.h>.
+
+ Passed by reference.
+
Network device features:
%pNF 0x000000000000c000
diff -puN include/linux/mmdebug.h~mm-printk-introduce-new-format-string-for-flags include/linux/mmdebug.h
--- a/include/linux/mmdebug.h~mm-printk-introduce-new-format-string-for-flags
+++ a/include/linux/mmdebug.h
@@ -3,11 +3,17 @@
#include <linux/bug.h>
#include <linux/stringify.h>
+#include <linux/types.h>
+#include <linux/tracepoint.h>
struct page;
struct vm_area_struct;
struct mm_struct;
+extern const struct trace_print_flags pageflag_names[];
+extern const struct trace_print_flags vmaflag_names[];
+extern const struct trace_print_flags gfpflag_names[];
+
extern void dump_page(struct page *page, const char *reason);
extern void dump_page_badflags(struct page *page, const char *reason,
unsigned long badflags);
diff -puN lib/test_printf.c~mm-printk-introduce-new-format-string-for-flags lib/test_printf.c
--- a/lib/test_printf.c~mm-printk-introduce-new-format-string-for-flags
+++ a/lib/test_printf.c
@@ -17,6 +17,9 @@
#include <linux/socket.h>
#include <linux/in.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+
#define BUF_SIZE 256
#define PAD_SIZE 16
#define FILL_CHAR '$'
@@ -411,6 +414,55 @@ netdev_features(void)
}
static void __init
+flags(void)
+{
+ unsigned long flags;
+ gfp_t gfp;
+ char *cmp_buffer;
+
+ flags = 0;
+ test("", "%pGp", &flags);
+
+ /* Page flags should filter the zone id */
+ flags = 1UL << NR_PAGEFLAGS;
+ test("", "%pGp", &flags);
+
+ flags |= 1UL << PG_uptodate | 1UL << PG_dirty | 1UL << PG_lru
+ | 1UL << PG_active | 1UL << PG_swapbacked;
+ test("uptodate|dirty|lru|active|swapbacked", "%pGp", &flags);
+
+
+ flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC
+ | VM_DENYWRITE;
+ test("read|exec|mayread|maywrite|mayexec|denywrite", "%pGv", &flags);
+
+ gfp = GFP_TRANSHUGE;
+ test("GFP_TRANSHUGE", "%pGg", &gfp);
+
+ gfp = GFP_ATOMIC|__GFP_DMA;
+ test("GFP_ATOMIC|GFP_DMA", "%pGg", &gfp);
+
+ gfp = __GFP_ATOMIC;
+ test("__GFP_ATOMIC", "%pGg", &gfp);
+
+ cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
+ if (!cmp_buffer)
+ return;
+
+ /* Any flags not translated by the table should remain numeric */
+ gfp = ~__GFP_BITS_MASK;
+ snprintf(cmp_buffer, BUF_SIZE, "%#lx", (unsigned long) gfp);
+ test(cmp_buffer, "%pGg", &gfp);
+
+ snprintf(cmp_buffer, BUF_SIZE, "__GFP_ATOMIC|%#lx",
+ (unsigned long) gfp);
+ gfp |= __GFP_ATOMIC;
+ test(cmp_buffer, "%pGg", &gfp);
+
+ kfree(cmp_buffer);
+}
+
+static void __init
test_pointer(void)
{
plain();
@@ -428,6 +480,7 @@ test_pointer(void)
struct_clk();
bitmap();
netdev_features();
+ flags();
}
static int __init
diff -puN lib/vsprintf.c~mm-printk-introduce-new-format-string-for-flags lib/vsprintf.c
--- a/lib/vsprintf.c~mm-printk-introduce-new-format-string-for-flags
+++ a/lib/vsprintf.c
@@ -35,6 +35,8 @@
#include <linux/blkdev.h>
#endif
+#include "../mm/internal.h" /* For the trace_print_flags arrays */
+
#include <asm/page.h> /* for PAGE_SIZE */
#include <asm/sections.h> /* for dereference_function_descriptor() */
#include <asm/byteorder.h> /* cpu_to_le16 */
@@ -1407,6 +1409,72 @@ char *clock(char *buf, char *end, struct
}
}
+static
+char *format_flags(char *buf, char *end, unsigned long flags,
+ const struct trace_print_flags *names)
+{
+ unsigned long mask;
+ const struct printf_spec strspec = {
+ .field_width = -1,
+ .precision = -1,
+ };
+ const struct printf_spec numspec = {
+ .flags = SPECIAL|SMALL,
+ .field_width = -1,
+ .precision = -1,
+ .base = 16,
+ };
+
+ for ( ; flags && names->name; names++) {
+ mask = names->mask;
+ if ((flags & mask) != mask)
+ continue;
+
+ buf = string(buf, end, names->name, strspec);
+
+ flags &= ~mask;
+ if (flags) {
+ if (buf < end)
+ *buf = '|';
+ buf++;
+ }
+ }
+
+ if (flags)
+ buf = number(buf, end, flags, numspec);
+
+ return buf;
+}
+
+static noinline_for_stack
+char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
+{
+ unsigned long flags;
+ const struct trace_print_flags *names;
+
+ switch (fmt[1]) {
+ case 'p':
+ flags = *(unsigned long *)flags_ptr;
+ /* Remove zone id */
+ flags &= (1UL << NR_PAGEFLAGS) - 1;
+ names = pageflag_names;
+ break;
+ case 'v':
+ flags = *(unsigned long *)flags_ptr;
+ names = vmaflag_names;
+ break;
+ case 'g':
+ flags = *(gfp_t *)flags_ptr;
+ names = gfpflag_names;
+ break;
+ default:
+ WARN_ONCE(1, "Unsupported flags modifier: %c\n", fmt[1]);
+ return buf;
+ }
+
+ return format_flags(buf, end, flags, names);
+}
+
int kptr_restrict __read_mostly;
/*
@@ -1495,6 +1563,11 @@ int kptr_restrict __read_mostly;
* - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
* (legacy clock framework) of the clock
* - 'Cr' For a clock, it prints the current rate of the clock
+ * - 'G' For flags to be printed as a collection of symbolic strings that would
+ * construct the specific value. Supported flags given by option:
+ * p page flags (see struct page) given as pointer to unsigned long
+ * g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
+ * v vma flags (VM_*) given as pointer to unsigned long
*
* ** Please update also Documentation/printk-formats.txt when making changes **
*
@@ -1648,6 +1721,8 @@ char *pointer(const char *fmt, char *buf
return bdev_name(buf, end, ptr, spec, fmt);
#endif
+ case 'G':
+ return flags_string(buf, end, ptr, fmt);
}
spec.flags |= SMALL;
if (spec.field_width == -1) {
diff -puN mm/debug.c~mm-printk-introduce-new-format-string-for-flags mm/debug.c
--- a/mm/debug.c~mm-printk-introduce-new-format-string-for-flags
+++ a/mm/debug.c
@@ -11,12 +11,21 @@
#include <linux/memcontrol.h>
#include <trace/events/mmflags.h>
-static const struct trace_print_flags pageflag_names[] = {
- __def_pageflag_names
+#include "internal.h"
+
+const struct trace_print_flags pageflag_names[] = {
+ __def_pageflag_names,
+ {0, NULL}
+};
+
+const struct trace_print_flags gfpflag_names[] = {
+ __def_gfpflag_names,
+ {0, NULL}
};
-static const struct trace_print_flags gfpflag_names[] = {
- __def_gfpflag_names
+const struct trace_print_flags vmaflag_names[] = {
+ __def_vmaflag_names,
+ {0, NULL}
};
static void dump_flags(unsigned long flags,
@@ -58,14 +67,15 @@ void dump_page_badflags(struct page *pag
if (PageCompound(page))
pr_cont(" compound_mapcount: %d", compound_mapcount(page));
pr_cont("\n");
- BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);
- dump_flags(page->flags, pageflag_names, ARRAY_SIZE(pageflag_names));
+ BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
+ dump_flags(page->flags, pageflag_names,
+ ARRAY_SIZE(pageflag_names) - 1);
if (reason)
pr_alert("page dumped because: %s\n", reason);
if (page->flags & badflags) {
pr_alert("bad because of flags:\n");
- dump_flags(page->flags & badflags,
- pageflag_names, ARRAY_SIZE(pageflag_names));
+ dump_flags(page->flags & badflags, pageflag_names,
+ ARRAY_SIZE(pageflag_names) - 1);
}
#ifdef CONFIG_MEMCG
if (page->mem_cgroup)
@@ -81,10 +91,6 @@ EXPORT_SYMBOL(dump_page);
#ifdef CONFIG_DEBUG_VM
-static const struct trace_print_flags vmaflag_names[] = {
- __def_vmaflag_names
-};
-
void dump_vma(const struct vm_area_struct *vma)
{
pr_emerg("vma %p start %p end %p\n"
@@ -96,7 +102,7 @@ void dump_vma(const struct vm_area_struc
(unsigned long)pgprot_val(vma->vm_page_prot),
vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
vma->vm_file, vma->vm_private_data);
- dump_flags(vma->vm_flags, vmaflag_names, ARRAY_SIZE(vmaflag_names));
+ dump_flags(vma->vm_flags, vmaflag_names, ARRAY_SIZE(vmaflag_names) - 1);
}
EXPORT_SYMBOL(dump_vma);
@@ -168,7 +174,7 @@ void dump_mm(const struct mm_struct *mm)
);
dump_flags(mm->def_flags, vmaflag_names,
- ARRAY_SIZE(vmaflag_names));
+ ARRAY_SIZE(vmaflag_names) - 1);
}
#endif /* CONFIG_DEBUG_VM */
diff -puN mm/internal.h~mm-printk-introduce-new-format-string-for-flags mm/internal.h
--- a/mm/internal.h~mm-printk-introduce-new-format-string-for-flags
+++ a/mm/internal.h
@@ -14,6 +14,7 @@
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
+#include <linux/tracepoint-defs.h>
/*
* The set of flags that only affect watermark checking and reclaim
@@ -435,4 +436,9 @@ static inline void try_to_unmap_flush_di
}
#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
+
+extern const struct trace_print_flags pageflag_names[];
+extern const struct trace_print_flags vmaflag_names[];
+extern const struct trace_print_flags gfpflag_names[];
+
#endif /* __MM_INTERNAL_H */
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
tracepoints-move-trace_print_flags-definitions-to-tracepoint-defsh.patch
mm-tracing-make-show_gfp_flags-up-to-date.patch
tools-perf-make-gfp_compact_table-up-to-date.patch
mm-tracing-unify-mm-flags-handling-in-tracepoints-and-printk.patch
mm-printk-introduce-new-format-string-for-flags.patch
mm-debug-replace-dump_flags-with-the-new-printk-formats.patch
mm-page_alloc-print-symbolic-gfp_flags-on-allocation-failure.patch
mm-oom-print-symbolic-gfp_flags-in-oom-warning.patch
mm-page_owner-print-migratetype-of-page-and-pageblock-symbolic-flags.patch
mm-page_owner-convert-page_owner_inited-to-static-key.patch
mm-page_owner-copy-page-owner-info-during-migration.patch
mm-page_owner-track-and-print-last-migrate-reason.patch
mm-page_owner-dump-page-owner-info-from-dump_page.patch
mm-debug-move-bad-flags-printing-to-bad_page.patch
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