From edf14cdbf9a0e5ab52698ca66d07a76ade0d5c46 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 15 Mar 2016 14:55:56 -0700 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@rasmusvillemoes.dk: lots of good implementation suggestions] Signed-off-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Cc: Rasmus Villemoes Cc: Joonsoo Kim Cc: Minchan Kim Cc: Sasha Levin Cc: "Kirill A. Shutemov" Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/debug.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) (limited to 'mm/debug.c') diff --git a/mm/debug.c b/mm/debug.c index 410af904a7d5..0328fd377545 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -11,12 +11,21 @@ #include #include -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 *page, const char *reason, 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_struct *vma) (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 */ -- cgit v1.2.3-55-g7522