On Wednesday 15 April 2009, Arve Hjønnevåg wrote:> If a suspend_blocker is active, suspend will fail anyway. Since> try_to_freeze_tasks can take up to 20 seconds to complete or fail, aborting> as soon as someone blocks suspend (e.g. from an interrupt handler) improves> the worst case wakeup latency.> > On an older kernel where task freezing could fail for processes attached> to a debugger, this fixed a problem where the device sometimes hung for> 20 seconds before the screen turned on.> > Signed-off-by: Arve Hjønnevåg <arve@xxxxxxxxxxx>> ---> kernel/power/process.c | 23 ++++++++++++++++++-----> 1 files changed, 18 insertions(+), 5 deletions(-)> > diff --git a/kernel/power/process.c b/kernel/power/process.c> index ca63401..76d7cdb 100644> --- a/kernel/power/process.c> +++ b/kernel/power/process.c> @@ -13,6 +13,7 @@> #include <linux/module.h>> #include <linux/syscalls.h>> #include <linux/freezer.h>> +#include <linux/suspend_block.h>> > /* > * Timeout for stopping processes> @@ -36,6 +37,7 @@ static int try_to_freeze_tasks(bool sig_only)> struct timeval start, end;> u64 elapsed_csecs64;> unsigned int elapsed_csecs;> + unsigned int wakeup = 0;
Make it a bool, please.
> do_gettimeofday(&start);> > @@ -62,6 +64,10 @@ static int try_to_freeze_tasks(bool sig_only)> } while_each_thread(g, p);> read_unlock(&tasklist_lock);> yield(); /* Yield is okay here */> + if (todo && suspend_is_blocked()) {> + wakeup = 1;
'true', please.
> + break;> + }> if (time_after(jiffies, end_time))> break;> } while (todo);> @@ -77,11 +83,18 @@ static int try_to_freeze_tasks(bool sig_only)> * and caller must call thaw_processes() if something fails),> * but it cleans up leftover PF_FREEZE requests.> */> - printk("\n");> - printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "> - "(%d tasks refusing to freeze):\n",> - elapsed_csecs / 100, elapsed_csecs % 100, todo);> - show_state();> + if (wakeup) {> + printk("\n");
Why is the separate printk() necessary ?
> + printk(KERN_ERR "Freezing of %s aborted\n",> + sig_only ? "user space " : "tasks ");> + } else {> + printk("\n");
Why is the separate printk() necessary ?
> + printk(KERN_ERR> + "Freezing of tasks failed after %d.%02d seconds "> + "(%d tasks refusing to freeze):\n",> + elapsed_csecs / 100, elapsed_csecs % 100, todo);> + show_state();> + }> read_lock(&tasklist_lock);> do_each_thread(g, p) {> task_lock(p);
-- Everyone knows that debugging is twice as hard as writing a programin the first place. So if you're as clever as you can be when you write it,how will you ever debug it? --- Brian Kernighan_______________________________________________linux-pm mailing listlinux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.linux-foundation.org/mailman/listinfo/linux-pm
