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mm: introduce dump_vma
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Introduce a helper to dump information about a VMA, this also makes
dump_page_flags more generic and re-uses that so the output looks very
similar to dump_page:

[   61.903437] vma ffff88070f88be00 start 00007fff25970000 end 00007fff25992000
[   61.903437] next ffff88070facd600 prev ffff88070face400 mm ffff88070fade000
[   61.903437] prot 8000000000000025 anon_vma ffff88070fa1e200 vm_ops           (null)
[   61.903437] pgoff 7ffffffdd file           (null) private_data           (null)
[   61.909129] flags: 0x100173(read|write|mayread|maywrite|mayexec|growsdown|account)

[[email protected]: make dump_vma() require CONFIG_DEBUG_VM]
[[email protected]: fix dump_vma() compilation]
Signed-off-by: Sasha Levin <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Minchan Kim <[email protected]>
Signed-off-by: Stephen Warren <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@sashalevin @torvalds
sashalevin authored and torvalds committed Oct 10, 2014
1 parent b208ce3 commit 0bf5513
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Showing 2 changed files with 75 additions and 9 deletions.
2 changes: 2 additions & 0 deletions include/linux/mmdebug.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4,10 +4,12 @@
#include <linux/stringify.h>

struct page;
struct vm_area_struct;

extern void dump_page(struct page *page, const char *reason);
extern void dump_page_badflags(struct page *page, const char *reason,
unsigned long badflags);
void dump_vma(const struct vm_area_struct *vma);

#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
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82 changes: 73 additions & 9 deletions mm/page_alloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6626,27 +6626,26 @@ static const struct trace_print_flags pageflag_names[] = {
#endif
};

static void dump_page_flags(unsigned long flags)
static void dump_flags(unsigned long flags,
const struct trace_print_flags *names, int count)
{
const char *delim = "";
unsigned long mask;
int i;

BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);

printk(KERN_ALERT "page flags: %#lx(", flags);
printk(KERN_ALERT "flags: %#lx(", flags);

/* remove zone id */
flags &= (1UL << NR_PAGEFLAGS) - 1;

for (i = 0; i < ARRAY_SIZE(pageflag_names) && flags; i++) {
for (i = 0; i < count && flags; i++) {

mask = pageflag_names[i].mask;
mask = names[i].mask;
if ((flags & mask) != mask)
continue;

flags &= ~mask;
printk("%s%s", delim, pageflag_names[i].name);
printk("%s%s", delim, names[i].name);
delim = "|";
}

Expand All @@ -6664,12 +6663,14 @@ void dump_page_badflags(struct page *page, const char *reason,
"page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
page, atomic_read(&page->_count), page_mapcount(page),
page->mapping, page->index);
dump_page_flags(page->flags);
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);
dump_flags(page->flags, pageflag_names, ARRAY_SIZE(pageflag_names));
if (reason)
pr_alert("page dumped because: %s\n", reason);
if (page->flags & badflags) {
pr_alert("bad because of flags:\n");
dump_page_flags(page->flags & badflags);
dump_flags(page->flags & badflags,
pageflag_names, ARRAY_SIZE(pageflag_names));
}
mem_cgroup_print_bad_page(page);
}
Expand All @@ -6679,3 +6680,66 @@ void dump_page(struct page *page, const char *reason)
dump_page_badflags(page, reason, 0);
}
EXPORT_SYMBOL(dump_page);

#ifdef CONFIG_DEBUG_VM

static const struct trace_print_flags vmaflags_names[] = {
{VM_READ, "read" },
{VM_WRITE, "write" },
{VM_EXEC, "exec" },
{VM_SHARED, "shared" },
{VM_MAYREAD, "mayread" },
{VM_MAYWRITE, "maywrite" },
{VM_MAYEXEC, "mayexec" },
{VM_MAYSHARE, "mayshare" },
{VM_GROWSDOWN, "growsdown" },
{VM_PFNMAP, "pfnmap" },
{VM_DENYWRITE, "denywrite" },
{VM_LOCKED, "locked" },
{VM_IO, "io" },
{VM_SEQ_READ, "seqread" },
{VM_RAND_READ, "randread" },
{VM_DONTCOPY, "dontcopy" },
{VM_DONTEXPAND, "dontexpand" },
{VM_ACCOUNT, "account" },
{VM_NORESERVE, "noreserve" },
{VM_HUGETLB, "hugetlb" },
{VM_NONLINEAR, "nonlinear" },
#if defined(CONFIG_X86)
{VM_PAT, "pat" },
#elif defined(CONFIG_PPC)
{VM_SAO, "sao" },
#elif defined(CONFIG_PARISC) || defined(CONFIG_METAG) || defined(CONFIG_IA64)
{VM_GROWSUP, "growsup" },
#elif !defined(CONFIG_MMU)
{VM_MAPPED_COPY, "mappedcopy" },
#else
{VM_ARCH_1, "arch_1" },
#endif
{VM_DONTDUMP, "dontdump" },
#ifdef CONFIG_MEM_SOFT_DIRTY
{VM_SOFTDIRTY, "softdirty" },
#endif
{VM_MIXEDMAP, "mixedmap" },
{VM_HUGEPAGE, "hugepage" },
{VM_NOHUGEPAGE, "nohugepage" },
{VM_MERGEABLE, "mergeable" },
};

void dump_vma(const struct vm_area_struct *vma)
{
printk(KERN_ALERT
"vma %p start %p end %p\n"
"next %p prev %p mm %p\n"
"prot %lx anon_vma %p vm_ops %p\n"
"pgoff %lx file %p private_data %p\n",
vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
vma->vm_prev, vma->vm_mm,
(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, vmaflags_names, ARRAY_SIZE(vmaflags_names));
}
EXPORT_SYMBOL(dump_vma);

#endif /* CONFIG_DEBUG_VM */

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