From: Adam C. Emerson <aemerson@redhat.com>
Date: Thu, 15 Sep 2016 15:33:30 +0000 (-0400)
Subject: crush: Merge working data and scratch
X-Git-Tag: v11.1.0~328^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=95c2df6c7e0b22d2ea9d91db500cf8b9441c73ba;p=ceph.git

crush: Merge working data and scratch

Much like Arlo Guthrie, I decided that one big pile is better than two
little piles.

Signed-off-by: Adam C. Emerson <aemerson@redhat.com>
---

diff --git a/src/crush/CrushWrapper.h b/src/crush/CrushWrapper.h
index 36013321aa25..059872c6cbb3 100644
--- a/src/crush/CrushWrapper.h
+++ b/src/crush/CrushWrapper.h
@@ -1090,11 +1090,10 @@ public:
 	       const vector<__u32>& weight) const {
     Mutex::Locker l(mapper_lock);
     int rawout[maxout];
-    int scratch[maxout * 3];
-    char work[crush->working_size];
+    char work[crush_work_size(crush, maxout)];
     crush_init_workspace(crush, work);
     int numrep = crush_do_rule(crush, rule, x, rawout, maxout, &weight[0],
-			       weight.size(), work, scratch);
+			       weight.size(), work);
     if (numrep < 0)
       numrep = 0;
     out.resize(numrep);
diff --git a/src/crush/mapper.c b/src/crush/mapper.c
index 4d37e0e9829f..d2417e52a37a 100644
--- a/src/crush/mapper.c
+++ b/src/crush/mapper.c
@@ -23,6 +23,7 @@
 # include "hash.h"
 #endif
 #include "crush_ln_table.h"
+#include "mapper.h"
 
 #define dprintk(args...) /* printf(args) */
 
@@ -851,22 +852,21 @@ void crush_init_workspace(const struct crush_map *m, void *v) {
  * @weight: weight vector (for map leaves)
  * @weight_max: size of weight vector
  * @cwin: Pointer to at least map->working_size bytes of memory or NULL.
- * @scratch: scratch vector for private use; must be >= 3 * result_max
  */
 int crush_do_rule(const struct crush_map *map,
 		  int ruleno, int x, int *result, int result_max,
 		  const __u32 *weight, int weight_max,
-		  void *cwin, int *scratch)
+		  void *cwin)
 {
 	int result_len;
 	struct crush_work *cw = cwin;
-	int *a = scratch;
-	int *b = scratch + result_max;
-	int *c = scratch + result_max*2;
+	int *a = (int *)((char *)cw + map->working_size);
+	int *b = a + result_max;
+	int *c = b + result_max;
+	int *w = a;
+	int *o = b;
 	int recurse_to_leaf;
-	int *w;
 	int wsize = 0;
-	int *o;
 	int osize;
 	int *tmp;
 	const struct crush_rule *rule;
@@ -897,9 +897,6 @@ int crush_do_rule(const struct crush_map *map,
 
 	rule = map->rules[ruleno];
 	result_len = 0;
-	w = a;
-	o = b;
-
 
 	for (step = 0; step < rule->len; step++) {
 		int firstn = 0;
diff --git a/src/crush/mapper.h b/src/crush/mapper.h
index 0b0f05e0cdc6..b9a614d1476d 100644
--- a/src/crush/mapper.h
+++ b/src/crush/mapper.h
@@ -15,7 +15,17 @@ extern int crush_do_rule(const struct crush_map *map,
 			 int ruleno,
 			 int x, int *result, int result_max,
 			 const __u32 *weights, int weight_max,
-			 void *cwin, int *scratch);
+			 void *cwin);
+
+/* Returns the exact amount of workspace that will need to be used
+   for a given combination of crush_map and result_max. The caller can
+   then allocate this much on its own, either on the stack, in a
+   per-thread long-lived buffer, or however it likes. */
+
+static inline size_t crush_work_size(const struct crush_map *map,
+				     int result_max) {
+	return map->working_size + result_max * 3 * sizeof(__u32);
+}
 
 extern void crush_init_workspace(const struct crush_map *m, void *v);