Create per-thread task for dns_adb resolver fetches

The dns_adb would serialize all fetches on a single task.  Create a
per-thread task, so the fetches will stay local to the thread that
initiated the fetch.

diff --git a/lib/dns/adb.c b/lib/dns/adb.c
index 467131696b069fcee390df29de8cc3e8effa9b33..0f1c7c62e0d42e0ed6e9468e9b82dafb3ac5195d 100644 (file)
--- a/lib/dns/adb.c
+++ b/lib/dns/adb.c
@@ -26,6 +26,7 @@
 
 #include <isc/atomic.h>
 #include <isc/hashmap.h>
+#include <isc/loop.h>
 #include <isc/mutexblock.h>
 #include <isc/netaddr.h>
 #include <isc/print.h>
@@ -34,6 +35,7 @@
 #include <isc/stats.h>
 #include <isc/string.h>
 #include <isc/task.h>
+#include <isc/tid.h>
 #include <isc/util.h>
 
 #include <dns/adb.h>
@@ -110,9 +112,10 @@ struct dns_adb {
        isc_mem_t *mctx;
        dns_view_t *view;
        dns_resolver_t *res;
+       size_t nloops;
 
        isc_taskmgr_t *taskmgr;
-       isc_task_t *task;
+       isc_task_t **tasks;
 
        isc_refcount_t references;
 
@@ -2032,7 +2035,11 @@ destroy(dns_adb_t *adb) {
        isc_mutex_destroy(&adb->lock);
        isc_refcount_destroy(&adb->references);
 
-       isc_task_detach(&adb->task);
+       for (size_t i = 0; i < adb->nloops; i++) {
+               isc_task_detach(&adb->tasks[i]);
+       }
+       isc_mem_put(adb->mctx, adb->tasks, adb->nloops * sizeof(adb->tasks[0]));
+
        isc_stats_detach(&adb->stats);
        dns_resolver_detach(&adb->res);
        dns_view_weakdetach(&adb->view);
@@ -2044,8 +2051,8 @@ destroy(dns_adb_t *adb) {
  */
 
 isc_result_t
-dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_taskmgr_t *taskmgr,
-              dns_adb_t **newadb) {
+dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_loopmgr_t *loopmgr,
+              isc_taskmgr_t *taskmgr, dns_adb_t **newadb) {
        dns_adb_t *adb = NULL;
        isc_result_t result;
 
@@ -2057,6 +2064,7 @@ dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_taskmgr_t *taskmgr,
        adb = isc_mem_get(mem, sizeof(dns_adb_t));
        *adb = (dns_adb_t){
                .taskmgr = taskmgr,
+               .nloops = isc_loopmgr_nloops(loopmgr),
        };
 
        /*
@@ -2083,16 +2091,19 @@ dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_taskmgr_t *taskmgr,
        /*
         * Allocate an internal task.
         */
-       result = isc_task_create(adb->taskmgr, &adb->task, 0);
-       if (result != ISC_R_SUCCESS) {
-               goto free_lock;
+       adb->tasks = isc_mem_getx(
+               adb->mctx, adb->nloops * sizeof(adb->tasks[0]), ISC_MEM_ZERO);
+       for (size_t i = 0; i < adb->nloops; i++) {
+               result = isc_task_create(adb->taskmgr, &adb->tasks[i], i);
+               if (result != ISC_R_SUCCESS) {
+                       goto free_tasks;
+               }
+               isc_task_setname(adb->tasks[i], "ADB", adb);
        }
 
-       isc_task_setname(adb->task, "ADB", adb);
-
        result = isc_stats_create(adb->mctx, &adb->stats, dns_adbstats_max);
        if (result != ISC_R_SUCCESS) {
-               goto free_task;
+               goto free_tasks;
        }
 
        set_adbstat(adb, isc_hashmap_count(adb->namebuckets),
@@ -2107,10 +2118,14 @@ dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_taskmgr_t *taskmgr,
        *newadb = adb;
        return (ISC_R_SUCCESS);
 
-free_task:
-       isc_task_detach(&adb->task);
+free_tasks:
+       for (size_t i = 0; i < adb->nloops; i++) {
+               if (adb->tasks[i] != NULL) {
+                       isc_task_detach(&adb->tasks[i]);
+               }
+       }
+       isc_mem_put(adb->mctx, adb->tasks, adb->nloops * sizeof(adb->tasks[0]));
 
-free_lock:
        isc_mutex_destroy(&adb->lock);
 
        isc_rwlock_destroy(&adb->entries_lock);
@@ -3313,6 +3328,7 @@ fetch_name(dns_adbname_t *adbname, bool start_at_zone, unsigned int depth,
        dns_rdataset_t rdataset;
        dns_rdataset_t *nameservers = NULL;
        unsigned int options;
+       uint32_t tid = isc_tid();
 
        REQUIRE(DNS_ADBNAME_VALID(adbname));
 
@@ -3354,7 +3370,7 @@ fetch_name(dns_adbname_t *adbname, bool start_at_zone, unsigned int depth,
         */
        result = dns_resolver_createfetch(
                adb->res, &adbname->name, type, name, nameservers, NULL, NULL,
-               0, options, depth, qc, adb->task, fetch_callback, adbname,
+               0, options, depth, qc, adb->tasks[tid], fetch_callback, adbname,
                &fetch->rdataset, NULL, &fetch->fetch);
        if (result != ISC_R_SUCCESS) {
                DP(ENTER_LEVEL, "fetch_name: createfetch failed with %s",
@@ -3911,11 +3927,12 @@ water(void *arg, int mark) {
        bool overmem = (mark == ISC_MEM_HIWATER);
 
        /*
-        * We're going to change the way to handle overmem condition: use
-        * isc_mem_isovermem() instead of storing the state via this callback,
-        * since the latter way tends to cause race conditions.
-        * To minimize the change, and in case we re-enable the callback
-        * approach, however, keep this function at the moment.
+        * We're going to change the way to handle overmem condition:
+        * use isc_mem_isovermem() instead of storing the state via this
+        * callback, since the latter way tends to cause race
+        * conditions. To minimize the change, and in case we re-enable
+        * the callback approach, however, keep this function at the
+        * moment.
         */
 
        REQUIRE(DNS_ADB_VALID(adb));

diff --git a/lib/dns/include/dns/adb.h b/lib/dns/include/dns/adb.h
index 1daa6b8e08d42bdbeb974a6de071c7f6eb2c4f93..524f669f2d989f5650242ddbb2e72a1311b1545f 100644 (file)
--- a/lib/dns/include/dns/adb.h
+++ b/lib/dns/include/dns/adb.h
@@ -255,8 +255,8 @@ struct dns_adbaddrinfo {
 ****/
 
 isc_result_t
-dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_taskmgr_t *taskmgr,
-              dns_adb_t **newadb);
+dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_loopmgr_t *loopmgr,
+              isc_taskmgr_t *taskmgr, dns_adb_t **newadb);
 /*%<
  * Create a new ADB.
  *

diff --git a/lib/dns/view.c b/lib/dns/view.c
index 89f41f7edc666248016407f01d07864392e26dad..bd0af302bddfbd916e7590bfcda3e51b59d9cf6e 100644 (file)
--- a/lib/dns/view.c
+++ b/lib/dns/view.c
@@ -681,7 +681,7 @@ dns_view_createresolver(dns_view_t *view, isc_loopmgr_t *loopmgr,
 
        isc_mem_create(&mctx);
        isc_mem_setname(mctx, "ADB");
-       result = dns_adb_create(mctx, view, taskmgr, &view->adb);
+       result = dns_adb_create(mctx, view, loopmgr, taskmgr, &view->adb);
        isc_mem_detach(&mctx);
        if (result != ISC_R_SUCCESS) {
                goto cleanup_resolver;