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authorJustus Winter <4winter@informatik.uni-hamburg.de>2014-05-03 03:53:41 +0200
committerJustus Winter <4winter@informatik.uni-hamburg.de>2014-09-29 17:03:57 +0200
commitb2ae574d39adfe283c61a3ec0c766e8780f345af (patch)
tree994d77346507f28b621a4a573f87f1f1e890e097 /libports/claim-right.c
parent02c47da17b716bfff20bfafe2d5958b2b720ff49 (diff)
libports: use a global hash table for the lookups
Previously, libports used a hash table per port bucket. This makes looking up a port difficult if one does not know the port bucket, as one has to iterate over all buckets and do a hash table lookup each. Having to iterate over the buckets makes it necessary to keep a list of all buckets, which has to be updated and protected by a lock as well. Also, the current code in _ports_bucket_class_iterate iterates over the hash table associated with the bucket given. When ports_class_iterate calls this common function, it obtains a reference to the bucket from one of the ports in the given class. This will not work if a class contains ports in different port buckets. This limitation is not documented as far as I can see. Again, having to maintain this list has its cost and requires serialization. Use a global hash table for lookups instead. Keep the per-bucket hash tables for efficient iteration over buckets. Furthermore, serialize access to all hash tables using a separate lock. Remove the linked lists of all buckets and all ports in a class. * libports/bucket-iterate.c (ports_bucket_iterate): Acquire _ports_htable_lock. Also, generalize ports_bucket_iterate so that it takes a pointer to a hash table as first argument. (ports_bucket_iterate): Ajust call to former function accordingly. * libports/class-iterate.c (ports_class_iterate): Just call the generalized _ports_bucket_class_iterate with the global hash table as argument. * libports/ports.h (struct port_info): Remove the port class links. (struct port_bucket): Remove the hash table, and the all buckets link. (_ports_all_buckets): Remove declaration. (_ports_htable): New global hash table. (_ports_htable_lock): Protected by this lock. * libports/claim-right.c: Adjust accordingly. * libports/complete-deallocate.c: Likewise. * libports/create-bucket.c: Likewise. * libports/create-class.c: Likewise. * libports/create-internal.c: Likewise. * libports/destroy-right.c: Likewise. * libports/import-port.c: Likewise. * libports/lookup-port.c: Likewise. * libports/reallocate-from-external.c: Likewise. * libports/reallocate-port.c: Likewise. * libports/transfer-right.c: Likewise. * libports/inhibit-all-rpcs.c: Iterate over the hash table. * libports/inhibit-bucket-rpcs.c: Likewise, but filter using bucket. * libports/inhibit-class-rpcs.c: Likewise, but filter using class. * libports/init.c (_ports_htable): Initialize. (_ports_htable_lock): Likewise.
Diffstat (limited to 'libports/claim-right.c')
-rw-r--r--libports/claim-right.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/libports/claim-right.c b/libports/claim-right.c
index 4851ea3c..85592ff0 100644
--- a/libports/claim-right.c
+++ b/libports/claim-right.c
@@ -34,10 +34,13 @@ ports_claim_right (void *portstruct)
if (ret == MACH_PORT_NULL)
return ret;
- pthread_mutex_lock (&_ports_lock);
+ pthread_rwlock_wrlock (&_ports_htable_lock);
+ hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+ pthread_rwlock_unlock (&_ports_htable_lock);
err = mach_port_move_member (mach_task_self (), ret, MACH_PORT_NULL);
assert_perror (err);
+ pthread_mutex_lock (&_ports_lock);
pi->port_right = MACH_PORT_NULL;
if (pi->flags & PORT_HAS_SENDRIGHTS)
{