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Date:   Wed, 4 Mar 2020 11:02:48 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Alex Shi <alex.shi@linux.alibaba.com>
Cc:     cgroups@vger.kernel.org, akpm@linux-foundation.org,
        mgorman@techsingularity.net, tj@kernel.org, hughd@google.com,
        khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com,
        yang.shi@linux.alibaba.com, willy@infradead.org,
        hannes@cmpxchg.org, lkp@intel.com,
        Andrea Arcangeli <aarcange@redhat.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 06/20] mm/thp: narrow lru locking
Message-ID: <20200304080248.wuj3vqlz46ehhptg@box>
References: <1583146830-169516-1-git-send-email-alex.shi@linux.alibaba.com>
 <1583146830-169516-7-git-send-email-alex.shi@linux.alibaba.com>
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On Mon, Mar 02, 2020 at 07:00:16PM +0800, Alex Shi wrote:
> @@ -2564,6 +2565,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  		xa_lock(&swap_cache->i_pages);
>  	}
>  
> +	/* Lru list would be changed, don't care head's LRU bit. */
> +	spin_lock_irqsave(&pgdat->lru_lock, flags);
> +
>  	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
>  		__split_huge_page_tail(head, i, lruvec, list);
>  		/* Some pages can be beyond i_size: drop them from page cache */

You change locking order WRT i_pages lock. Is it safe?

-- 
 Kirill A. Shutemov