Re: [PATCH v4 03/10] mm: apply per-task gfp constraints in fast path

[Michal Hocko]

On Thu 17-12-20 13:52:36, Pavel Tatashin wrote:
[..]
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 469016222cdb..d9546f5897f4 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -3234,11 +3234,12 @@ static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist,
>  unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
>  				gfp_t gfp_mask, nodemask_t *nodemask)
>  {
> +	gfp_t current_gfp_mask = current_gfp_context(gfp_mask);
>  	unsigned long nr_reclaimed;
>  	struct scan_control sc = {
>  		.nr_to_reclaim = SWAP_CLUSTER_MAX,
> -		.gfp_mask = current_gfp_context(gfp_mask),
> -		.reclaim_idx = gfp_zone(gfp_mask),
> +		.gfp_mask = current_gfp_mask,
> +		.reclaim_idx = gfp_zone(current_gfp_mask),
>  		.order = order,
>  		.nodemask = nodemask,
>  		.priority = DEF_PRIORITY,
> @@ -4158,17 +4159,18 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in
>  {
>  	/* Minimum pages needed in order to stay on node */
>  	const unsigned long nr_pages = 1 << order;
> +	gfp_t current_gfp_mask = current_gfp_context(gfp_mask);
>  	struct task_struct *p = current;
>  	unsigned int noreclaim_flag;
>  	struct scan_control sc = {
>  		.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
> -		.gfp_mask = current_gfp_context(gfp_mask),
> +		.gfp_mask = current_gfp_mask,
>  		.order = order,
>  		.priority = NODE_RECLAIM_PRIORITY,
>  		.may_writepage = !!(node_reclaim_mode & RECLAIM_WRITE),
>  		.may_unmap = !!(node_reclaim_mode & RECLAIM_UNMAP),
>  		.may_swap = 1,
> -		.reclaim_idx = gfp_zone(gfp_mask),
> +		.reclaim_idx = gfp_zone(current_gfp_mask),
>  	};
>  
>  	trace_mm_vmscan_node_reclaim_begin(pgdat->node_id, order,

I was hoping we had agreed these are not necessary and they shouldn't be
touched in the patch.
-- 
Michal Hocko
SUSE Labs