Changeset 45c8eea in mainline

Timestamp:

2018-11-11T15:47:39Z (6 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

f4cb6c5f

Parents:

269bc459

git-author:

Jakub Jermar <jakub@…> (2018-11-10 17:49:44)

git-committer:

Jakub Jermar <jakub@…> (2018-11-11 15:47:39)

Message:

Preallocate waitq handle during initialization

Do not clutter futex_down_composable() with the preallocation of the
wait queue handle and do it single-threadedly in futex_initialize().

Location:

uspace/lib/c

Files:

• generic/async/client.c (modified) (2 diffs)
• generic/async/ports.c (modified) (2 diffs)
• generic/async/server.c (modified) (2 diffs)
• generic/io/kio.c (modified) (2 diffs)
• generic/libc.c (modified) (3 diffs)
• generic/malloc.c (modified) (2 diffs)
• generic/private/fibril.h (modified) (1 diff)
• generic/private/futex.h (modified) (6 diffs)
• generic/thread/fibril.c (modified) (4 diffs)
• generic/thread/fibril_synch.c (modified) (2 diffs)
• generic/thread/futex.c (modified) (1 diff)
• generic/thread/mpsc.c (modified) (1 diff)
• include/fibril_synch.h (modified) (1 diff)
• include/io/kio.h (modified) (1 diff)

uspace/lib/c/generic/async/client.c

@@ -122 +122 @@
 #include "../private/fibril.h"
 
-static FIBRIL_RMUTEX_INITIALIZE(message_mutex);
+static fibril_rmutex_t message_mutex;
 
 /** Naming service session */
@@ -173 +173 @@
 void __async_client_init(void)
 {
+        if (fibril_rmutex_initialize(&message_mutex) != EOK)
+                abort();
+
         session_ns.iface = 0;
         session_ns.mgmt = EXCHANGE_ATOMIC;

uspace/lib/c/generic/async/ports.c

@@ -100 +100 @@
 
 /** Futex guarding the interface hash table. */
-static FIBRIL_RMUTEX_INITIALIZE(interface_mutex);
+static fibril_rmutex_t interface_mutex;
 static hash_table_t interface_hash_table;
 
@@ -292 +292 @@
 void __async_ports_init(void)
 {
+        if (fibril_rmutex_initialize(&interface_mutex) != EOK)
+                abort();
+
         if (!hash_table_create(&interface_hash_table, 0, 0,
             &interface_hash_table_ops))

uspace/lib/c/generic/async/server.c

@@ -216 +216 @@
 }
 
-static FIBRIL_RMUTEX_INITIALIZE(client_mutex);
+static fibril_rmutex_t client_mutex;
 static hash_table_t client_hash_table;
 
 // TODO: lockfree notification_queue?
-static FIBRIL_RMUTEX_INITIALIZE(notification_mutex);
+static fibril_rmutex_t notification_mutex;
 static hash_table_t notification_hash_table;
 static LIST_INITIALIZE(notification_queue);
@@ -1013 +1013 @@
 void __async_server_init(void)
 {
+        if (fibril_rmutex_initialize(&client_mutex) != EOK)
+                abort();
+        if (fibril_rmutex_initialize(&notification_mutex) != EOK)
+                abort();
+
         if (!hash_table_create(&client_hash_table, 0, 0, &client_hash_table_ops))
                 abort();

uspace/lib/c/generic/io/kio.c

@@ -38 +38 @@
 #include <str.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <abi/kio.h>
@@ -53 +54 @@
         char data[KIO_BUFFER_SIZE];
         size_t used;
-} kio_buffer = { .futex = FUTEX_INITIALIZER, };
+} kio_buffer;
+
+void __kio_init(void)
+{
+        if (futex_initialize(&kio_buffer.futex, 1) != EOK)
+                abort();
+}
 
 errno_t kio_write(const void *buf, size_t size, size_t *nwritten)

uspace/lib/c/generic/libc.c

@@ -40 +40 @@
 #include <tls.h>
 #include <fibril.h>
+#include <fibril_synch.h>
 #include <task.h>
 #include <loader/pcb.h>
 #include <vfs/vfs.h>
 #include <vfs/inbox.h>
+#include <io/kio.h>
 #include "private/libc.h"
 #include "private/async.h"
@@ -61 +63 @@
 void __libc_main(void *pcb_ptr)
 {
+        __kio_init();
+
         assert(!__tcb_is_set());
 
@@ -81 +85 @@
 
         __fibrils_init();
+        __fibril_synch_init();
 
         /* Initialize the fibril. */

uspace/lib/c/generic/malloc.c

@@ -195 +195 @@
 
 /** Futex for thread-safe heap manipulation */
-static FIBRIL_RMUTEX_INITIALIZE(malloc_mutex);
+static fibril_rmutex_t malloc_mutex;
 
 #define malloc_assert(expr) safe_assert(expr)
@@ -484 +484 @@
 void __malloc_init(void)
 {
+        if (fibril_rmutex_initialize(&malloc_mutex) != EOK)
+                abort();
+
         if (!area_create(PAGE_SIZE))
                 abort();

uspace/lib/c/generic/private/fibril.h

@@ -120 +120 @@
 } fibril_rmutex_t;
 
-#define FIBRIL_RMUTEX_INITIALIZER(name) \
-        { .futex = FUTEX_INITIALIZE(1) }
-
-#define FIBRIL_RMUTEX_INITIALIZE(name) \
-        fibril_rmutex_t name = FIBRIL_RMUTEX_INITIALIZER(name)
-
-extern void fibril_rmutex_initialize(fibril_rmutex_t *);
+extern errno_t fibril_rmutex_initialize(fibril_rmutex_t *);
 extern void fibril_rmutex_destroy(fibril_rmutex_t *);
 extern void fibril_rmutex_lock(fibril_rmutex_t *);

uspace/lib/c/generic/private/futex.h

@@ -46 +46 @@
 typedef struct futex {
         volatile atomic_int val;
-        volatile atomic_int lock;
         volatile cap_waitq_handle_t whandle;
 
@@ -54 +53 @@
 } futex_t;
 
-extern void futex_initialize(futex_t *futex, int value);
+extern errno_t futex_initialize(futex_t *futex, int value);
 
 static inline errno_t futex_destroy(futex_t *futex)
@@ -64 +63 @@
 
 #ifdef CONFIG_DEBUG_FUTEX
-
-#define FUTEX_INITIALIZE(val) { (val), 0, CAP_NIL, NULL }
-#define FUTEX_INITIALIZER     FUTEX_INITIALIZE(1)
 
 void __futex_assert_is_locked(futex_t *, const char *);
@@ -85 +81 @@
 #else
 
-#define FUTEX_INITIALIZE(val) { (val), 0, CAP_NIL }
-#define FUTEX_INITIALIZER     FUTEX_INITIALIZE(1)
-
 #define futex_lock(fut)     (void) futex_down((fut))
 #define futex_trylock(fut)  futex_trydown((fut))
@@ -98 +91 @@
 #endif
 
-static errno_t allocate_waitq(futex_t *futex)
-{
-        int expected = 0;
-        while (!atomic_compare_exchange_weak_explicit(&futex->lock, &expected,
-            1, memory_order_acquire, memory_order_relaxed))
-                expected = 0;
-
-        if (futex->whandle == CAP_NIL) {
-                errno_t rc = __SYSCALL1(SYS_WAITQ_CREATE,
-                    (sysarg_t) &futex->whandle);
-                if (rc != EOK) {
-                        atomic_store_explicit(&futex->lock, 0,
-                            memory_order_release);
-                        return rc;
-                }
-        }
-
-        atomic_store_explicit(&futex->lock, 0, memory_order_release);
-        return EOK;
+static inline errno_t futex_allocate_waitq(futex_t *futex)
+{
+        return __SYSCALL1(SYS_WAITQ_CREATE, (sysarg_t) &futex->whandle);
 }
 
@@ -140 +117 @@
         // TODO: Add tests for this.
 
-        // Preallocate the waitq handle so that we don't need to risk a failure
-        // during wakeup
-        if (futex->whandle == CAP_NIL) {
-                errno_t rc = allocate_waitq(futex);
-                if (rc != EOK)
-                        return rc;
-        }
+        assert(futex->whandle != CAP_NIL);
 
         if (atomic_fetch_sub_explicit(&futex->val, 1, memory_order_acquire) > 0)

uspace/lib/c/generic/thread/fibril.c

@@ -87 +87 @@
 
 /* This futex serializes access to global data. */
-static futex_t fibril_futex = FUTEX_INITIALIZER;
+static futex_t fibril_futex;
 static futex_t ready_semaphore;
 static long ready_st_count;
@@ -95 +95 @@
 static LIST_INITIALIZE(timeout_list);
 
-static futex_t ipc_lists_futex = FUTEX_INITIALIZER;
+static futex_t ipc_lists_futex;
 static LIST_INITIALIZE(ipc_waiter_list);
 static LIST_INITIALIZE(ipc_buffer_list);
@@ -796 +796 @@
         if (!multithreaded) {
                 _ready_debug_check();
-                futex_initialize(&ready_semaphore, ready_st_count);
+                if (futex_initialize(&ready_semaphore, ready_st_count) != EOK)
+                        abort();
                 multithreaded = true;
         }
@@ -861 +862 @@
 void __fibrils_init(void)
 {
+        if (futex_initialize(&fibril_futex, 1) != EOK)
+                abort();
+        if (futex_initialize(&ipc_lists_futex, 1) != EOK)
+                abort();
+
         /*
          * We allow a fixed, small amount of parallelism for IPC reads, but

uspace/lib/c/generic/thread/fibril_synch.c

@@ -51 +51 @@
 #include "../private/futex.h"
 
-void fibril_rmutex_initialize(fibril_rmutex_t *m)
-{
-        futex_initialize(&m->futex, 1);
+errno_t fibril_rmutex_initialize(fibril_rmutex_t *m)
+{
+        return futex_initialize(&m->futex, 1);
 }
 
@@ -90 +90 @@
 static fibril_local bool deadlocked = false;
 
-static futex_t fibril_synch_futex = FUTEX_INITIALIZER;
+static futex_t fibril_synch_futex;
+
+void __fibril_synch_init(void)
+{
+        if (futex_initialize(&fibril_synch_futex, 1) != EOK)
+                abort();
+}
 
 typedef struct {

uspace/lib/c/generic/thread/futex.c

@@ -49 +49 @@
  * @param val   Initialization value.
  *
+ * @return      Error code.
  */
-void futex_initialize(futex_t *futex, int val)
+errno_t futex_initialize(futex_t *futex, int val)
 {
         atomic_store_explicit(&futex->val, val, memory_order_relaxed);
-        atomic_store_explicit(&futex->lock, 0, memory_order_relaxed);
         futex->whandle = CAP_NIL;
+        return futex_allocate_waitq(futex);
 }
 

uspace/lib/c/generic/thread/mpsc.c

@@ -80 +80 @@
         }
 
+        if (fibril_rmutex_initialize(&q->t_lock) != EOK) {
+                free(q);
+                free(n);
+                free(c);
+                return NULL;
+        }
+
         q->elem_size = elem_size;
-        fibril_rmutex_initialize(&q->t_lock);
         q->head = q->tail = n;
         q->close_node = c;

uspace/lib/c/include/fibril_synch.h

@@ -164 +164 @@
         fibril_semaphore_t name = FIBRIL_SEMAPHORE_INITIALIZER(name, cnt)
 
+extern void __fibril_synch_init(void);
+
 extern void fibril_mutex_initialize(fibril_mutex_t *);
 extern void fibril_mutex_lock(fibril_mutex_t *);

uspace/lib/c/include/io/kio.h

@@ -42 +42 @@
 #include <_bits/size_t.h>
 
+extern void __kio_init(void);
 extern errno_t kio_write(const void *, size_t, size_t *);
 extern void kio_update(void);