From 3e1d1d28d99dabe63c64f7f40f1ca1d646de1f73 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Fri, 24 Jun 2005 23:13:50 -0700 Subject: [PATCH] Cleanup patch for process freezing 1. Establish a simple API for process freezing defined in linux/include/sched.h: frozen(process) Check for frozen process freezing(process) Check if a process is being frozen freeze(process) Tell a process to freeze (go to refrigerator) thaw_process(process) Restart process frozen_process(process) Process is frozen now 2. Remove all references to PF_FREEZE and PF_FROZEN from all kernel sources except sched.h 3. Fix numerous locations where try_to_freeze is manually done by a driver 4. Remove the argument that is no longer necessary from two function calls. 5. Some whitespace cleanup 6. Clear potential race in refrigerator (provides an open window of PF_FREEZE cleared before setting PF_FROZEN, recalc_sigpending does not check PF_FROZEN). This patch does not address the problem of freeze_processes() violating the rule that a task may only modify its own flags by setting PF_FREEZE. This is not clean in an SMP environment. freeze(process) is therefore not SMP safe! Signed-off-by: Christoph Lameter Signed-off-by: Linus Torvalds --- mm/pdflush.c | 2 +- mm/vmscan.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'mm') diff --git a/mm/pdflush.c b/mm/pdflush.c index 38ce279cc8cd..d6781951267e 100644 --- a/mm/pdflush.c +++ b/mm/pdflush.c @@ -105,7 +105,7 @@ static int __pdflush(struct pdflush_work *my_work) spin_unlock_irq(&pdflush_lock); schedule(); - if (try_to_freeze(PF_FREEZE)) { + if (try_to_freeze()) { spin_lock_irq(&pdflush_lock); continue; } diff --git a/mm/vmscan.c b/mm/vmscan.c index 4b8e62a19370..1fa312a8db77 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1216,8 +1216,8 @@ static int kswapd(void *p) order = 0; for ( ; ; ) { unsigned long new_order; - if (current->flags & PF_FREEZE) - refrigerator(PF_FREEZE); + + try_to_freeze(); prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); new_order = pgdat->kswapd_max_order; -- cgit v1.2.2