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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Andy Whitcroft <apw@shadowen.org>
Cc: kosaki.motohiro@jp.fujitsu.com, Rik van Riel <riel@redhat.com>,
	linux-kernel@vger.kernel.org,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	linux-mm@kvack.org
Subject: Re: [patch 03/21] use an array for the LRU pagevecs
Date: Sat, 01 Mar 2008 16:02:04 +0900	[thread overview]
Message-ID: <20080301153941.528A.KOSAKI.MOTOHIRO@jp.fujitsu.com> (raw)
In-Reply-To: <20080229154056.GF28849@shadowen.org>

Hi Andy

sorry, almost mistake maked by me. 

> >  #define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
> >  
> > +static inline int is_active_lru(enum lru_list l)
> > +{
> > +	if (l == LRU_ACTIVE)
> > +		return 1;
> > +	return 0;
> 
> Can this not be:
> 
> 	return (l == LRU_ACTIVE);

yes, your code is more better.

Thanks.


> > @@ -98,6 +97,19 @@ void put_pages_list(struct list_head *pa
> >  EXPORT_SYMBOL(put_pages_list);
> >  
> >  /*
> > + * Returns the LRU list a page should be on.
> > + */
> > +enum lru_list page_lru(struct page *page)
> > +{
> > +	enum lru_list lru = LRU_BASE;
> > +
> > +	if (PageActive(page))
> > +		lru += LRU_ACTIVE;
> 
> This is introducing an assumption that LRU_BASE and LRU_INACTIVE are
> synonymous?  Would it not be better to explicitly use LRU_INACTIVE:

Yes.
this patch series assume LRU_BASE == LRU_INACTIVE.

> So either:
> 
> 	if (PageActive(page))
> 		lru = LRU_ACTIVE;
> 	else
> 		lru = LRU_INACTIVE;

if add LRU_FILE, this statement makes messy.
key point of indexed arraynize is able to arithmetic calculationed.


> Or if (as I assume) this is later going to have other mappings added in
> you could do it more like the following.  This should produce identicle
> asm, but removes any possiblity of LRU_BASE/INACTIVE slippage breaking
> things:
> 
> 	enum lru_list lru = LRU_INACTIVE;
> 
> 	if (PageActive(page))
> 		lru += (LRU_ACTIVE - LRU_INACTIVE);

I think your code is more descriptive, but not best simply.
I think LRU_BASE == LRU_INACTIVE assumption make simply code.

> > -	struct pagevec *pvec = &get_cpu_var(lru_add_active_pvecs);
> > +	if (PageActive(page)) {
> > +		ClearPageActive(page);
> > +	}
> 
> {}'s are not needed here.

agghh
thank you good catch ;)


Thank you again for your very careful reviews.


- kosaki



  reply	other threads:[~2008-03-01  7:03 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-28 19:29 [patch 00/21] VM pageout scalability improvements Rik van Riel
2008-02-28 19:29 ` [patch 01/21] move isolate_lru_page() to vmscan.c Rik van Riel
2008-02-29  2:29   ` KOSAKI Motohiro
2008-02-29  2:41     ` Rik van Riel
2008-02-29  2:47       ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 02/21] Use an indexed array for LRU variables Rik van Riel
2008-02-29 16:03   ` Andy Whitcroft
2008-03-03 18:57     ` Rik van Riel
2008-02-28 19:29 ` [patch 03/21] use an array for the LRU pagevecs Rik van Riel
2008-02-29 15:40   ` Andy Whitcroft
2008-03-01  7:02     ` KOSAKI Motohiro [this message]
2008-03-04 11:04       ` KOSAKI Motohiro
2008-03-04 20:38         ` Rik van Riel
2008-03-05  1:38           ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 04/21] free swap space on swap-in/activation Rik van Riel
2008-02-28 20:05   ` Lee Schermerhorn
2008-02-28 20:20     ` Rik van Riel
2008-02-28 19:29 ` [patch 05/21] define page_file_cache() function Rik van Riel
2008-02-29 11:53   ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 06/21] split LRU lists into anon & file sets Rik van Riel
2008-03-01 12:13   ` KOSAKI Motohiro
2008-03-01 12:46   ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 07/21] SEQ replacement for anonymous pages Rik van Riel
2008-03-03 10:50   ` barrioskmc@gmail
2008-02-28 19:29 ` [patch 08/21] (NEW) add some sanity checks to get_scan_ratio Rik van Riel
2008-03-04 10:40   ` minchan Kim
2008-02-28 19:29 ` [patch 09/21] (NEW) improve reclaim balancing Rik van Riel
2008-03-01 13:35   ` KOSAKI Motohiro
2008-03-03 19:26     ` Rik van Riel
2008-02-28 19:29 ` [patch 10/21] add newly swapped in pages to the inactive list Rik van Riel
2008-02-28 19:29 ` [patch 11/21] (NEW) more aggressively use lumpy reclaim Rik van Riel
2008-03-02 10:35   ` KOSAKI Motohiro
2008-03-02 14:23     ` Rik van Riel
2008-02-28 19:29 ` [patch 12/21] No Reclaim LRU Infrastructure Rik van Riel
     [not found]   ` <44c63dc40802282058h67f7597bvb614575f06c62e2c@mail.gmail.com>
2008-02-29 14:48     ` Lee Schermerhorn
     [not found]       ` <44c63dc40803021904n5de681datba400e08079c152d@mail.gmail.com>
2008-03-03  3:06         ` minchan Kim
2008-03-03 18:46         ` Rik van Riel
2008-03-03 23:38           ` barrioskmc@gmail
2008-03-04  1:55             ` Rik van Riel
2008-03-04 10:46   ` KOSAKI Motohiro
2008-03-04 15:05     ` Lee Schermerhorn
2008-03-04 21:21       ` Rik van Riel
2008-03-05  1:42       ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 13/21] Non-reclaimable page statistics Rik van Riel
2008-02-28 19:29 ` [patch 14/21] scan noreclaim list for reclaimable pages Rik van Riel
2008-02-28 23:41   ` Randy Dunlap
2008-02-29 14:38     ` Lee Schermerhorn
2008-02-28 19:29 ` [patch 15/21] ramfs pages are non-reclaimable Rik van Riel
2008-02-28 19:29 ` [patch 16/21] SHM_LOCKED pages are nonreclaimable Rik van Riel
2008-02-28 19:29 ` [patch 17/21] non-reclaimable mlocked pages Rik van Riel
     [not found]   ` <44c63dc40802282055q508af6ccsb0e8ac3fb5e67d24@mail.gmail.com>
2008-02-29 14:47     ` Lee Schermerhorn
2008-02-28 19:29 ` [patch 18/21] mlock vma pages under mmap_sem held for read Rik van Riel
2008-02-28 19:29 ` [patch 19/21] handle mlocked pages during map/unmap and truncate Rik van Riel
2008-02-28 19:29 ` [patch 20/21] account mlocked pages Rik van Riel
2008-02-28 19:29 ` [patch 21/21] cull non-reclaimable anon pages from the LRU at fault time Rik van Riel
2008-02-28 20:19   ` Lee Schermerhorn
2008-02-28 22:27     ` Rik van Riel
2008-02-28 19:49 ` [patch 00/21] VM pageout scalability improvements Rik van Riel
2008-02-28 20:14 ` John Stoffel
2008-02-28 20:23   ` Rik van Riel

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