Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1268552 > unrolled thread

[PATCH 1/3] mm/page_isolation: return last tested pfn rather than failure indicator

Back to article view | Back to linux.kernel

Contents

  [PATCH 1/3] mm/page_isolation: return last tested pfn rather than failure indicator Joonsoo Kim <js1304@gmail.com> - 2015-11-13 03:30 +0100
    [PATCH 2/3] mm/page_isolation: add new tracepoint, test_pages_isolated Joonsoo Kim <js1304@gmail.com> - 2015-11-13 03:30 +0100
      Re: [PATCH 2/3] mm/page_isolation: add new tracepoint,  test_pages_isolated David Rientjes <rientjes@google.com> - 2015-11-14 00:00 +0100
    [PATCH 3/3] mm/cma: always check which page cause allocation failure Joonsoo Kim <js1304@gmail.com> - 2015-11-13 03:30 +0100

#1268552 — [PATCH 1/3] mm/page_isolation: return last tested pfn rather than failure indicator

This is preparation step to report test failed pfn in new tracepoint
to analyze cma allocation failure problem. There is no functional change
in this patch.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/page_isolation.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 4568fd5..029a171 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -212,7 +212,7 @@ int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
  *
  * Returns 1 if all pages in the range are isolated.
  */
-static int
+static unsigned long
 __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
 				  bool skip_hwpoisoned_pages)
 {
@@ -237,9 +237,8 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
 		else
 			break;
 	}
-	if (pfn < end_pfn)
-		return 0;
-	return 1;
+
+	return pfn;
 }
 
 int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
@@ -248,7 +247,6 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
 	unsigned long pfn, flags;
 	struct page *page;
 	struct zone *zone;
-	int ret;
 
 	/*
 	 * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages
@@ -266,10 +264,11 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
 	/* Check all pages are free or marked as ISOLATED */
 	zone = page_zone(page);
 	spin_lock_irqsave(&zone->lock, flags);
-	ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
+	pfn = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
 						skip_hwpoisoned_pages);
 	spin_unlock_irqrestore(&zone->lock, flags);
-	return ret ? 0 : -EBUSY;
+
+	return pfn < end_pfn ? -EBUSY : 0;
 }
 
 struct page *alloc_migrate_target(struct page *page, unsigned long private,
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1268553 — [PATCH 2/3] mm/page_isolation: add new tracepoint, test_pages_isolated

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

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 include/trace/events/page_isolation.h | 38 +++++++++++++++++++++++++++++++++++
 mm/page_isolation.c                   |  5 +++++
 2 files changed, 43 insertions(+)
 create mode 100644 include/trace/events/page_isolation.h

diff --git a/include/trace/events/page_isolation.h b/include/trace/events/page_isolation.h
new file mode 100644
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 029a171..f484b93 100644
--- 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;
 }
 
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1269354 — Re: [PATCH 2/3] mm/page_isolation: add new tracepoint, test_pages_isolated

On Fri, 13 Nov 2015, Joonsoo Kim wrote:

> cma allocation should be guranteeded to succeed, but, sometimes,
> it could be failed in current implementation. To track down
> the problem, we need to know which page is problematic and
> this new tracepoint will report it.
> 
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Acked-by: David Rientjes <rientjes@google.com>

Thanks for generalizing this!
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1268555 — [PATCH 3/3] mm/cma: always check which page cause allocation failure

Now, we have tracepoint in test_pages_isolated() to notify
pfn which cannot be isolated. But, in alloc_contig_range(),
some error path doesn't call test_pages_isolated() so it's still
hard to know exact pfn that causes allocation failure.

This patch change this situation by calling test_pages_isolated()
in almost error path. In allocation failure case, some overhead
is added by this change, but, allocation failure is really rare
event so it would not matter.

In fatal signal pending case, we don't call test_pages_isolated()
because this failure is intentional one.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/page_alloc.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d89960d..e78d78f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6756,8 +6756,12 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 	if (ret)
 		return ret;
 
+	/*
+	 * In case of -EBUSY, we'd like to know which page causes problem.
+	 * So, just fall through. We will check it in test_pages_isolated().
+	 */
 	ret = __alloc_contig_migrate_range(&cc, start, end);
-	if (ret)
+	if (ret && ret != -EBUSY)
 		goto done;
 
 	/*
@@ -6784,8 +6788,8 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 	outer_start = start;
 	while (!PageBuddy(pfn_to_page(outer_start))) {
 		if (++order >= MAX_ORDER) {
-			ret = -EBUSY;
-			goto done;
+			outer_start = start;
+			break;
 		}
 		outer_start &= ~0UL << order;
 	}
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web