From mboxrd@z Thu Jan 1 00:00:00 1970 From: kirill@shutemov.name (Kirill A. Shutemov) Date: Wed, 5 Nov 2014 16:58:29 +0200 Subject: Why page fault handler behaved this way? Please help! In-Reply-To: References: <771b3575.1fa3f.1495fe48476.Coremail.michaelbest002@126.com> <20141104131356.GC28274@node.dhcp.inet.fi> Message-ID: <20141105145829.GA7633@node.dhcp.inet.fi> To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org On Wed, Nov 05, 2014 at 04:18:36PM +0800, ??? wrote: > Hello, > > > Thank you very much for helping me. Before I see your reply, I enlarged > my program and I saw more page faults in code segment. Now I know there > is something called fault-around. > > > I read the Chapter 16 of the ULK which introduces file access. I started > to know a technique called read-ahead from this chapter. So what's the > difference or relationship between fault-around and read-ahead? I think > they are used in different areas (layers) but have the same idea. Am I > right? readahead reads data from backing storage to page-cache, but it doesn't map it to process' address space. fault-around maps pages which already in page cache: via readahead or not. -- Kirill A. Shutemov