Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: question related page frame reclaim on embedded system | Date | Thu, 4 Dec 2008 19:16:42 +0900 (JST) |
| |
> Hi,Kosaki > > 1. what happens if used IPC share memory ? > As i knew IPC share memory use anonymous mapping ,but not sure my understand is correctly .
Yes. if you don't free IPC share memory, it remain on the system until reboot.
> > Thanks advanced . > Best Regards. > Peter > > > --- On Wed, 12/3/08, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote: > > > From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > > Subject: Re: question related page frame reclaim on embedded system > > To: mengsanshui@yahoo.com.cn > > Cc: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org > > Date: Wednesday, December 3, 2008, 9:48 AM > > > > > > Hi,Kosaki > > > > > > Thank you very much . > > > I have another question about share memory . Assume a > > process create a share memory , > > > seems the page that the process used can not be > > discard or swap out > > > > No. Linux can swap out COW shared memory too. see swap > > cache related code. > > Also, Linux can discard non-dirty and file mapped shared > > page. > > > > but, yes. > > Linux can't discart dirty or anonymous mapped page. > > > > > > > when they are no longer used by any process or no swap > > space . > > > > > > 1.whether the maped page of the share memory is > > persistent in system until > > > system restart ? if not how page frame reclaiming > > process it ? > > > > No. > > Linux manage page reference count. > > forrk increment it. exit decrement it. > > So, when process exiting, Linux can discard non used page > > immediately. > > > > IOW, reclaim provide "page discard/swap although page > > is still used" mechanism. > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
| |