From: Andrew Morton pdflush is carefully designed to ensure that all wakeups have some corresponding work to do - if a woken-up pdflush thread discovers that it hasn't been given any work to do then this is considered an error. That all broke when swsusp came along - because a timer-delivered wakeup to a frozen pdflush thread will just get lost. This causes the pdflush thread to get lost as well: the writeback timer is supposed to be re-armed by pdflush in process context, but pdflush doesn't execute the callout which does this. Fix that up by ignoring the return value from try_to_freeze(): jsut proceed, see if we have any work pending and only go back to sleep if that is not the case. Signed-off-by: Andrew Morton --- mm/pdflush.c | 15 +++++++-------- 1 files changed, 7 insertions(+), 8 deletions(-) diff -puN mm/pdflush.c~pdflush-handle-resume-wakeups mm/pdflush.c --- devel/mm/pdflush.c~pdflush-handle-resume-wakeups 2006-05-22 13:40:25.000000000 -0700 +++ devel-akpm/mm/pdflush.c 2006-05-22 14:02:23.000000000 -0700 @@ -104,21 +104,20 @@ static int __pdflush(struct pdflush_work list_move(&my_work->list, &pdflush_list); my_work->when_i_went_to_sleep = jiffies; spin_unlock_irq(&pdflush_lock); - schedule(); - if (try_to_freeze()) { - spin_lock_irq(&pdflush_lock); - continue; - } - + try_to_freeze(); spin_lock_irq(&pdflush_lock); if (!list_empty(&my_work->list)) { - printk("pdflush: bogus wakeup!\n"); + /* + * Someone woke us up, but without removing our control + * structure from the global list. swsusp will do this + * in try_to_freeze()->refrigerator(). Handle it. + */ my_work->fn = NULL; continue; } if (my_work->fn == NULL) { - printk("pdflush: NULL work function\n"); + printk("pdflush: bogus wakeup\n"); continue; } spin_unlock_irq(&pdflush_lock); _