[PATCH v8 13/14] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext

Byungchul Park
2017-08-07T07:14:15Z

CONFIG_LOCKDEP_PAGELOCK needs to keep lockdep_map_cross per page. Since
it's a debug feature, it's preferred to keep it in struct page_ext than
struct page. Move it to struct page_ext.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
include/linux/mm_types.h | 4 ---
include/linux/page-flags.h | 19 +++++++++++--
include/linux/page_ext.h | 4 +++
include/linux/pagemap.h | 28 ++++++++++++++++---
lib/Kconfig.debug | 1 +
mm/filemap.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++
mm/page_alloc.c | 3 --
mm/page_ext.c | 4 +++
8 files changed, 118 insertions(+), 14 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index f1e3dba..ac3121c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -220,10 +220,6 @@ struct page {
#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
int _last_cpupid;
#endif
-
-#ifdef CONFIG_LOCKDEP_PAGELOCK
- struct lockdep_map_cross map;
-#endif
}
/*
* The struct page can be forced to be double word aligned so that atomic ops
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index b793342..879dd0d 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -374,28 +374,41 @@ static __always_inline int PageSwapCache(struct page *page)

#ifdef CONFIG_LOCKDEP_PAGELOCK
#include <linux/lockdep.h>
+#include <linux/page_ext.h>

TESTPAGEFLAG(Locked, locked, PF_NO_TAIL)

static __always_inline void __SetPageLocked(struct page *page)
{
+ struct page_ext *e;
+
__set_bit(PG_locked, &PF_NO_TAIL(page, 1)->flags);

page = compound_head(page);
- lock_acquire_exclusive((struct lockdep_map *)&page->map, 0, 1, NULL, _RET_IP_);
+ e = lookup_page_ext(page);
+ if (unlikely(!e))
+ return;
+
+ lock_acquire_exclusive((struct lockdep_map *)&e->map, 0, 1, NULL, _RET_IP_);
}

static __always_inline void __ClearPageLocked(struct page *page)
{
+ struct page_ext *e;
+
__clear_bit(PG_locked, &PF_NO_TAIL(page, 1)->flags);

page = compound_head(page);
+ e = lookup_page_ext(page);
+ if (unlikely(!e))
+ return;
+
/*
* lock_commit_crosslock() is necessary for crosslock
* when the lock is released, before lock_release().
*/
- lock_commit_crosslock((struct lockdep_map *)&page->map);
- lock_release((struct lockdep_map *)&page->map, 0, _RET_IP_);
+ lock_commit_crosslock((struct lockdep_map *)&e->map);
+ lock_release((struct lockdep_map *)&e->map, 0, _RET_IP_);
}
#else
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index 9298c39..d1c52c8c 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -44,6 +44,10 @@ enum page_ext_flags {
*/
struct page_ext {
unsigned long flags;
+
+#ifdef CONFIG_LOCKDEP_PAGELOCK
+ struct lockdep_map_cross map;
+#endif
};

extern void pgdat_page_ext_init(struct pglist_data *pgdat);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 9f448c6..b75b8bc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -16,6 +16,7 @@
#include <linux/hugetlb_inline.h>
#ifdef CONFIG_LOCKDEP_PAGELOCK
#include <linux/lockdep.h>
+#include <linux/page_ext.h>
#endif

/*
@@ -454,28 +455,47 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
}

#ifdef CONFIG_LOCKDEP_PAGELOCK
+extern struct page_ext_operations lockdep_pagelock_ops;
+
#define lock_page_init(p) \
do { \
static struct lock_class_key __key; \
- lockdep_init_map_crosslock((struct lockdep_map *)&(p)->map, \
+ struct page_ext *e = lookup_page_ext(p); \
+ \
+ if (unlikely(!e)) \
+ break; \
+ \
+ lockdep_init_map_crosslock((struct lockdep_map *)&(e)->map, \
"(PG_locked)" #p, &__key, 0); \
} while (0)

static inline void lock_page_acquire(struct page *page, int try)
{
+ struct page_ext *e;
+
page = compound_head(page);
- lock_acquire_exclusive((struct lockdep_map *)&page->map, 0,
+ e = lookup_page_ext(page);
+ if (unlikely(!e))
+ return;
+
+ lock_acquire_exclusive((struct lockdep_map *)&e->map, 0,
try, NULL, _RET_IP_);
}

static inline void lock_page_release(struct page *page)
{
+ struct page_ext *e;
+
page = compound_head(page);
+ e = lookup_page_ext(page);
+ if (unlikely(!e))
+ return;
+
/*
* lock_commit_crosslock() is necessary for crosslocks.
*/
- lock_commit_crosslock((struct lockdep_map *)&page->map);
- lock_release((struct lockdep_map *)&page->map, 0, _RET_IP_);
+ lock_commit_crosslock((struct lockdep_map *)&e->map);
+ lock_release((struct lockdep_map *)&e->map, 0, _RET_IP_);
}
#else
static inline void lock_page_init(struct page *page) {}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 99b5f76..3a890fb 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1096,6 +1096,7 @@ config LOCKDEP_COMPLETE
config LOCKDEP_PAGELOCK
bool "Lock debugging: allow PG_locked lock to use deadlock detector"
select LOCKDEP_CROSSRELEASE
+ select PAGE_EXTENSION
default n
help
PG_locked lock is a kind of crosslock. Using crossrelease feature,
diff --git a/mm/filemap.c b/mm/filemap.c
index 0d83bf0..6372bd8 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -36,6 +36,9 @@
#include <linux/memcontrol.h>
#include <linux/cleancache.h>
#include <linux/rmap.h>
+#ifdef CONFIG_LOCKDEP_PAGELOCK
+#include <linux/page_ext.h>
+#endif
#include "internal.h"

#define CREATE_TRACE_POINTS
@@ -1210,6 +1213,72 @@ int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
}
}

+#ifdef CONFIG_LOCKDEP_PAGELOCK
+static bool need_lockdep_pagelock(void) { return true; }
+
+static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
+{
+ struct page *page;
+ struct page_ext *page_ext;
+ unsigned long pfn = zone->zone_start_pfn;
+ unsigned long end_pfn = pfn + zone->spanned_pages;
+ unsigned long count = 0;
+
+ for (; pfn < end_pfn; pfn++) {
+ if (!pfn_valid(pfn)) {
+ pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
+ continue;
+ }
+
+ if (!pfn_valid_within(pfn))
+ continue;
+
+ page = pfn_to_page(pfn);
+
+ if (page_zone(page) != zone)
+ continue;
+
+ page_ext = lookup_page_ext(page);
+ if (unlikely(!page_ext))
+ continue;
+
+ lock_page_init(page);
+ count++;
+ }
+
+ pr_info("Node %d, zone %8s: lockdep pagelock found early allocated %lu pages\n",
+ pgdat->node_id, zone->name, count);
+}
+
+static void init_zones_in_node(pg_data_t *pgdat)
+{
+ struct zone *zone;
+ struct zone *node_zones = pgdat->node_zones;
+ unsigned long flags;
+
+ for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+ if (!populated_zone(zone))
+ continue;
+
+ spin_lock_irqsave(&zone->lock, flags);
+ init_pages_in_zone(pgdat, zone);
+ spin_unlock_irqrestore(&zone->lock, flags);
+ }
+}
+
+static void init_lockdep_pagelock(void)
+{
+ pg_data_t *pgdat;
+ for_each_online_pgdat(pgdat)
+ init_zones_in_node(pgdat);
+}
+
+struct page_ext_operations lockdep_pagelock_ops = {
+ .need = need_lockdep_pagelock,
+ .init = init_lockdep_pagelock,
+};
+#endif
+
/**
* page_cache_next_hole - find the next hole (not-present entry)
* @mapping: mapping
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2cbf412..6d30e91 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5406,9 +5406,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
} else {
__init_single_pfn(pfn, zone, nid);
}
-#ifdef CONFIG_LOCKDEP_PAGELOCK
- lock_page_init(pfn_to_page(pfn));
-#endif
}
}

diff --git a/mm/page_ext.c b/mm/page_ext.c
index 88ccc044..2ac1fb1 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -7,6 +7,7 @@
#include <linux/kmemleak.h>
#include <linux/page_owner.h>
#include <linux/page_idle.h>
+#include <linux/pagemap.h>

/*
* struct page extension
@@ -65,6 +66,9 @@
#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
&page_idle_ops,
#endif
+#ifdef CONFIG_LOCKDEP_PAGELOCK
+ &lockdep_pagelock_ops,
+#endif
};

static unsigned long total_usage;
--
1.9.1