fs/jffs2/background.c

Source file repositories/reference/linux-study-clean/fs/jffs2/background.c

File Facts

System
Linux kernel
Corpus path
fs/jffs2/background.c
Extension
.c
Size
4333 bytes
Lines
166
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!jffs2_thread_should_wake(c)) {
			set_current_state (TASK_INTERRUPTIBLE);
			spin_unlock(&c->erase_completion_lock);
			jffs2_dbg(1, "%s(): sleeping...\n", __func__);
			schedule();
		} else {
			spin_unlock(&c->erase_completion_lock);
		}
		/* Problem - immediately after bootup, the GCD spends a lot
		 * of time in places like jffs2_kill_fragtree(); so much so
		 * that userspace processes (like gdm and X) are starved
		 * despite plenty of cond_resched()s and renicing.  Yield()
		 * doesn't help, either (presumably because userspace and GCD
		 * are generally competing for a higher latency resource -
		 * disk).
		 * This forces the GCD to slow the hell down.   Pulling an
		 * inode in with read_inode() is much preferable to having
		 * the GC thread get there first. */
		schedule_timeout_interruptible(msecs_to_jiffies(50));

		if (kthread_should_stop()) {
			jffs2_dbg(1, "%s(): kthread_stop() called\n", __func__);
			goto die;
		}

		/* Put_super will send a SIGKILL and then wait on the sem.
		 */
		while (signal_pending(current) || freezing(current)) {
			unsigned long signr;

			if (try_to_freeze())
				goto again;

			signr = kernel_dequeue_signal();

			switch(signr) {
			case SIGSTOP:
				jffs2_dbg(1, "%s(): SIGSTOP received\n",
					  __func__);
				kernel_signal_stop();
				break;

			case SIGKILL:
				jffs2_dbg(1, "%s(): SIGKILL received\n",
					  __func__);
				goto die;

			case SIGHUP:
				jffs2_dbg(1, "%s(): SIGHUP received\n",
					  __func__);
				break;
			default:
				jffs2_dbg(1, "%s(): signal %ld received\n",
					  __func__, signr);
			}
		}
		/* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
		sigprocmask(SIG_BLOCK, &hupmask, NULL);

		jffs2_dbg(1, "%s(): pass\n", __func__);
		if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
			pr_notice("No space for garbage collection. Aborting GC thread\n");
			goto die;
		}
	}
 die:
	spin_lock(&c->erase_completion_lock);
	c->gc_task = NULL;
	spin_unlock(&c->erase_completion_lock);
	kthread_complete_and_exit(&c->gc_thread_exit, 0);
}

Annotation

Implementation Notes