From 4c85c0be3d7a9a7ffe48bfe0954eacc0ba9d3c75 Mon Sep 17 00:00:00 2001 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> Date: Mon, 30 Jan 2023 13:25:13 +0900 Subject: 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 [vsprintf part] Cc: Andy Shevchenko Cc: David Hildenbrand Cc: Joe Perches Cc: John Ogness Cc: Matthew Wilcox Cc: Sergey Senozhatsky Cc: Steven Rostedt (Google) Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/core-api/printk-formats.rst | 16 +++++++++++----- include/linux/page-flags.h | 7 ++++++- include/trace/events/mmflags.h | 8 ++++++++ lib/test_printf.c | 26 ++++++++++++++++++++++++++ lib/vsprintf.c | 21 +++++++++++++++++++++ mm/debug.c | 5 +++++ mm/internal.h | 1 + 7 files changed, 78 insertions(+), 6 deletions(-) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index dbe1aacc79d0..dfe7e75a71de 100644 --- a/Documentation/core-api/printk-formats.rst +++ 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 b/include/linux/page-flags.h index a7e3a3405520..57287102c5bd 100644 --- a/include/linux/page-flags.h +++ 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 b/include/trace/events/mmflags.h index f453babe29b3..b28218b7998e 100644 --- a/include/trace/events/mmflags.h +++ 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 b/lib/test_printf.c index 46b4e6c414a3..7677ebccf3c3 100644 --- a/lib/test_printf.c +++ 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 b/lib/vsprintf.c index be71a03c936a..fbe320b5e89f 100644 --- a/lib/vsprintf.c +++ 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 b/mm/debug.c index 96d594e16292..01cf0435723b 100644 --- a/mm/debug.c +++ 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 b/mm/internal.h index 7920a8b7982e..2a7ffd9962c4 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -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[]; -- cgit