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-rw-r--r--crypto/async_tx/async_pq.c2
-rw-r--r--include/linux/page_ref.h98
-rw-r--r--include/trace/events/page_ref.h134
-rw-r--r--mm/Kconfig.debug13
-rw-r--r--mm/Makefile1
-rw-r--r--mm/debug_page_ref.c54
6 files changed, 296 insertions, 6 deletions
diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index c0748bbd4c08..08b3ac68952b 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -444,7 +444,7 @@ static int __init async_pq_init(void)
static void __exit async_pq_exit(void)
{
- put_page(pq_scribble_page);
+ __free_page(pq_scribble_page);
}
module_init(async_pq_init);
diff --git a/include/linux/page_ref.h b/include/linux/page_ref.h
index 30f5817f6b8e..e596d5d9540e 100644
--- a/include/linux/page_ref.h
+++ b/include/linux/page_ref.h
@@ -4,6 +4,62 @@
#include <linux/atomic.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
+#include <linux/tracepoint-defs.h>
+
+extern struct tracepoint __tracepoint_page_ref_set;
+extern struct tracepoint __tracepoint_page_ref_mod;
+extern struct tracepoint __tracepoint_page_ref_mod_and_test;
+extern struct tracepoint __tracepoint_page_ref_mod_and_return;
+extern struct tracepoint __tracepoint_page_ref_mod_unless;
+extern struct tracepoint __tracepoint_page_ref_freeze;
+extern struct tracepoint __tracepoint_page_ref_unfreeze;
+
+#ifdef CONFIG_DEBUG_PAGE_REF
+
+/*
+ * Ideally we would want to use the trace_<tracepoint>_enabled() helper
+ * functions. But due to include header file issues, that is not
+ * feasible. Instead we have to open code the static key functions.
+ *
+ * See trace_##name##_enabled(void) in include/linux/tracepoint.h
+ */
+#define page_ref_tracepoint_active(t) static_key_false(&(t).key)
+
+extern void __page_ref_set(struct page *page, int v);
+extern void __page_ref_mod(struct page *page, int v);
+extern void __page_ref_mod_and_test(struct page *page, int v, int ret);
+extern void __page_ref_mod_and_return(struct page *page, int v, int ret);
+extern void __page_ref_mod_unless(struct page *page, int v, int u);
+extern void __page_ref_freeze(struct page *page, int v, int ret);
+extern void __page_ref_unfreeze(struct page *page, int v);
+
+#else
+
+#define page_ref_tracepoint_active(t) false
+
+static inline void __page_ref_set(struct page *page, int v)
+{
+}
+static inline void __page_ref_mod(struct page *page, int v)
+{
+}
+static inline void __page_ref_mod_and_test(struct page *page, int v, int ret)
+{
+}
+static inline void __page_ref_mod_and_return(struct page *page, int v, int ret)
+{
+}
+static inline void __page_ref_mod_unless(struct page *page, int v, int u)
+{
+}
+static inline void __page_ref_freeze(struct page *page, int v, int ret)
+{
+}
+static inline void __page_ref_unfreeze(struct page *page, int v)
+{
+}
+
+#endif
static inline int page_ref_count(struct page *page)
{
@@ -18,6 +74,8 @@ static inline int page_count(struct page *page)
static inline void set_page_count(struct page *page, int v)
{
atomic_set(&page->_count, v);
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_set))
+ __page_ref_set(page, v);
}
/*
@@ -32,46 +90,74 @@ static inline void init_page_count(struct page *page)
static inline void page_ref_add(struct page *page, int nr)
{
atomic_add(nr, &page->_count);
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod))
+ __page_ref_mod(page, nr);
}
static inline void page_ref_sub(struct page *page, int nr)
{
atomic_sub(nr, &page->_count);
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod))
+ __page_ref_mod(page, -nr);
}
static inline void page_ref_inc(struct page *page)
{
atomic_inc(&page->_count);
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod))
+ __page_ref_mod(page, 1);
}
static inline void page_ref_dec(struct page *page)
{
atomic_dec(&page->_count);
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod))
+ __page_ref_mod(page, -1);
}
static inline int page_ref_sub_and_test(struct page *page, int nr)
{
- return atomic_sub_and_test(nr, &page->_count);
+ int ret = atomic_sub_and_test(nr, &page->_count);
+
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod_and_test))
+ __page_ref_mod_and_test(page, -nr, ret);
+ return ret;
}
static inline int page_ref_dec_and_test(struct page *page)
{
- return atomic_dec_and_test(&page->_count);
+ int ret = atomic_dec_and_test(&page->_count);
+
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod_and_test))
+ __page_ref_mod_and_test(page, -1, ret);
+ return ret;
}
static inline int page_ref_dec_return(struct page *page)
{
- return atomic_dec_return(&page->_count);
+ int ret = atomic_dec_return(&page->_count);
+
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod_and_return))
+ __page_ref_mod_and_return(page, -1, ret);
+ return ret;
}
static inline int page_ref_add_unless(struct page *page, int nr, int u)
{
- return atomic_add_unless(&page->_count, nr, u);
+ int ret = atomic_add_unless(&page->_count, nr, u);
+
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_mod_unless))
+ __page_ref_mod_unless(page, nr, ret);
+ return ret;
}
static inline int page_ref_freeze(struct page *page, int count)
{
- return likely(atomic_cmpxchg(&page->_count, count, 0) == count);
+ int ret = likely(atomic_cmpxchg(&page->_count, count, 0) == count);
+
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_freeze))
+ __page_ref_freeze(page, count, ret);
+ return ret;
}
static inline void page_ref_unfreeze(struct page *page, int count)
@@ -80,6 +166,8 @@ static inline void page_ref_unfreeze(struct page *page, int count)
VM_BUG_ON(count == 0);
atomic_set(&page->_count, count);
+ if (page_ref_tracepoint_active(__tracepoint_page_ref_unfreeze))
+ __page_ref_unfreeze(page, count);
}
#endif
diff --git a/include/trace/events/page_ref.h b/include/trace/events/page_ref.h
new file mode 100644
index 000000000000..81001f8b0db4
--- /dev/null
+++ b/include/trace/events/page_ref.h
@@ -0,0 +1,134 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM page_ref
+
+#if !defined(_TRACE_PAGE_REF_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PAGE_REF_H
+
+#include <linux/types.h>
+#include <linux/page_ref.h>
+#include <linux/tracepoint.h>
+#include <trace/events/mmflags.h>
+
+DECLARE_EVENT_CLASS(page_ref_mod_template,
+
+ TP_PROTO(struct page *page, int v),
+
+ TP_ARGS(page, v),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, pfn)
+ __field(unsigned long, flags)
+ __field(int, count)
+ __field(int, mapcount)
+ __field(void *, mapping)
+ __field(int, mt)
+ __field(int, val)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = page_to_pfn(page);
+ __entry->flags = page->flags;
+ __entry->count = page_ref_count(page);
+ __entry->mapcount = page_mapcount(page);
+ __entry->mapping = page->mapping;
+ __entry->mt = get_pageblock_migratetype(page);
+ __entry->val = v;
+ ),
+
+ TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d",
+ __entry->pfn,
+ show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)),
+ __entry->count,
+ __entry->mapcount, __entry->mapping, __entry->mt,
+ __entry->val)
+);
+
+DEFINE_EVENT(page_ref_mod_template, page_ref_set,
+
+ TP_PROTO(struct page *page, int v),
+
+ TP_ARGS(page, v)
+);
+
+DEFINE_EVENT(page_ref_mod_template, page_ref_mod,
+
+ TP_PROTO(struct page *page, int v),
+
+ TP_ARGS(page, v)
+);
+
+DECLARE_EVENT_CLASS(page_ref_mod_and_test_template,
+
+ TP_PROTO(struct page *page, int v, int ret),
+
+ TP_ARGS(page, v, ret),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, pfn)
+ __field(unsigned long, flags)
+ __field(int, count)
+ __field(int, mapcount)
+ __field(void *, mapping)
+ __field(int, mt)
+ __field(int, val)
+ __field(int, ret)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = page_to_pfn(page);
+ __entry->flags = page->flags;
+ __entry->count = page_ref_count(page);
+ __entry->mapcount = page_mapcount(page);
+ __entry->mapping = page->mapping;
+ __entry->mt = get_pageblock_migratetype(page);
+ __entry->val = v;
+ __entry->ret = ret;
+ ),
+
+ TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d ret=%d",
+ __entry->pfn,
+ show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)),
+ __entry->count,
+ __entry->mapcount, __entry->mapping, __entry->mt,
+ __entry->val, __entry->ret)
+);
+
+DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_mod_and_test,
+
+ TP_PROTO(struct page *page, int v, int ret),
+
+ TP_ARGS(page, v, ret)
+);
+
+DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_mod_and_return,
+
+ TP_PROTO(struct page *page, int v, int ret),
+
+ TP_ARGS(page, v, ret)
+);
+
+DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_mod_unless,
+
+ TP_PROTO(struct page *page, int v, int ret),
+
+ TP_ARGS(page, v, ret)
+);
+
+DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_freeze,
+
+ TP_PROTO(struct page *page, int v, int ret),
+
+ TP_ARGS(page, v, ret)
+);
+
+DEFINE_EVENT(page_ref_mod_template, page_ref_unfreeze,
+
+ TP_PROTO(struct page *page, int v),
+
+ TP_ARGS(page, v)
+);
+
+#endif /* _TRACE_PAGE_COUNT_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 5c50b238b770..22f4cd96acb0 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -79,3 +79,16 @@ config PAGE_POISONING_ZERO
Enabling page poisoning with this option will disable hibernation
If unsure, say N
+ bool
+
+config DEBUG_PAGE_REF
+ bool "Enable tracepoint to track down page reference manipulation"
+ depends on DEBUG_KERNEL
+ depends on TRACEPOINTS
+ ---help---
+ This is a feature to add tracepoint for tracking down page reference
+ manipulation. This tracking is useful to diagnose functional failure
+ due to migration failures caused by page reference mismatches. Be
+ careful when enabling this feature because it adds about 30 KB to the
+ kernel code. However the runtime performance overhead is virtually
+ nil until the tracepoints are actually enabled.
diff --git a/mm/Makefile b/mm/Makefile
index cfdd481d27a5..6da300a1414b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -81,3 +81,4 @@ obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o
obj-$(CONFIG_USERFAULTFD) += userfaultfd.o
obj-$(CONFIG_IDLE_PAGE_TRACKING) += page_idle.o
obj-$(CONFIG_FRAME_VECTOR) += frame_vector.o
+obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o
diff --git a/mm/debug_page_ref.c b/mm/debug_page_ref.c
new file mode 100644
index 000000000000..1aef3d562e52
--- /dev/null
+++ b/mm/debug_page_ref.c
@@ -0,0 +1,54 @@
+#include <linux/mm_types.h>
+#include <linux/tracepoint.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/page_ref.h>
+
+void __page_ref_set(struct page *page, int v)
+{
+ trace_page_ref_set(page, v);
+}
+EXPORT_SYMBOL(__page_ref_set);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_set);
+
+void __page_ref_mod(struct page *page, int v)
+{
+ trace_page_ref_mod(page, v);
+}
+EXPORT_SYMBOL(__page_ref_mod);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_mod);
+
+void __page_ref_mod_and_test(struct page *page, int v, int ret)
+{
+ trace_page_ref_mod_and_test(page, v, ret);
+}
+EXPORT_SYMBOL(__page_ref_mod_and_test);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_test);
+
+void __page_ref_mod_and_return(struct page *page, int v, int ret)
+{
+ trace_page_ref_mod_and_return(page, v, ret);
+}
+EXPORT_SYMBOL(__page_ref_mod_and_return);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_return);
+
+void __page_ref_mod_unless(struct page *page, int v, int u)
+{
+ trace_page_ref_mod_unless(page, v, u);
+}
+EXPORT_SYMBOL(__page_ref_mod_unless);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_unless);
+
+void __page_ref_freeze(struct page *page, int v, int ret)
+{
+ trace_page_ref_freeze(page, v, ret);
+}
+EXPORT_SYMBOL(__page_ref_freeze);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_freeze);
+
+void __page_ref_unfreeze(struct page *page, int v)
+{
+ trace_page_ref_unfreeze(page, v);
+}
+EXPORT_SYMBOL(__page_ref_unfreeze);
+EXPORT_TRACEPOINT_SYMBOL(page_ref_unfreeze);