diff options
Diffstat (limited to 'fs/jffs2/background.c')
| -rw-r--r-- | fs/jffs2/background.c | 81 |
1 files changed, 50 insertions, 31 deletions
diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c index 8adebd3e43c..bb9cebc9ca8 100644 --- a/fs/jffs2/background.c +++ b/fs/jffs2/background.c @@ -2,6 +2,7 @@ * JFFS2 -- Journalling Flash File System, Version 2. * * Copyright © 2001-2007 Red Hat, Inc. + * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org> * * Created by David Woodhouse <dwmw2@infradead.org> * @@ -9,12 +10,15 @@ * */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/kernel.h> #include <linux/jffs2.h> #include <linux/mtd/mtd.h> #include <linux/completion.h> #include <linux/sched.h> #include <linux/freezer.h> +#include <linux/kthread.h> #include "nodelist.h" @@ -22,16 +26,15 @@ static int jffs2_garbage_collect_thread(void *); void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c) { - spin_lock(&c->erase_completion_lock); + assert_spin_locked(&c->erase_completion_lock); if (c->gc_task && jffs2_thread_should_wake(c)) send_sig(SIGHUP, c->gc_task, 1); - spin_unlock(&c->erase_completion_lock); } /* This must only ever be called when no GC thread is currently running */ int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) { - pid_t pid; + struct task_struct *tsk; int ret = 0; BUG_ON(c->gc_task); @@ -39,15 +42,17 @@ int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) init_completion(&c->gc_thread_start); init_completion(&c->gc_thread_exit); - pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES); - if (pid < 0) { - printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid); + tsk = kthread_run(jffs2_garbage_collect_thread, c, "jffs2_gcd_mtd%d", c->mtd->index); + if (IS_ERR(tsk)) { + pr_warn("fork failed for JFFS2 garbage collect thread: %ld\n", + -PTR_ERR(tsk)); complete(&c->gc_thread_exit); - ret = pid; + ret = PTR_ERR(tsk); } else { /* Wait for it... */ - D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid)); + jffs2_dbg(1, "Garbage collect thread is pid %d\n", tsk->pid); wait_for_completion(&c->gc_thread_start); + ret = tsk->pid; } return ret; @@ -58,7 +63,7 @@ void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) int wait = 0; spin_lock(&c->erase_completion_lock); if (c->gc_task) { - D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid)); + jffs2_dbg(1, "Killing GC task %d\n", c->gc_task->pid); send_sig(SIGKILL, c->gc_task, 1); wait = 1; } @@ -70,11 +75,13 @@ void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) static int jffs2_garbage_collect_thread(void *_c) { struct jffs2_sb_info *c = _c; + sigset_t hupmask; - daemonize("jffs2_gcd_mtd%d", c->mtd->index); + siginitset(&hupmask, sigmask(SIGHUP)); allow_signal(SIGKILL); allow_signal(SIGSTOP); allow_signal(SIGCONT); + allow_signal(SIGHUP); c->gc_task = current; complete(&c->gc_thread_start); @@ -83,25 +90,33 @@ static int jffs2_garbage_collect_thread(void *_c) set_freezable(); for (;;) { - allow_signal(SIGHUP); + sigprocmask(SIG_UNBLOCK, &hupmask, NULL); again: + spin_lock(&c->erase_completion_lock); if (!jffs2_thread_should_wake(c)) { set_current_state (TASK_INTERRUPTIBLE); - D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n")); - /* Yes, there's a race here; we checked jffs2_thread_should_wake() - before setting current->state to TASK_INTERRUPTIBLE. But it doesn't - matter - We don't care if we miss a wakeup, because the GC thread - is only an optimisation anyway. */ + 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; } - - /* This thread is purely an optimisation. But if it runs when - other things could be running, it actually makes things a - lot worse. Use yield() and put it at the back of the runqueue - every time. Especially during boot, pulling an inode in - with read_inode() is much preferable to having the GC thread - get there first. */ - yield(); /* Put_super will send a SIGKILL and then wait on the sem. */ @@ -116,28 +131,32 @@ static int jffs2_garbage_collect_thread(void *_c) switch(signr) { case SIGSTOP: - D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n")); + jffs2_dbg(1, "%s(): SIGSTOP received\n", + __func__); set_current_state(TASK_STOPPED); schedule(); break; case SIGKILL: - D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n")); + jffs2_dbg(1, "%s(): SIGKILL received\n", + __func__); goto die; case SIGHUP: - D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n")); + jffs2_dbg(1, "%s(): SIGHUP received\n", + __func__); break; default: - D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr)); + jffs2_dbg(1, "%s(): signal %ld received\n", + __func__, signr); } } /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ - disallow_signal(SIGHUP); + sigprocmask(SIG_BLOCK, &hupmask, NULL); - D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n")); + jffs2_dbg(1, "%s(): pass\n", __func__); if (jffs2_garbage_collect_pass(c) == -ENOSPC) { - printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n"); + pr_notice("No space for garbage collection. Aborting GC thread\n"); goto die; } } |