Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag

David Rientjes
2009-05-05T00:37:34Z

On Tue, 5 May 2009, Rafael J. Wysocki wrote:

> Index: linux-2.6/kernel/power/process.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/process.c
> +++ linux-2.6/kernel/power/process.c
> @@ -19,6 +19,8 @@
> */
> #define TIMEOUT (20 * HZ)
>
> +static bool tasks_frozen;
> +
> static inline int freezeable(struct task_struct * p)
> {
> if ((p == current) ||
> @@ -120,6 +122,10 @@ int freeze_processes(void)
> Exit:
> BUG_ON(in_atomic());
> printk("\n");
> +
> + if (!error)
> + tasks_frozen = true;
> +
> return error;
> }
>
> @@ -145,6 +151,8 @@ static void thaw_tasks(bool nosig_only)
>
> void thaw_processes(void)
> {
> + tasks_frozen = false;
> +
> printk("Restarting tasks ... ");
> thaw_tasks(true);
> thaw_tasks(false);
> @@ -152,3 +160,7 @@ void thaw_processes(void)
> printk("done.\n");
> }
>
> +bool processes_are_frozen(void)
> +{
> + return tasks_frozen;
> +}
> Index: linux-2.6/include/linux/freezer.h
> ===================================================================
> --- linux-2.6.orig/include/linux/freezer.h
> +++ linux-2.6/include/linux/freezer.h
> @@ -50,6 +50,7 @@ extern int thaw_process(struct task_stru
> extern void refrigerator(void);
> extern int freeze_processes(void);
> extern void thaw_processes(void);
> +extern bool processes_are_frozen(void);
>
> static inline int try_to_freeze(void)
> {
> @@ -170,6 +171,7 @@ static inline int thaw_process(struct ta
> static inline void refrigerator(void) {}
> static inline int freeze_processes(void) { BUG(); return 0; }
> static inline void thaw_processes(void) {}
> +static inline bool processes_are_frozen(void) { return false; }
>
> static inline int try_to_freeze(void) { return 0; }
>
> Index: linux-2.6/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -46,6 +46,7 @@
> #include <linux/page-isolation.h>
> #include <linux/page_cgroup.h>
> #include <linux/debugobjects.h>
> +#include <linux/freezer.h>
>
> #include <asm/tlbflush.h>
> #include <asm/div64.h>
> @@ -1599,7 +1600,8 @@ nofail_alloc:
> zonelist, high_zoneidx, alloc_flags);
> if (page)
> goto got_pg;
> - } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
> + } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)
> + && !processes_are_frozen()) {
> if (!try_set_zone_oom(zonelist, gfp_mask)) {
> schedule_timeout_uninterruptible(1);
> goto restart;

Cool, that looks like the semantics of __GFP_NO_OOM_KILL without requiring
a new gfp flag. Thanks.