mm, printk: introduce new format %pGt for page_type

%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@gmail.com
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>	[vsprintf part]
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Hyeonggon Yoo 2023-01-30 13:25:13 +09:00 committed by Andrew Morton
parent e26fcc02c7
commit 4c85c0be3d
7 changed files with 78 additions and 6 deletions

View File

@ -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()

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@ -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) \

View File

@ -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)

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@ -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);
}

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@ -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;

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@ -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}

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@ -802,6 +802,7 @@ 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[];