Date:   Fri, 3 Feb 2023 16:22:14 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Yosry Ahmed <yosryahmed@google.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        "Darrick J. Wong" <djwong@kernel.org>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        David Hildenbrand <david@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Peter Xu <peterx@redhat.com>, NeilBrown <neilb@suse.de>,
        Shakeel Butt <shakeelb@google.com>,
        Michal Hocko <mhocko@kernel.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-xfs@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC PATCH v1 1/2] mm: vmscan: refactor updating reclaimed pages
 in reclaim_state
Message-ID: <Y900tl+kRWoZac/T@casper.infradead.org>
References: <20230202233229.3895713-1-yosryahmed@google.com>
 <20230202233229.3895713-2-yosryahmed@google.com>
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On Thu, Feb 02, 2023 at 11:32:28PM +0000, Yosry Ahmed wrote:
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index 54c774af6e1c..060079f1e966 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -286,8 +286,7 @@ xfs_buf_free_pages(
>  		if (bp->b_pages[i])
>  			__free_page(bp->b_pages[i]);
>  	}
> -	if (current->reclaim_state)
> -		current->reclaim_state->reclaimed_slab += bp->b_page_count;
> +	report_freed_pages(bp->b_page_count);

XFS can be built as a module

> +++ b/mm/vmscan.c
> @@ -204,6 +204,19 @@ static void set_task_reclaim_state(struct task_struct *task,
>  	task->reclaim_state = rs;
>  }
>  
> +/*
> + * reclaim_report_freed_pages: report pages freed outside of LRU-based reclaim
> + * @pages: number of pages freed
> + *
> + * If the current process is undergoing a reclaim operation,
> + * increment the number of reclaimed pages by @pages.
> + */
> +void report_freed_pages(unsigned long pages)
> +{
> +	if (current->reclaim_state)
> +		current->reclaim_state->reclaimed += pages;
> +}
> +

report_free_pages is not EXPORT_SYMBOLed