__lock_page calls run_task_queue(&tq_disk) unecessarily?

From: Marcelo Tosatti (marcelo@conectiva.com.br)
Date: Mon Feb 19 2001 - 18:02:55 EST

Hi Linus,

Take a look at __lock_page:

static void __lock_page(struct page *page)
        struct task_struct *tsk = current;
        DECLARE_WAITQUEUE(wait, tsk);

        add_wait_queue_exclusive(&page->wait, &wait);
        for (;;) {
                set_task_state(tsk, TASK_UNINTERRUPTIBLE);
                if (PageLocked(page)) {
                if (!TryLockPage(page))
        tsk->state = TASK_RUNNING;
        remove_wait_queue(&page->wait, &wait);

Af a process sleeps in __lock_page, sync_page() will be called even if the
page is already unlocked. (block_sync_page(), the sync_page routine for
generic block based filesystem calls run_task_queue(&tq_disk)).

I don't see any problem if we remove the run_task_queue(&tq_disk) and put
sync_page(page) there instead, removing the other sync_page(page) at the
beginning of the loop.


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This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:21 EST