Re: Problem in Page Cache Replacement

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Nov 22, 2012 at 11:41:07PM +0800, Fengguang Wu wrote:
> On Wed, Nov 21, 2012 at 12:07:22PM +0200, Metin Döşlü wrote:
> > On Wed, Nov 21, 2012 at 12:00 PM, Jaegeuk Hanse <jaegeuk.hanse@xxxxxxxxx> wrote:
> > >
> > > On 11/21/2012 05:58 PM, metin d wrote:
> > >
> > > Hi Fengguang,
> > >
> > > I run tests and attached the results. The line below I guess shows the data-1 page caches.
> > >
> > > 0x000000080000006c       6584051    25718  __RU_lA___________________P________    referenced,uptodate,lru,active,private
> > >
> > >
> > > I thinks this is just one state of page cache pages.
> > 
> > But why these page caches are in this state as opposed to other page
> > caches. From the results I conclude that:
> > 
> > data-1 pages are in state : referenced,uptodate,lru,active,private
> 
> I wonder if it's this code that stops data-1 pages from being
> reclaimed:
> 
> shrink_page_list():
> 
>                 if (page_has_private(page)) {
>                         if (!try_to_release_page(page, sc->gfp_mask))
>                                 goto activate_locked;
> 
> What's the filesystem used?

Ah it's more likely caused by this logic:

        if (is_active_lru(lru)) {
                if (inactive_list_is_low(mz, file))
                        shrink_active_list(nr_to_scan, mz, sc, priority, file);

The active file list won't be scanned at all if it's smaller than the
active list. In this case, it's inactive=33586MB > active=25719MB. So
the data-1 pages in the active list will never be scanned and reclaimed.

> > data-2 pages are in state : referenced,uptodate,lru,mappedtodisk
> 
> Thanks,
> Fengguang

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]