Re: [patch v2 2/3] mm, oom: organize oom context into struct

From: Michal Hocko
Date: Thu Jul 02 2015 - 02:02:25 EST


On Wed 01-07-15 14:37:14, David Rientjes wrote:
> The force_kill member of struct oom_control isn't needed if an order of
> -1 is used instead. This is the same as order == -1 in
> struct compact_control which requires full memory compaction.
>
> This patch introduces no functional change.

But it obscures the code and I really dislike this change as pointed out
previously.

> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
> ---
> v2: fix changelog typo per Sergey
>
> drivers/tty/sysrq.c | 3 +--
> include/linux/oom.h | 1 -
> mm/memcontrol.c | 1 -
> mm/oom_kill.c | 5 ++---
> mm/page_alloc.c | 1 -
> 5 files changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
> --- a/drivers/tty/sysrq.c
> +++ b/drivers/tty/sysrq.c
> @@ -358,8 +358,7 @@ static void moom_callback(struct work_struct *ignored)
> .zonelist = node_zonelist(first_memory_node, gfp_mask),
> .nodemask = NULL,
> .gfp_mask = gfp_mask,
> - .order = 0,
> - .force_kill = true,
> + .order = -1,
> };
>
> mutex_lock(&oom_lock);
> diff --git a/include/linux/oom.h b/include/linux/oom.h
> --- a/include/linux/oom.h
> +++ b/include/linux/oom.h
> @@ -17,7 +17,6 @@ struct oom_control {
> nodemask_t *nodemask;
> gfp_t gfp_mask;
> int order;
> - bool force_kill;
> };
>
> /*
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1550,7 +1550,6 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
> .nodemask = NULL,
> .gfp_mask = gfp_mask,
> .order = order,
> - .force_kill = false,
> };
> struct mem_cgroup *iter;
> unsigned long chosen_points = 0;
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -265,7 +265,7 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
> * Don't allow any other task to have access to the reserves.
> */
> if (test_tsk_thread_flag(task, TIF_MEMDIE)) {
> - if (!oc->force_kill)
> + if (oc->order != -1)
> return OOM_SCAN_ABORT;
> }
> if (!task->mm)
> @@ -278,7 +278,7 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
> if (oom_task_origin(task))
> return OOM_SCAN_SELECT;
>
> - if (task_will_free_mem(task) && !oc->force_kill)
> + if (task_will_free_mem(task) && oc->order != -1)
> return OOM_SCAN_ABORT;
>
> return OOM_SCAN_OK;
> @@ -718,7 +718,6 @@ void pagefault_out_of_memory(void)
> .nodemask = NULL,
> .gfp_mask = 0,
> .order = 0,
> - .force_kill = false,
> };
>
> if (mem_cgroup_oom_synchronize(true))
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2685,7 +2685,6 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
> .nodemask = ac->nodemask,
> .gfp_mask = gfp_mask,
> .order = order,
> - .force_kill = false,
> };
> struct page *page;
>

--
Michal Hocko
SUSE Labs
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