Changeset 8119363 in mainline for uspace/lib/c/generic/rcu.c

Timestamp:

2018-06-26T17:35:40Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

6e569bf

Parents:

fbfe59d (diff), e768aea (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge some preliminary async/fibril framework changes.

File:

• uspace/lib/c/generic/rcu.c (modified) (14 diffs)

uspace/lib/c/generic/rcu.c

@@ -82 +82 @@
 #include <thread.h>
 
+#include "private/fibril.h"
+
 
 /** RCU sleeps for RCU_SLEEP_MS before polling an active RCU reader again. */
@@ -148 +150 @@
 
 
-static void wait_for_readers(size_t reader_group, blocking_mode_t blocking_mode);
+static void wait_for_readers(size_t reader_group);
 static void force_mb_in_all_threads(void);
 static bool is_preexisting_reader(const fibril_rcu_data_t *fib, size_t group);
 
-static void lock_sync(blocking_mode_t blocking_mode);
+static void lock_sync(void);
 static void unlock_sync(void);
-static void sync_sleep(blocking_mode_t blocking_mode);
+static void sync_sleep(void);
 
 static bool is_in_group(size_t nesting_cnt, size_t group);
@@ -170 +172 @@
         assert(!fibril_rcu.registered);
 
-        futex_down(&rcu.list_futex);
+        futex_lock(&rcu.list_futex);
         list_append(&fibril_rcu.link, &rcu.fibrils_list);
-        futex_up(&rcu.list_futex);
+        futex_unlock(&rcu.list_futex);
 
         fibril_rcu.registered = true;
@@ -195 +197 @@
         fibril_rcu.nesting_cnt = 0;
 
-        futex_down(&rcu.list_futex);
+        futex_lock(&rcu.list_futex);
         list_remove(&fibril_rcu.link);
-        futex_up(&rcu.list_futex);
+        futex_unlock(&rcu.list_futex);
 
         fibril_rcu.registered = false;
@@ -240 +242 @@
 
 /** Blocks until all preexisting readers exit their critical sections. */
-void _rcu_synchronize(blocking_mode_t blocking_mode)
+void rcu_synchronize(void)
 {
         assert(!rcu_read_locked());
@@ -250 +252 @@
         size_t gp_in_progress = ACCESS_ONCE(rcu.cur_gp);
 
-        lock_sync(blocking_mode);
+        lock_sync();
 
         /*
@@ -298 +300 @@
 
         size_t new_reader_group = get_other_group(rcu.reader_group);
-        wait_for_readers(new_reader_group, blocking_mode);
+        wait_for_readers(new_reader_group);
 
         /* Separates waiting for readers in new_reader_group from group flip. */
@@ -310 +312 @@
         memory_barrier();
 
-        wait_for_readers(old_reader_group, blocking_mode);
+        wait_for_readers(old_reader_group);
 
         /* MB_FORCE_U  */
@@ -330 +332 @@
 
 /** Waits for readers of reader_group to exit their readers sections. */
-static void wait_for_readers(size_t reader_group, blocking_mode_t blocking_mode)
-{
-        futex_down(&rcu.list_futex);
+static void wait_for_readers(size_t reader_group)
+{
+        futex_lock(&rcu.list_futex);
 
         list_t quiescent_fibrils;
@@ -343 +345 @@
 
                         if (is_preexisting_reader(fib, reader_group)) {
-                                futex_up(&rcu.list_futex);
-                                sync_sleep(blocking_mode);
-                                futex_down(&rcu.list_futex);
+                                futex_unlock(&rcu.list_futex);
+                                sync_sleep();
+                                futex_lock(&rcu.list_futex);
                                 /* Break to while loop. */
                                 break;
@@ -356 +358 @@
 
         list_concat(&rcu.fibrils_list, &quiescent_fibrils);
-        futex_up(&rcu.list_futex);
-}
-
-static void lock_sync(blocking_mode_t blocking_mode)
-{
-        futex_down(&rcu.sync_lock.futex);
+        futex_unlock(&rcu.list_futex);
+}
+
+static void lock_sync(void)
+{
+        futex_lock(&rcu.sync_lock.futex);
         if (rcu.sync_lock.locked) {
-                if (blocking_mode == BM_BLOCK_FIBRIL) {
-                        blocked_fibril_t blocked_fib;
-                        blocked_fib.id = fibril_get_id();
-
-                        list_append(&blocked_fib.link, &rcu.sync_lock.blocked_fibrils);
-
-                        do {
-                                blocked_fib.is_ready = false;
-                                futex_up(&rcu.sync_lock.futex);
-                                fibril_switch(FIBRIL_TO_MANAGER);
-                                futex_down(&rcu.sync_lock.futex);
-                        } while (rcu.sync_lock.locked);
-
-                        list_remove(&blocked_fib.link);
-                        rcu.sync_lock.locked = true;
-                } else {
-                        assert(blocking_mode == BM_BLOCK_THREAD);
-                        rcu.sync_lock.blocked_thread_cnt++;
-                        futex_up(&rcu.sync_lock.futex);
-                        futex_down(&rcu.sync_lock.futex_blocking_threads);
-                }
+                blocked_fibril_t blocked_fib;
+                blocked_fib.id = fibril_get_id();
+
+                list_append(&blocked_fib.link, &rcu.sync_lock.blocked_fibrils);
+
+                do {
+                        blocked_fib.is_ready = false;
+                        futex_unlock(&rcu.sync_lock.futex);
+                        futex_lock(&async_futex);
+                        fibril_switch(FIBRIL_FROM_BLOCKED);
+                        futex_unlock(&async_futex);
+                        futex_lock(&rcu.sync_lock.futex);
+                } while (rcu.sync_lock.locked);
+
+                list_remove(&blocked_fib.link);
+                rcu.sync_lock.locked = true;
         } else {
                 rcu.sync_lock.locked = true;
@@ -399 +396 @@
         if (0 < rcu.sync_lock.blocked_thread_cnt) {
                 --rcu.sync_lock.blocked_thread_cnt;
-                futex_up(&rcu.sync_lock.futex_blocking_threads);
+                futex_unlock(&rcu.sync_lock.futex_blocking_threads);
         } else {
                 /* Unlock but wake up any fibrils waiting for the lock. */
@@ -414 +411 @@
 
                 rcu.sync_lock.locked = false;
-                futex_up(&rcu.sync_lock.futex);
+                futex_unlock(&rcu.sync_lock.futex);
         }
 }
 
-static void sync_sleep(blocking_mode_t blocking_mode)
+static void sync_sleep(void)
 {
         assert(rcu.sync_lock.locked);
@@ -425 +422 @@
          * but keep sync locked.
          */
-        futex_up(&rcu.sync_lock.futex);
-
-        if (blocking_mode == BM_BLOCK_FIBRIL) {
-                async_usleep(RCU_SLEEP_MS * 1000);
-        } else {
-                thread_usleep(RCU_SLEEP_MS * 1000);
-        }
-
-        futex_down(&rcu.sync_lock.futex);
+        futex_unlock(&rcu.sync_lock.futex);
+        async_usleep(RCU_SLEEP_MS * 1000);
+        futex_lock(&rcu.sync_lock.futex);
 }