| Message ID | 20181116083020.20260-2-mhocko@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm, memory_hotplug: improve memory offlining failures debugging | expand |
On 11/16/2018 02:00 PM, Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > __dump_page prints the mapping pointer but that is quite unhelpful > for many reports because the pointer itself only helps to distinguish > anon/ksm mappings from other ones (because of lowest bits > set). Sometimes it would be much more helpful to know what kind of > mapping that is actually and if we know this is a file mapping then also > try to resolve the dentry name. > > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > mm/debug.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/mm/debug.c b/mm/debug.c > index cdacba12e09a..a33177bfc856 100644 > --- a/mm/debug.c > +++ b/mm/debug.c > @@ -44,6 +44,7 @@ const struct trace_print_flags vmaflag_names[] = { > > void __dump_page(struct page *page, const char *reason) > { > + struct address_space *mapping = page_mapping(page); > bool page_poisoned = PagePoisoned(page); > int mapcount; > > @@ -70,6 +71,18 @@ void __dump_page(struct page *page, const char *reason) > if (PageCompound(page)) > pr_cont(" compound_mapcount: %d", compound_mapcount(page)); > pr_cont("\n"); > + if (PageAnon(page)) > + pr_emerg("anon "); > + else if (PageKsm(page)) > + pr_emerg("ksm "); > + else if (mapping) { > + pr_emerg("%ps ", mapping->a_ops); > + if (mapping->host->i_dentry.first) { > + struct dentry *dentry; > + dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias); > + pr_emerg("name:\"%*s\" ", dentry->d_name.len, dentry->d_name.name); > + } > + } > BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); > > pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags); > Differentiating between anon, ksm mapping and going till dentry information for file mappings is surely an improvement. Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
> On Nov 16, 2018, at 1:30 AM, Michal Hocko <mhocko@kernel.org> wrote: > > From: Michal Hocko <mhocko@suse.com> > > __dump_page prints the mapping pointer but that is quite unhelpful > for many reports because the pointer itself only helps to distinguish > anon/ksm mappings from other ones (because of lowest bits > set). Sometimes it would be much more helpful to know what kind of > mapping that is actually and if we know this is a file mapping then also > try to resolve the dentry name. I really, really like this - the more information available in the dump output, the easier it is to know where to start looking for the problem. Reviewed-by: William Kucharski <william.kucharski@oracle.com>
diff --git a/mm/debug.c b/mm/debug.c index cdacba12e09a..a33177bfc856 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -44,6 +44,7 @@ const struct trace_print_flags vmaflag_names[] = { void __dump_page(struct page *page, const char *reason) { + struct address_space *mapping = page_mapping(page); bool page_poisoned = PagePoisoned(page); int mapcount; @@ -70,6 +71,18 @@ void __dump_page(struct page *page, const char *reason) if (PageCompound(page)) pr_cont(" compound_mapcount: %d", compound_mapcount(page)); pr_cont("\n"); + if (PageAnon(page)) + pr_emerg("anon "); + else if (PageKsm(page)) + pr_emerg("ksm "); + else if (mapping) { + pr_emerg("%ps ", mapping->a_ops); + if (mapping->host->i_dentry.first) { + struct dentry *dentry; + dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias); + pr_emerg("name:\"%*s\" ", dentry->d_name.len, dentry->d_name.name); + } + } BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);