Date: Tue, 25 Dec 2001 12:04:45 +0200 From: "Barak Enat" <barak_enat@yahoo.com> To: <freebsd-hackers@freebsd.org> Subject: Virtual memory and paging questions Message-ID: <038f01c18d2b$9a7a9700$e36596d4@cwnt.com>
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[-- Attachment #1 --] Hi all, Note: Please reply to this mail as well because I'm not subscribed to this mailing list. I have two questions regarding FreeBSD virtual memory and paging/swapping system: 1. When a page fault occurs does the entire system stalls, or only the process that requested the page suspends till the asynchronous completion of the page read? 2. If I create a memory disk (md) and later use it for swapping (sounds awkward - but still this is what I need...), when a page fault occurs does a physical memcopy happen from the md page to the main memory page, or is there a trick in the vm page mapping to actually use the same physical page from the md? If such a trick exist, where is it in the code (because I want to turn it off - I need the simple memcopy behaviour.) Thanks in adavnce, Barak [-- Attachment #2 --] <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META content="text/html; charset=windows-1255" http-equiv=Content-Type> <META content="MSHTML 5.00.3315.2870" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Hi all,</FONT></DIV> <DIV> </DIV> <DIV><FONT face="Arial (Hebrew)" size=2>Note: Please reply to this mail as well because I'm not subscribed to this mailing list.</FONT></DIV> <DIV> </DIV> <DIV><FONT face="Arial (Hebrew)" size=2>I have two questions regarding FreeBSD virtual memory and paging/swapping system:</FONT></DIV> <DIV><FONT face="Arial (Hebrew)" size=2></FONT> </DIV> <DIV><FONT face="Arial (Hebrew)" size=2>1. When a page fault occurs does the entire system stalls, or only the process that requested the page suspends till the asynchronous completion of the page read?</FONT></DIV> <DIV> </DIV> <DIV><FONT face="Arial (Hebrew)" size=2>2. If I create a memory disk (md) and later use it for swapping (sounds awkward - but still this is what I need...), when a page fault occurs does a physical memcopy happen from the md page to the main memory page, or is there a trick in the vm page mapping to actually use the same physical page from the md? If such a trick exist, where is it in the code (because I want to turn it off - I need the simple memcopy behaviour.)</FONT></DIV> <DIV> </DIV> <DIV><FONT face="Arial (Hebrew)" size=2>Thanks in adavnce,</FONT></DIV> <DIV><FONT face="Arial (Hebrew)" size=2>Barak</FONT></DIV> <DIV> </DIV></BODY></HTML>
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