On Fri 18-12-15 10:03:26, Vlastimil Babka wrote:
> Since bad_page() is the only user of the badflags parameter of
> dump_page_badflags(), we can move the code to bad_page() and simplify a bit.
>
> The dump_page_badflags() function is renamed to __dump_page() and can still be
> called separately from dump_page() for temporary debug prints where page_owner
> info is not desired.
>
> The only user-visible change is that page->mem_cgroup is printed before the bad
> flags.
>
> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> include/linux/mmdebug.h | 3 +--
> mm/debug.c | 10 +++-------
> mm/page_alloc.c | 10 +++++++---
> 3 files changed, 11 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
> index 2c8286cf162e..9b0dc2161f7a 100644
> --- a/include/linux/mmdebug.h
> +++ b/include/linux/mmdebug.h
> @@ -14,8 +14,7 @@ extern const struct trace_print_flags vmaflag_names[];
> extern const struct trace_print_flags gfpflag_names[];
>
> extern void dump_page(struct page *page, const char *reason);
> -extern void dump_page_badflags(struct page *page, const char *reason,
> - unsigned long badflags);
> +extern void __dump_page(struct page *page, const char *reason);
> void dump_vma(const struct vm_area_struct *vma);
> void dump_mm(const struct mm_struct *mm);
>
> diff --git a/mm/debug.c b/mm/debug.c
> index 7260644d8cc1..4c03b6d07c82 100644
> --- a/mm/debug.c
> +++ b/mm/debug.c
> @@ -40,8 +40,7 @@ const struct trace_print_flags vmaflag_names[] = {
> {0, NULL}
> };
>
> -void dump_page_badflags(struct page *page, const char *reason,
> - unsigned long badflags)
> +void __dump_page(struct page *page, const char *reason)
> {
> pr_emerg("page:%p count:%d mapcount:%d mapping:%p index:%#lx",
> page, atomic_read(&page->_count), page_mapcount(page),
> @@ -50,15 +49,12 @@ void dump_page_badflags(struct page *page, const char *reason,
> pr_cont(" compound_mapcount: %d", compound_mapcount(page));
> pr_cont("\n");
> BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
> +
> pr_emerg("flags: %#lx(%pgp)\n", page->flags, &page->flags);
>
> if (reason)
> pr_alert("page dumped because: %s\n", reason);
>
> - badflags &= page->flags;
> - if (badflags)
> - pr_alert("bad because of flags: %#lx(%pgp)\n", badflags,
> - &badflags);
> #ifdef CONFIG_MEMCG
> if (page->mem_cgroup)
> pr_alert("page->mem_cgroup:%p\n", page->mem_cgroup);
> @@ -67,7 +63,7 @@ void dump_page_badflags(struct page *page, const char *reason,
>
> void dump_page(struct page *page, const char *reason)
> {
> - dump_page_badflags(page, reason, 0);
> + __dump_page(page, reason);
> dump_page_owner(page);
> }
> EXPORT_SYMBOL(dump_page);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 7718ee40726a..bac8842d4fcf 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -428,7 +428,7 @@ static void bad_page(struct page *page, const char *reason,
> goto out;
> }
> if (nr_unshown) {
> - printk(KERN_ALERT
> + pr_alert(
> "BUG: Bad page state: %lu messages suppressed\n",
> nr_unshown);
> nr_unshown = 0;
> @@ -438,9 +438,13 @@ static void bad_page(struct page *page, const char *reason,
> if (nr_shown++ == 0)
> resume = jiffies + 60 * HZ;
>
> - printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
> + pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
> current->comm, page_to_pfn(page));
> - dump_page_badflags(page, reason, bad_flags);
> + __dump_page(page, reason);
> + bad_flags &= page->flags;
> + if (bad_flags)
> + pr_alert("bad because of flags: %#lx(%pgp)\n",
> + bad_flags, &bad_flags);
> dump_page_owner(page);
>
> print_modules();
> --
> 2.6.3
--
Michal Hocko
SUSE Labs
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