The patch titled
Subject: mm: print more information about mapping in __dump_page
has been removed from the -mm tree. Its filename was
mm-print-more-information-about-mapping-in-__dump_page.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm: print more information about mapping in __dump_page
I have been promissing to improve memory offlining failures debugging for
quite some time. As things stand now we get only very limited information
in the kernel log when the offlining fails. It is usually only
[ 1984.506184] rac1 kernel: memory offlining [mem 0x82600000000-0x8267fffffff] failed
with no further details. We do not know what exactly fails and for what
reason. Whenever I was forced to debug such a failure I've always had to
do a debugging patch to tell me more. We can enable some tracepoints but
it would be much better to get a better picture without using them.
This patch series does 2 things. The first one is to make dump_page more
usable by printing more information about the mapping patch 1. Then it
reduces the log level from emerg to warning so that this function is
usable from less critical context patch 2. Then I have added more
detailed information about the offlining failure patch 4 and finally add
dump_page to isolation and offlining migration paths. Patch 3 is a
trivial cleanup.
This patch (of 6):
__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.
[dan.carpenter@xxxxxxxxxx: fix a width vs precision bug in printk]
Link: http://lkml.kernel.org/r/20181123072135.gqvblm2vdujbvfjs@kili.mountain
[mhocko@xxxxxxxxxx: use %dp to print dentry]
Link: http://lkml.kernel.org/r/20181125080834.GB12455@xxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20181107101830.17405-2-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Cc: Oscar Salvador <OSalvador@xxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/debug.c~mm-print-more-information-about-mapping-in-__dump_page
+++ a/mm/debug.c
@@ -44,6 +44,7 @@ const struct trace_print_flags vmaflag_n
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, cons
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:\"%pd\" ", dentry);
+ }
+ }
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
mm-memcg-fix-reclaim-deadlock-with-writeback.patch
