Count ABD memory usage

Adds two kstat entries to the `arcstats` file for ABD memory usage - headers and data. Data will always be a size multiple of the system page size.
DeHackEd · Oct 3, 2014 · 3ff7ae2 · 3ff7ae2
1 parent 7719a94
commit 3ff7ae2
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Showing 3 changed files with 34 additions and 8 deletions.
diff --git a/include/sys/arc.h b/include/sys/arc.h
@@ -90,6 +90,8 @@ typedef enum arc_space_type {
 	ARC_SPACE_META,
 	ARC_SPACE_HDRS,
 	ARC_SPACE_L2HDRS,
+	ARC_SPACE_ABD_DATA,
+	ARC_SPACE_ABD_HDRS,
 	ARC_SPACE_OTHER,
 	ARC_SPACE_NUMTYPES
 } arc_space_type_t;

diff --git a/module/zfs/abd.c b/module/zfs/abd.c
@@ -24,6 +24,7 @@
  */
 
 #include <sys/abd.h>
+#include <sys/arc.h>
 #ifdef _KERNEL
 #include <linux/kernel.h>
 #include <linux/sched.h>
@@ -819,9 +820,9 @@ abd_alloc(size_t size)
 	arc_buf_data_t *abd;
 	struct page *page;
 	int i, n = DIV_ROUND_UP(size, PAGE_SIZE);
-
-	abd = kmem_alloc(sizeof (arc_buf_data_t) +
-	    n * sizeof (struct scatterlist), KM_PUSHPAGE);
+	const int headersize = sizeof(arc_buf_data_t) + 
+	    n * sizeof(struct scatterlist);
+	abd = kmem_alloc(headersize, KM_PUSHPAGE);
 
 	ASSERT(abd);
 	ASSERT_ABD_LINEAR(abd);
@@ -842,7 +843,8 @@ abd_alloc(size_t size)
 		}
 		sg_set_page(&abd->abd_sgl[i], page, PAGE_SIZE, 0);
 	}
-
+	arc_space_consume(headersize, ARC_SPACE_ABD_HDRS);
+	arc_space_consume(PAGE_SIZE * n, ARC_SPACE_ABD_DATA);
 	return (abd_t *)(((unsigned long)abd)|0x1);
 }
 
@@ -856,13 +858,17 @@ abd_free(abd_t *__abd, size_t size)
 	ASSERT(abd->abd_sgl == &abd->__abd_sgl[0]);
 	ASSERT(abd->abd_size == size);
 	n =  DIV_ROUND_UP(abd->abd_size, PAGE_SIZE);
+	const int headersize = sizeof(arc_buf_data_t) + 
+	    n * sizeof(struct scatterlist);
 
 	abd->abd_magic = 0;
 	for (i = 0; i < n; i++) {
 		page = sg_page(&abd->abd_sgl[i]);
 		if (page)
 			__free_page(page);
 	}
-	kmem_free(abd, sizeof (arc_buf_data_t) +
-	    n * sizeof (struct scatterlist));
+	kmem_free(abd, headersize);
+	arc_space_return(headersize, ARC_SPACE_ABD_HDRS);
+	arc_space_return(PAGE_SIZE * n, ARC_SPACE_ABD_DATA);
 }
+
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
@@ -364,6 +364,8 @@ typedef struct arc_stats {
 	kstat_named_t arcstat_meta_used;
 	kstat_named_t arcstat_meta_limit;
 	kstat_named_t arcstat_meta_max;
+	kstat_named_t arcstat_abd_data_size;
+	kstat_named_t arcstat_abd_hdr_size;
 } arc_stats_t;
 
 static arc_stats_t arc_stats = {
@@ -452,6 +454,8 @@ static arc_stats_t arc_stats = {
 	{ "arc_meta_used",		KSTAT_DATA_UINT64 },
 	{ "arc_meta_limit",		KSTAT_DATA_UINT64 },
 	{ "arc_meta_max",		KSTAT_DATA_UINT64 },
+	{ "abd_data_size",		KSTAT_DATA_UINT64 },
+	{ "abd_hdr_size",		KSTAT_DATA_UINT64 },
 };
 
 #define	ARCSTAT(stat)	(arc_stats.stat.value.ui64)
@@ -1401,9 +1405,16 @@ arc_space_consume(uint64_t space, arc_space_type_t type)
 	case ARC_SPACE_L2HDRS:
 		ARCSTAT_INCR(arcstat_l2_hdr_size, space);
 		break;
+        case ARC_SPACE_ABD_DATA:
+                ARCSTAT_INCR(arcstat_abd_data_size, space);
+                /* Return because otherwise we double-count data space */
+                return;
+        case ARC_SPACE_ABD_HDRS:
+                ARCSTAT_INCR(arcstat_abd_hdr_size, space);
+                break;
 	}
 
-	if (type != ARC_SPACE_DATA)
+	if (type != ARC_SPACE_DATA && type != ARC_SPACE_ABD_DATA)
 		ARCSTAT_INCR(arcstat_meta_used, space);
 
 	atomic_add_64(&arc_size, space);
@@ -1432,9 +1443,16 @@ arc_space_return(uint64_t space, arc_space_type_t type)
 	case ARC_SPACE_L2HDRS:
 		ARCSTAT_INCR(arcstat_l2_hdr_size, -space);
 		break;
+        case ARC_SPACE_ABD_DATA:
+                ARCSTAT_INCR(arcstat_abd_data_size, -space);
+                /* Return because otherwise we double-count data space */
+                return;
+        case ARC_SPACE_ABD_HDRS:
+                ARCSTAT_INCR(arcstat_abd_hdr_size, -space);
+                break;
 	}
 
-	if (type != ARC_SPACE_DATA) {
+	if (type != ARC_SPACE_DATA && type != ARC_SPACE_ABD_DATA) {
 		ASSERT(arc_meta_used >= space);
 		if (arc_meta_max < arc_meta_used)
 			arc_meta_max = arc_meta_used;