[PATCH 1/3] Introduce dump_vma

Sasha Levin
2014-08-29T14:55:14Z

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)

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
include/linux/mmdebug.h | 2 ++
mm/page_alloc.c | 77 +++++++++++++++++++++++++++++++++++++++++------
2 files changed, 70 insertions(+), 9 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 2f348d0..dfb9333 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -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)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f86023b..add97b8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6628,27 +6628,26 @@ 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 = "|";
}

@@ -6666,12 +6665,14 @@ 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);
}
@@ -6681,3 +6682,61 @@ void dump_page(struct page *page, const char *reason)
dump_page_badflags(page, reason, 0);
}
EXPORT_SYMBOL(dump_page);
+
+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, vma->vm_page_prot.pgprot,
+ 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);
--
1.7.10.4