linux-kernel - Re: [PATCH V2 2/7] mm: move MADV_FREE pages into LRU_INACTIVE

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Date:   Sat, 04 Feb 2017 14:38:07 +0800
From:   "Hillf Danton" <hillf.zj@...baba-inc.com>
To:     "'Shaohua Li'" <shli@...com>, <linux-kernel@...r.kernel.org>,
        <linux-mm@...ck.org>
Cc:     <Kernel-team@...com>, <danielmicay@...il.com>, <mhocko@...e.com>,
        <minchan@...nel.org>, <hughd@...gle.com>, <hannes@...xchg.org>,
        <riel@...hat.com>, <mgorman@...hsingularity.net>,
        <akpm@...ux-foundation.org>
Subject: Re: [PATCH V2 2/7] mm: move MADV_FREE pages into LRU_INACTIVE_FILE list

On February 04, 2017 7:33 AM Shaohua Li wrote: 
> @@ -1404,6 +1401,8 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  		set_pmd_at(mm, addr, pmd, orig_pmd);
>  		tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
>  	}
> +
> +	mark_page_lazyfree(page);
>  	ret = true;
>  out:
>  	spin_unlock(ptl);

<snipped>

> -void deactivate_page(struct page *page)
> -{
> -	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
> -		struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
> +void mark_page_lazyfree(struct page *page)
> + {
> +	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
> +	    !PageUnevictable(page)) {
> +		struct pagevec *pvec = &get_cpu_var(lru_lazyfree_pvecs);
> 
>  		get_page(page);
>  		if (!pagevec_add(pvec, page) || PageCompound(page))
> -			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
> -		put_cpu_var(lru_deactivate_pvecs);
> +			pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
> +		put_cpu_var(lru_lazyfree_pvecs);
>  	}
>  }

You are not adding it but would you please try to fix or avoid flipping
preempt count with page table lock hold?

thanks
Hillf