Subject: Re: [PATCH 03/12] buffer: eliminate the need to call
 free_more_memory() in __getblk_slow()
To: Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
Cc: hannes@cmpxchg.org, jack@suse.cz, torvalds@linux-foundation.org
References: <1506543239-31470-1-git-send-email-axboe@kernel.dk>
 <1506543239-31470-4-git-send-email-axboe@kernel.dk>
From: Nikolay Borisov <nborisov@suse.com>
Message-ID: <92d672f8-1a56-3b54-082e-d760687beed8@suse.com>
Date: Thu, 28 Sep 2017 17:12:33 +0300
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On 27.09.2017 23:13, Jens Axboe wrote:
> Since the previous commit removed any case where grow_buffers()
> would return failure due to memory allocations, we can safely
> remove the case where we have to call free_more_memory() in
> this function.
> 
> Since this is also the last user of free_more_memory(), kill
> it off completely.
> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  fs/buffer.c | 23 -----------------------
>  1 file changed, 23 deletions(-)
> 
> diff --git a/fs/buffer.c b/fs/buffer.c
> index 3b60cd8456db..bff571dc7bc3 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -253,27 +253,6 @@ __find_get_block_slow(struct block_device *bdev, sector_t block)
>  }
>  
>  /*
> - * Kick the writeback threads then try to free up some ZONE_NORMAL memory.
> - */
> -static void free_more_memory(void)
> -{
> -	struct zoneref *z;
> -	int nid;
> -
> -	wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM);
> -	yield();
> -
> -	for_each_online_node(nid) {
> -
> -		z = first_zones_zonelist(node_zonelist(nid, GFP_NOFS),
> -						gfp_zone(GFP_NOFS), NULL);
> -		if (z->zone)
> -			try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0,
> -						GFP_NOFS, NULL);
> -	}
> -}
> -
> -/*
>   * I/O completion handler for block_read_full_page() - pages
>   * which come unlocked at the end of I/O.
>   */
> @@ -1086,8 +1065,6 @@ __getblk_slow(struct block_device *bdev, sector_t block,
>  		ret = grow_buffers(bdev, block, size, gfp);
>  		if (ret < 0)
>  			return NULL;
> -		if (ret == 0)
> -			free_more_memory();
>  	}
>  }
>  
>