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Subject[PATCH v2 3/4] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext
Date
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
rather 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/pagemap.h | 36 +++++++++++++++----
lib/Kconfig.debug | 1 +
mm/filemap.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++
mm/page_alloc.c | 3 --
mm/page_ext.c | 4 +++
7 files changed, 138 insertions(+), 16 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 263b861..bc52a4a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -222,10 +222,6 @@ 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 108d2dd..32ae372 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -375,28 +375,41 @@ static __always_inline int PageSwapCache(struct page *page)

#ifdef CONFIG_LOCKDEP_PAGELOCK
#include <linux/lockdep.h>
+extern struct lockdep_map *get_page_map(struct page *p);

TESTPAGEFLAG(Locked, locked, PF_NO_TAIL)

static __always_inline void __SetPageLocked(struct page *page)
{
+ struct lockdep_map *m;
+
__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_);
+ m = get_page_map(page);
+ if (unlikely(!m))
+ return;
+
+ lock_acquire_exclusive(m, 0, 1, NULL, _RET_IP_);
}

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

page = compound_head(page);
+ m = get_page_map(page);
+ if (unlikely(!m))
+ 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(m);
+ lock_release(m, 0, _RET_IP_);
}
#else
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 35b4f67..6722ef7 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -17,6 +17,7 @@
#include <linux/hugetlb_inline.h>
#ifdef CONFIG_LOCKDEP_PAGELOCK
#include <linux/lockdep.h>
+#include <linux/page_ext.h>
#endif

/*
@@ -461,34 +462,57 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
}

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

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

static inline void lock_page_release(struct page *page)
{
+ struct lockdep_map *m;
+
page = compound_head(page);
+ m = get_page_map(page);
+ if (unlikely(!m))
+ 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(m);
+ lock_release(m, 0, _RET_IP_);
}
#else
static inline void lock_page_init(struct page *page) {}
static inline void lock_page_free(struct page *page) {}
static inline void lock_page_acquire(struct page *page, int try) {}
static inline void lock_page_release(struct page *page) {}
+
+static inline struct lockdep_map *get_page_map(struct page *page)
+{
+ return NULL;
+}
#endif

extern void __lock_page(struct page *page);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2e8c679..45fdb3a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1182,6 +1182,7 @@ config LOCKDEP_COMPLETIONS

config LOCKDEP_PAGELOCK
bool
+ select PAGE_EXTENSION
help
PG_locked lock is a kind of crosslock. Using crossrelease feature,
PG_locked lock can work with lockdep.
diff --git a/mm/filemap.c b/mm/filemap.c
index 870d442..34251fb 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
@@ -1226,6 +1229,90 @@ 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;
+ 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;
+
+ lock_page_init(page);
+
+ if (get_page_map(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 = {
+ .size = sizeof(struct lockdep_map_cross),
+ .need = need_lockdep_pagelock,
+ .init = init_lockdep_pagelock,
+};
+
+/*
+ * Even though we reserved a space sized of struct lockdep_map_cross,
+ * we only return it as struct lockdep_map, because a full instance of
+ * lockdep_map_cross is only for lockdep cross-release internal.
+ */
+struct lockdep_map *get_page_map(struct page *p)
+{
+ struct page_ext *e;
+
+ e = lookup_page_ext(p);
+ if (!e)
+ return NULL;
+
+ return (void *)e + lockdep_pagelock_ops.offset;
+}
+#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 8436b28..77e4d3c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5371,9 +5371,6 @@ 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 4f0367d..63ae336 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -8,6 +8,7 @@
#include <linux/kmemleak.h>
#include <linux/page_owner.h>
#include <linux/page_idle.h>
+#include <linux/pagemap.h>

/*
* struct page extension
@@ -66,6 +67,9 @@
#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
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