ComputerSurge/bind9
3
0
Fork 0
Code Pull Requests 1 Activity

add comments, move color to avoid locking problem

Browse Source
This commit is contained in:
Bob Halley
1999-02-10 19:05:40 +00:00
parent fd350b6d2a
commit cd9999a958
1 changed files with 15 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
lib/dns/include/dns/rbt.h
View File

@@ -31,17 +31,29 @@
typedef struct dns_rbt dns_rbt_t;
/* These should add up to 30 */
/* These should add up to 31 */
#define DNS_RBT_LOCKLENGTH 10
#define DNS_RBT_LOCKLENGTH 11
#define DNS_RBT_REFLENGTH 20
typedef struct dns_rbt_node {
struct dns_rbt_node *left;
struct dns_rbt_node *right;
struct dns_rbt_node *down;
/*
* We'd like to find a better place for the single bit of color
* information. We can't pack it into the bitfield below, however,
* because it's not covered by the node lock, and changing a single
* bit in a bitfield is going to require a read-modify-write of a
* word. This read-modify-write would include bits covered by a
* lock we don't hold, and thus violate locking.
*/
unsigned int color;
/*
* These values are used in the RBT DB implementation. The appropriate
* node lock must be held before accessing them.
*/
void *data;
unsigned int color:1;
unsigned int dirty:1;
unsigned int locknum:DNS_RBT_LOCKLENGTH;
unsigned int references:DNS_RBT_REFLENGTH;