linux-kernel - Re: [PATCH v2 1/3] deactivate invalidated pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 29 Nov 2010 09:33:38 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	Minchan Kim <minchan.kim@...il.com>
Cc:	kosaki.motohiro@...fujitsu.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-mm <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Ben Gamari <bgamari.foss@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Wu Fengguang <fengguang.wu@...el.com>,
	Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Nick Piggin <npiggin@...nel.dk>, Mel Gorman <mel@....ul.ie>
Subject: Re: [PATCH v2 1/3] deactivate invalidated pages

> ---
>  mm/swap.c |   84 +++++++++++++++++++++++++++++++++++++++++++++---------------
>  1 files changed, 63 insertions(+), 21 deletions(-)
> 
> diff --git a/mm/swap.c b/mm/swap.c
> index 31f5ec4..345eca1 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -268,10 +268,65 @@ void add_page_to_unevictable_list(struct page *page)
>  	spin_unlock_irq(&zone->lru_lock);
>  }
>  
> -static void __pagevec_lru_deactive(struct pagevec *pvec)
> +/*
> + * This function is used by invalidate_mapping_pages.
> + * If the page can't be invalidated, this function moves the page
> + * into inative list's head or tail to reclaim ASAP and evict
> + * working set page.
> + *
> + * PG_reclaim means when the page's writeback completes, the page
> + * will move into tail of inactive for reclaiming ASAP.
> + *
> + * 1. active, mapped page -> inactive, head
> + * 2. active, dirty/writeback page -> inactive, head, PG_reclaim
> + * 3. inactive, mapped page -> none
> + * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
> + * 5. others -> none
> + *
> + * In 4, why it moves inactive's head, the VM expects the page would
> + * be writeout by flusher. The flusher's writeout is much effective than
> + * reclaimer's random writeout.
> + */
> +static void __lru_deactivate(struct page *page, struct zone *zone)
>  {
> -	int i, lru, file;
> +	int lru, file;
> +	int active = 0;
> +
> +	if (!PageLRU(page))
> +		return;
> +
> +	if (PageActive(page))
> +		active = 1;
> +	/* Some processes are using the page */
> +	if (page_mapped(page) && !active)
> +		return;
> +
> +	else if (PageWriteback(page)) {
> +		SetPageReclaim(page);
> +		/* Check race with end_page_writeback */
> +		if (!PageWriteback(page))
> +			ClearPageReclaim(page);
> +	} else if (PageDirty(page))
> +		SetPageReclaim(page);
> +
> +	file = page_is_file_cache(page);
> +	lru = page_lru_base_type(page);
> +	del_page_from_lru_list(zone, page, lru + active);
> +	ClearPageActive(page);
> +	ClearPageReferenced(page);
> +	add_page_to_lru_list(zone, page, lru);
> +	if (active)
> +		__count_vm_event(PGDEACTIVATE);
> +
> +	update_page_reclaim_stat(zone, page, file, 0);
> +}

I don't like this change because fadvise(DONT_NEED) is rarely used
function and this PG_reclaim trick doesn't improve so much. In the
other hand, It increase VM state mess.

However, I haven't found any fault and unworked reason in this patch.


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/