From 02aaeb9b952f30b1ad6284d5d45be02030f679db Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 23 Mar 2006 03:00:04 -0800 Subject: [PATCH] [PATCH] swsusp: freeze user space processes first Allow swsusp to freeze processes successfully under heavy load by freezing userspace processes before kernel threads. [Thanks to Nigel Cunningham for suggesting the way to go.] Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/disk.c | 1 - kernel/power/process.c | 61 +++++++++++++++++++++++++++++++----------- kernel/power/user.c | 1 - 3 files changed, 46 insertions(+), 17 deletions(-) diff --git a/kernel/power/disk.c b/kernel/power/disk.c index 4bd68f482f..81d4d982f3 100644 --- a/kernel/power/disk.c +++ b/kernel/power/disk.c @@ -72,7 +72,6 @@ static int prepare_processes(void) int error; pm_prepare_console(); - sys_sync(); disable_nonboot_cpus(); if (freeze_processes()) { diff --git a/kernel/power/process.c b/kernel/power/process.c index 02a1b3a9fa..8ac7c35fad 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -12,11 +12,12 @@ #include #include #include +#include /* * Timeout for stopping processes */ -#define TIMEOUT (6 * HZ) +#define TIMEOUT (20 * HZ) static inline int freezeable(struct task_struct * p) @@ -54,38 +55,62 @@ void refrigerator(void) current->state = save; } +static inline void freeze_process(struct task_struct *p) +{ + unsigned long flags; + + if (!freezing(p)) { + freeze(p); + spin_lock_irqsave(&p->sighand->siglock, flags); + signal_wake_up(p, 0); + spin_unlock_irqrestore(&p->sighand->siglock, flags); + } +} + /* 0 = success, else # of processes that we failed to stop */ int freeze_processes(void) { - int todo; + int todo, nr_user, user_frozen; unsigned long start_time; struct task_struct *g, *p; unsigned long flags; printk( "Stopping tasks: " ); start_time = jiffies; + user_frozen = 0; do { - todo = 0; + nr_user = todo = 0; read_lock(&tasklist_lock); do_each_thread(g, p) { if (!freezeable(p)) continue; if (frozen(p)) continue; - - freeze(p); - spin_lock_irqsave(&p->sighand->siglock, flags); - signal_wake_up(p, 0); - spin_unlock_irqrestore(&p->sighand->siglock, flags); - todo++; + if (p->mm && !(p->flags & PF_BORROWED_MM)) { + /* The task is a user-space one. + * Freeze it unless there's a vfork completion + * pending + */ + if (!p->vfork_done) + freeze_process(p); + nr_user++; + } else { + /* Freeze only if the user space is frozen */ + if (user_frozen) + freeze_process(p); + todo++; + } } while_each_thread(g, p); read_unlock(&tasklist_lock); + todo += nr_user; + if (!user_frozen && !nr_user) { + sys_sync(); + start_time = jiffies; + } + user_frozen = !nr_user; yield(); /* Yield is okay here */ - if (todo && time_after(jiffies, start_time + TIMEOUT)) { - printk( "\n" ); - printk(KERN_ERR " stopping tasks timed out (%d tasks remaining)\n", todo ); + if (todo && time_after(jiffies, start_time + TIMEOUT)) break; - } } while(todo); /* This does not unfreeze processes that are already frozen @@ -94,8 +119,14 @@ int freeze_processes(void) * but it cleans up leftover PF_FREEZE requests. */ if (todo) { + printk( "\n" ); + printk(KERN_ERR " stopping tasks timed out " + "after %d seconds (%d tasks remaining):\n", + TIMEOUT / HZ, todo); read_lock(&tasklist_lock); - do_each_thread(g, p) + do_each_thread(g, p) { + if (freezeable(p) && !frozen(p)) + printk(KERN_ERR " %s\n", p->comm); if (freezing(p)) { pr_debug(" clean up: %s\n", p->comm); p->flags &= ~PF_FREEZE; @@ -103,7 +134,7 @@ int freeze_processes(void) recalc_sigpending_tsk(p); spin_unlock_irqrestore(&p->sighand->siglock, flags); } - while_each_thread(g, p); + } while_each_thread(g, p); read_unlock(&tasklist_lock); return todo; } diff --git a/kernel/power/user.c b/kernel/power/user.c index 8cabc405ca..a97406b86e 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -138,7 +138,6 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp, case SNAPSHOT_FREEZE: if (data->frozen) break; - sys_sync(); down(&pm_sem); pm_prepare_console(); disable_nonboot_cpus(); -- 2.39.5