Re: page faults

[Wang Yong <wung_y@263.net>]

the page fault is an interrupt and do_page_fault is the handler, so no other
page fault
will be received in do_page_fault. this is true for linux because it's not
preemptive.
if the page fault is caused by a write to a shared page, do_wp_page will be
called
to copy this page to a new page(copy on write).

"Benjamin C.R. LaHaise" wrote:

> On Thu, 21 Oct 1999, James Simmons wrote:
>
> > Quick question. If two processes are sharing the same memory but no page
> > fault has happened. THen process A causes a page fault. If process B tries
> > to access the page that process A already page fault will process B cause
> > another page fault. Or do page faults only happen once no matter how many
> > process access it.
>
> Only the first time the page is accessed is there a fault to put the entry
> into the page table, regardless of the processes sharing the page.  The
> only time entries are removed from a process' page tables is on fork
> (ie marking private pages read only so COW works), unmap or vmscan's page
> reclaims.
>
>                 -ben
>
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