The patch titled
Subject: mm, printk: introduce new format %pGt for page_type
has been added to the -mm mm-unstable branch. Its filename is
mm-printk-introduce-new-format-%pgt-for-page_type.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-printk-introduce-new-format-%pgt-for-page_type.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Subject: mm, printk: introduce new format %pGt for page_type
Date: Mon, 30 Jan 2023 13:25:13 +0900
%pGp format is used to display 'flags' field of a struct page. However,
some page flags (i.e. PG_buddy, see page-flags.h for more details) are
stored in page_type field. To display human-readable output of page_type,
introduce %pGt format.
It is important to note the meaning of bits are different in page_type.
if page_type is 0xffffffff, no flags are set. Setting PG_buddy
(0x00000080) flag results in a page_type of 0xffffff7f. Clearing a bit
actually means setting a flag. Bits in page_type are inverted when
displaying type names.
Only values for which page_type_has_type() returns true are considered as
page_type, to avoid confusion with mapcount values. if it returns false,
only raw values are displayed and not page type names.
Link: https://lkml.kernel.org/r/20230130042514.2418-3-42.hyeyoo@xxxxxxxxx
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: John Ogness <john.ogness@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff --git a/Documentation/core-api/printk-formats.rst~mm-printk-introduce-new-format-%pgt-for-page_type b/Documentation/core-api/printk-formats.rst
--- a/Documentation/core-api/printk-formats.rst~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/Documentation/core-api/printk-formats.rst
@@ -575,20 +575,26 @@ The field width is passed by value, the bitmap is passed by reference.
Helper macros cpumask_pr_args() and nodemask_pr_args() are available to ease
printing cpumask and nodemask.
-Flags bitfields such as page flags, gfp_flags
----------------------------------------------
+Flags bitfields such as page flags, page_type, gfp_flags
+--------------------------------------------------------
::
%pGp 0x17ffffc0002036(referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff)
+ %pGt 0xffffff7f(buddy)
%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.
+character. Currently supported are:
+
+ - p - [p]age flags, expects value of type (``unsigned long *``)
+ - t - page [t]ype, expects value of type (``unsigned int *``)
+ - v - [v]ma_flags, expects value of type (``unsigned long *``)
+ - g - [g]fp_flags, expects value of type (``gfp_t *``)
+
+The flag names and print order depends on the particular type.
Note that this format should not be used directly in the
:c:func:`TP_printk()` part of a tracepoint. Instead, use the show_*_flags()
diff --git a/include/linux/page-flags.h~mm-printk-introduce-new-format-%pgt-for-page_type b/include/linux/page-flags.h
--- a/include/linux/page-flags.h~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/include/linux/page-flags.h
@@ -926,9 +926,14 @@ static inline bool is_page_hwpoison(struct page *page)
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
+static inline int page_type_has_type(unsigned int page_type)
+{
+ return (int)page_type < PAGE_MAPCOUNT_RESERVE;
+}
+
static inline int page_has_type(struct page *page)
{
- return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
+ return page_type_has_type(page->page_type);
}
#define PAGE_TYPE_OPS(uname, lname) \
diff --git a/include/trace/events/mmflags.h~mm-printk-introduce-new-format-%pgt-for-page_type b/include/trace/events/mmflags.h
--- a/include/trace/events/mmflags.h~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/include/trace/events/mmflags.h
@@ -141,6 +141,14 @@ IF_HAVE_PG_SKIP_KASAN_POISON(skip_kasan_poison)
__def_pageflag_names \
) : "none"
+#define DEF_PAGETYPE_NAME(_name) { PG_##_name, __stringify(_name) }
+
+#define __def_pagetype_names \
+ DEF_PAGETYPE_NAME(offline), \
+ DEF_PAGETYPE_NAME(guard), \
+ DEF_PAGETYPE_NAME(table), \
+ DEF_PAGETYPE_NAME(buddy)
+
#if defined(CONFIG_X86)
#define __VM_ARCH_SPECIFIC_1 {VM_PAT, "pat" }
#elif defined(CONFIG_PPC)
diff --git a/lib/test_printf.c~mm-printk-introduce-new-format-%pgt-for-page_type b/lib/test_printf.c
--- a/lib/test_printf.c~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/lib/test_printf.c
@@ -642,12 +642,26 @@ page_flags_test(int section, int node, int zone, int last_cpupid,
test(cmp_buf, "%pGp", &flags);
}
+static void __init page_type_test(unsigned int page_type, const char *name,
+ char *cmp_buf)
+{
+ unsigned long size;
+
+ size = scnprintf(cmp_buf, BUF_SIZE, "%#x(", page_type);
+ if (page_type_has_type(page_type))
+ size += scnprintf(cmp_buf + size, BUF_SIZE - size, "%s", name);
+
+ snprintf(cmp_buf + size, BUF_SIZE - size, ")");
+ test(cmp_buf, "%pGt", &page_type);
+}
+
static void __init
flags(void)
{
unsigned long flags;
char *cmp_buffer;
gfp_t gfp;
+ unsigned int page_type;
cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
if (!cmp_buffer)
@@ -687,6 +701,18 @@ flags(void)
gfp |= __GFP_HIGH;
test(cmp_buffer, "%pGg", &gfp);
+ page_type = ~0;
+ page_type_test(page_type, "", cmp_buffer);
+
+ page_type = 10;
+ page_type_test(page_type, "", cmp_buffer);
+
+ page_type = ~PG_buddy;
+ page_type_test(page_type, "buddy", cmp_buffer);
+
+ page_type = ~(PG_table | PG_buddy);
+ page_type_test(page_type, "table|buddy", cmp_buffer);
+
kfree(cmp_buffer);
}
diff --git a/lib/vsprintf.c~mm-printk-introduce-new-format-%pgt-for-page_type b/lib/vsprintf.c
--- a/lib/vsprintf.c~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/lib/vsprintf.c
@@ -2052,6 +2052,25 @@ char *format_page_flags(char *buf, char *end, unsigned long flags)
return buf;
}
+static
+char *format_page_type(char *buf, char *end, unsigned int page_type)
+{
+ buf = number(buf, end, page_type, default_flag_spec);
+
+ if (buf < end)
+ *buf = '(';
+ buf++;
+
+ if (page_type_has_type(page_type))
+ buf = format_flags(buf, end, ~page_type, pagetype_names);
+
+ if (buf < end)
+ *buf = ')';
+ buf++;
+
+ return buf;
+}
+
static noinline_for_stack
char *flags_string(char *buf, char *end, void *flags_ptr,
struct printf_spec spec, const char *fmt)
@@ -2065,6 +2084,8 @@ char *flags_string(char *buf, char *end, void *flags_ptr,
switch (fmt[1]) {
case 'p':
return format_page_flags(buf, end, *(unsigned long *)flags_ptr);
+ case 't':
+ return format_page_type(buf, end, *(unsigned int *)flags_ptr);
case 'v':
flags = *(unsigned long *)flags_ptr;
names = vmaflag_names;
diff --git a/mm/debug.c~mm-printk-introduce-new-format-%pgt-for-page_type b/mm/debug.c
--- a/mm/debug.c~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/mm/debug.c
@@ -36,6 +36,11 @@ const struct trace_print_flags pageflag_names[] = {
{0, NULL}
};
+const struct trace_print_flags pagetype_names[] = {
+ __def_pagetype_names,
+ {0, NULL}
+};
+
const struct trace_print_flags gfpflag_names[] = {
__def_gfpflag_names,
{0, NULL}
diff --git a/mm/internal.h~mm-printk-introduce-new-format-%pgt-for-page_type b/mm/internal.h
--- a/mm/internal.h~mm-printk-introduce-new-format-%pgt-for-page_type
+++ b/mm/internal.h
@@ -823,6 +823,7 @@ static inline void flush_tlb_batched_pending(struct mm_struct *mm)
#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
extern const struct trace_print_flags pageflag_names[];
+extern const struct trace_print_flags pagetype_names[];
extern const struct trace_print_flags vmaflag_names[];
extern const struct trace_print_flags gfpflag_names[];
_
Patches currently in -mm which might be from 42.hyeyoo@xxxxxxxxx are
mmflagsh-use-less-error-prone-method-to-define-pageflag_names.patch
mm-printk-introduce-new-format-%pgt-for-page_type.patch
mm-debug-use-%pgt-to-display-page_type-in-dump_page.patch
