diff options
| -rw-r--r-- | mm/backing-dev.c | 69 |
1 files changed, 39 insertions, 30 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 672c17bb32d..e104e32c2ee 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -329,9 +329,12 @@ static int bdi_forker_thread(void *ptr) set_user_nice(current, 0); for (;;) { - bool fork = false; struct task_struct *task; struct backing_dev_info *bdi; + enum { + NO_ACTION, /* Nothing to do */ + FORK_THREAD, /* Fork bdi thread */ + } action = NO_ACTION; /* * Temporary measure, we want to make sure we don't see @@ -348,25 +351,31 @@ static int bdi_forker_thread(void *ptr) * a thread registered. If so, set that up. */ list_for_each_entry(bdi, &bdi_list, bdi_list) { - if (!bdi_cap_writeback_dirty(bdi)) - continue; - if (bdi->wb.task) - continue; - if (list_empty(&bdi->work_list) && - !bdi_has_dirty_io(bdi)) + bool have_dirty_io; + + if (!bdi_cap_writeback_dirty(bdi) || + bdi_cap_flush_forker(bdi)) continue; WARN(!test_bit(BDI_registered, &bdi->state), "bdi %p/%s is not registered!\n", bdi, bdi->name); - fork = true; + have_dirty_io = !list_empty(&bdi->work_list) || + wb_has_dirty_io(&bdi->wb); /* - * Set the pending bit - if someone will try to - * unregister this bdi - it'll wait on this bit. + * If the bdi has work to do, but the thread does not + * exist - create it. */ - set_bit(BDI_pending, &bdi->state); - break; + if (!bdi->wb.task && have_dirty_io) { + /* + * Set the pending bit - if someone will try to + * unregister this bdi - it'll wait on this bit. + */ + set_bit(BDI_pending, &bdi->state); + action = FORK_THREAD; + break; + } } spin_unlock_bh(&bdi_lock); @@ -374,30 +383,30 @@ static int bdi_forker_thread(void *ptr) if (!list_empty(&me->bdi->work_list)) __set_current_state(TASK_RUNNING); - if (!fork) { - unsigned long wait; + switch (action) { + case FORK_THREAD: + __set_current_state(TASK_RUNNING); + task = kthread_run(bdi_writeback_thread, &bdi->wb, "flush-%s", + dev_name(bdi->dev)); + if (IS_ERR(task)) { + /* + * If thread creation fails, force writeout of + * the bdi from the thread. + */ + bdi_flush_io(bdi); + } else + bdi->wb.task = task; + break; - wait = msecs_to_jiffies(dirty_writeback_interval * 10); - if (wait) - schedule_timeout(wait); + case NO_ACTION: + if (dirty_writeback_interval) + schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10)); else schedule(); try_to_freeze(); + /* Back to the main loop */ continue; } - - __set_current_state(TASK_RUNNING); - - task = kthread_run(bdi_writeback_thread, &bdi->wb, "flush-%s", - dev_name(bdi->dev)); - if (IS_ERR(task)) { - /* - * If thread creation fails, force writeout of the bdi - * from the thread. - */ - bdi_flush_io(bdi); - } else - bdi->wb.task = task; } return 0; |