mm/page_isolation.c: add new tracepoint, test_pages_isolated

cma allocation should be guranteeded to succeed.  But sometimes it can
fail in the current implementation.  To track down the problem, we need
to know which page is problematic and this new tracepoint will report
it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/trace/events/page_isolation.h b/include/trace/events/page_isolation.h
new file mode 100644 (file)
index 0000000..6fb6440
--- /dev/null
+++ b/include/trace/events/page_isolation.h
@@ -0,0 +1,38 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM page_isolation
+
+#if !defined(_TRACE_PAGE_ISOLATION_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PAGE_ISOLATION_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(test_pages_isolated,
+
+       TP_PROTO(
+               unsigned long start_pfn,
+               unsigned long end_pfn,
+               unsigned long fin_pfn),
+
+       TP_ARGS(start_pfn, end_pfn, fin_pfn),
+
+       TP_STRUCT__entry(
+               __field(unsigned long, start_pfn)
+               __field(unsigned long, end_pfn)
+               __field(unsigned long, fin_pfn)
+       ),
+
+       TP_fast_assign(
+               __entry->start_pfn = start_pfn;
+               __entry->end_pfn = end_pfn;
+               __entry->fin_pfn = fin_pfn;
+       ),
+
+       TP_printk("start_pfn=0x%lx end_pfn=0x%lx fin_pfn=0x%lx ret=%s",
+               __entry->start_pfn, __entry->end_pfn, __entry->fin_pfn,
+               __entry->end_pfn == __entry->fin_pfn ? "success" : "fail")
+);
+
+#endif /* _TRACE_PAGE_ISOLATION_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 029a171d35dcbbe16ea3f704f589c339f9614fd5..f484b9300fe325c9031866d07d793c99e0a6a178 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -9,6 +9,9 @@
 #include <linux/hugetlb.h>
 #include "internal.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/page_isolation.h>
+
 static int set_migratetype_isolate(struct page *page,
                                bool skip_hwpoisoned_pages)
 {
@@ -268,6 +271,8 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
                                                skip_hwpoisoned_pages);
        spin_unlock_irqrestore(&zone->lock, flags);
 
+       trace_test_pages_isolated(start_pfn, end_pfn, pfn);
+
        return pfn < end_pfn ? -EBUSY : 0;
 }