10:12 p.m.
From: Bing Niu <bing.niu(a)intel.com>
Add memory bandwidth allocation support to virresctrl class.
Introducing virResctrlAllocMemBW which is used for allocating memory
bandwidth. Following virResctrlAllocPerType, it also employs a
nested sparse array to indicate whether allocation is available for
particular last level cache.
Signed-off-by: Bing Niu <bing.niu(a)intel.com>
---
src/util/virresctrl.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 59 insertions(+), 4 deletions(-)
diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c
index f454868..8a25798 100644
--- a/src/util/virresctrl.c
+++ b/src/util/virresctrl.c
@@ -36,9 +36,9 @@ VIR_LOG_INIT("util.virresctrl")
/* Resctrl is short for Resource Control. It might be implemented for various
- * resources, but at the time of this writing this is only supported for cache
- * allocation technology (aka CAT). Hence the reson for leaving 'Cache' out of
- * all the structure and function names for now (can be added later if needed.
+ * resources. Currently this supports cache allocation technology (aka CAT) and
+ * memory bandwidth allocation (aka MBA). More resources technologies may be
+ * added in the future.
*/
@@ -89,6 +89,9 @@ typedef virResctrlAllocPerType *virResctrlAllocPerTypePtr;
typedef struct _virResctrlAllocPerLevel virResctrlAllocPerLevel;
typedef virResctrlAllocPerLevel *virResctrlAllocPerLevelPtr;
+typedef struct _virResctrlAllocMemBW virResctrlAllocMemBW;
+typedef virResctrlAllocMemBW *virResctrlAllocMemBWPtr;
+
/* Class definitions and initializations */
static virClassPtr virResctrlInfoClass;
@@ -180,7 +183,10 @@ virResctrlInfoDispose(void *obj)
* consequently a directory under /sys/fs/resctrl). Since it can have multiple
* parts of multiple caches allocated it is represented as bunch of nested
* sparse arrays (by sparse I mean array of pointers so that each might be NULL
- * in case there is no allocation for that particular one (level, cache, ...)).
+ * in case there is no allocation for that particular cache allocation (level,
+ * cache, ...) or memory allocation for particular node).
+ *
+ * =====Cache allocation technology (CAT)=====
*
* Since one allocation can be made for caches on different levels, the first
* nested sparse array is of types virResctrlAllocPerLevel. For example if you
@@ -205,6 +211,17 @@ virResctrlInfoDispose(void *obj)
* all of them. While doing that we store the bitmask in a sparse array of
* virBitmaps named `masks` indexed the same way as `sizes`. The upper bounds
* of the sparse arrays are stored in nmasks or nsizes, respectively.
+ + *
+ * =====Memory Bandwidth allocation technology (MBA)=====
+ *
+ * The memory bandwidth allocation support in virResctrlAlloc works in the
+ * same fashion as CAT. However, memory bandwidth controller doesn't have a
+ * hierarchy organization as cache, each node have one memory bandwidth
+ * controller to memory bandwidth distribution. The number of memory bandwidth
+ * controller is identical with number of last level cache. So MBA also employs
+ * a sparse array to represent whether a memory bandwidth allocation happens
+ * on corresponding node. The available memory controller number is collected
+ * in 'virResctrlInfo'.
*/
struct _virResctrlAllocPerType {
/* There could be bool saying whether this is set or not, but since everything
@@ -225,12 +242,24 @@ struct _virResctrlAllocPerLevel {
* VIR_CACHE_TYPE_LAST number of items */
};
+/*
+ * virResctrlAllocMemBW represents one memory bandwidth allocation.
+ * Since it can have several last level caches in a NUMA system, it is
+ * also represented as a nested sparse arrays as virRestrlAllocPerLevel.
+ */
+struct _virResctrlAllocMemBW {
+ unsigned int **bandwidths;
+ size_t nbandwidths;
+};
+
struct _virResctrlAlloc {
virObject parent;
virResctrlAllocPerLevelPtr *levels;
size_t nlevels;
+ virResctrlAllocMemBWPtr mem_bw;
+
/* The identifier (any unique string for now) */
char *id;
/* libvirt-generated path in /sys/fs/resctrl for this particular
@@ -274,6 +303,13 @@ virResctrlAllocDispose(void *obj)
VIR_FREE(level);
}
+ if (alloc->mem_bw) {
+ virResctrlAllocMemBWPtr mem_bw = alloc->mem_bw;
+ for (i = 0; i < mem_bw->nbandwidths; i++)
+ VIR_FREE(mem_bw->bandwidths[i]);
+ VIR_FREE(alloc->mem_bw);
+ }
+
VIR_FREE(alloc->id);
VIR_FREE(alloc->path);
VIR_FREE(alloc->levels);
@@ -692,6 +728,9 @@ virResctrlAllocIsEmpty(virResctrlAllocPtr alloc)
if (!alloc)
return true;
+ if (alloc->mem_bw)
+ return false;
+
for (i = 0; i < alloc->nlevels; i++) {
virResctrlAllocPerLevelPtr a_level = alloc->levels[i];
@@ -1266,6 +1305,22 @@ virResctrlAllocNewFromInfo(virResctrlInfoPtr info)
}
}
+ /* set default free memory bandwidth to 100%*/
+ if (info->membw_info) {
+ if (VIR_ALLOC(ret->mem_bw) < 0)
+ goto error;
+
+ if (VIR_EXPAND_N(ret->mem_bw->bandwidths, ret->mem_bw->nbandwidths,
+ info->membw_info->max_id + 1) < 0)
+ goto error;
+
+ for (i = 0; i < ret->mem_bw->nbandwidths; i++) {
+ if (VIR_ALLOC(ret->mem_bw->bandwidths[i]) < 0)
+ goto error;
+ *(ret->mem_bw->bandwidths[i]) = 100;
+ }
+ }
+
cleanup:
virBitmapFree(mask);
return ret;
--
2.7.4