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authorIlya Dryomov <idryomov@gmail.com>2017-01-31 17:55:06 +0300
committerIlya Dryomov <idryomov@gmail.com>2017-02-20 14:16:11 +0300
commit66a0e2d579dbec5c676cfe446234ffebb267c564 (patch)
tree6a2d4307be3e39e4955697a49ed5daf6ea97d927 /include/linux/crush
parent1b6a78b5b91cdc07cc0b940b458e90c86835cf73 (diff)
downloadlinux-66a0e2d579dbec5c676cfe446234ffebb267c564.tar.xz
crush: remove mutable part of CRUSH map
Then add it to the working state. It would be very nice if we didn't have to take a lock to calculate a crush placement. By moving the permutation array into the working data, we can treat the CRUSH map as immutable. Reflects ceph.git commit cbcd039651c0569551cb90d26ce27e1432671f2a. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'include/linux/crush')
-rw-r--r--include/linux/crush/crush.h41
-rw-r--r--include/linux/crush/mapper.h4
2 files changed, 37 insertions, 8 deletions
diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h
index be8f12b8f195..fbecbd089d75 100644
--- a/include/linux/crush/crush.h
+++ b/include/linux/crush/crush.h
@@ -135,13 +135,6 @@ struct crush_bucket {
__u32 size; /* num items */
__s32 *items;
- /*
- * cached random permutation: used for uniform bucket and for
- * the linear search fallback for the other bucket types.
- */
- __u32 perm_x; /* @x for which *perm is defined */
- __u32 perm_n; /* num elements of *perm that are permuted/defined */
- __u32 *perm;
};
struct crush_bucket_uniform {
@@ -211,6 +204,21 @@ struct crush_map {
* device fails. */
__u8 chooseleaf_stable;
+ /*
+ * This value is calculated after decode or construction by
+ * the builder. It is exposed here (rather than having a
+ * 'build CRUSH working space' function) so that callers can
+ * reserve a static buffer, allocate space on the stack, or
+ * otherwise avoid calling into the heap allocator if they
+ * want to. The size of the working space depends on the map,
+ * while the size of the scratch vector passed to the mapper
+ * depends on the size of the desired result set.
+ *
+ * Nothing stops the caller from allocating both in one swell
+ * foop and passing in two points, though.
+ */
+ size_t working_size;
+
#ifndef __KERNEL__
/*
* version 0 (original) of straw_calc has various flaws. version 1
@@ -248,4 +256,23 @@ static inline int crush_calc_tree_node(int i)
return ((i+1) << 1)-1;
}
+/*
+ * These data structures are private to the CRUSH implementation. They
+ * are exposed in this header file because builder needs their
+ * definitions to calculate the total working size.
+ *
+ * Moving this out of the crush map allow us to treat the CRUSH map as
+ * immutable within the mapper and removes the requirement for a CRUSH
+ * map lock.
+ */
+struct crush_work_bucket {
+ __u32 perm_x; /* @x for which *perm is defined */
+ __u32 perm_n; /* num elements of *perm that are permuted/defined */
+ __u32 *perm; /* Permutation of the bucket's items */
+};
+
+struct crush_work {
+ struct crush_work_bucket **work; /* Per-bucket working store */
+};
+
#endif
diff --git a/include/linux/crush/mapper.h b/include/linux/crush/mapper.h
index 5dfd5b1125d2..3303c7fd8a31 100644
--- a/include/linux/crush/mapper.h
+++ b/include/linux/crush/mapper.h
@@ -15,6 +15,8 @@ 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,
- int *scratch);
+ void *cwin, int *scratch);
+
+void crush_init_workspace(const struct crush_map *map, void *v);
#endif