linux-kernel - Re: [PATCH v2 2/2] mm/vmalloc: Remove gfpflags_allow

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Date:   Wed, 7 Jul 2021 10:51:22 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     "Uladzislau Rezki (Sony)" <urezki@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        LKML <linux-kernel@...r.kernel.org>,
        Mel Gorman <mgorman@...e.de>,
        Christoph Hellwig <hch@...radead.org>,
        Matthew Wilcox <willy@...radead.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Hillf Danton <hdanton@...a.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH v2 2/2] mm/vmalloc: Remove gfpflags_allow_blocking() check

On Mon 05-07-21 19:05:37, Uladzislau Rezki (Sony) wrote:
> Get rid of gfpflags_allow_blocking() check from the vmalloc() path
> as it is supposed to be sleepable anyway. Thus remove it from the
> alloc_vmap_area() as well as from the vm_area_alloc_pages().
> 
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>

Acked-by: Michal Hocko <mhocko@...e.com>

> ---
>  mm/vmalloc.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 5297958ac7c5..93a9cbdba905 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1479,6 +1479,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
>  				int node, gfp_t gfp_mask)
>  {
>  	struct vmap_area *va;
> +	unsigned long freed;
>  	unsigned long addr;
>  	int purged = 0;
>  	int ret;
> @@ -1542,13 +1543,12 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
>  		goto retry;
>  	}
>  
> -	if (gfpflags_allow_blocking(gfp_mask)) {
> -		unsigned long freed = 0;
> -		blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
> -		if (freed > 0) {
> -			purged = 0;
> -			goto retry;
> -		}
> +	freed = 0;
> +	blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
> +
> +	if (freed > 0) {
> +		purged = 0;
> +		goto retry;
>  	}
>  
>  	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
> @@ -2834,9 +2834,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
>  		for (i = 0; i < (1U << order); i++)
>  			pages[nr_allocated + i] = page + i;
>  
> -		if (gfpflags_allow_blocking(gfp))
> -			cond_resched();
> -
> +		cond_resched();
>  		nr_allocated += 1U << order;
>  	}
>  
> -- 
> 2.20.1

-- 
Michal Hocko
SUSE Labs