Date: Mon, 1 Feb 1999 11:06:48 +0100 From: Ladavac Marino <mladavac@metropolitan.at> To: "'John Saunders'" <john.saunders@nlc.net.au>, freebsd-current@FreeBSD.ORG Cc: Dan Swartzendruber <dswartz@druber.com> Subject: RE: btokup().. patch to STYLE(9) (fwd) Message-ID: <97A8CA5BF490D211A94F0000F6C2E55D09752A@s-lmh-wi-900.corpnet.at>
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> -----Original Message----- > From: John Saunders [SMTP:john.saunders@nlc.net.au] > Sent: Monday, February 01, 1999 10:53 AM > To: freebsd-current@FreeBSD.ORG > Cc: Dan Swartzendruber > Subject: Re: btokup().. patch to STYLE(9) (fwd) > > In nlc.lists.freebsd-current you wrote: > > At 12:09 PM 2/1/99 +1100, Gregory Bond wrote: > >>> "You are not supposed to understand this." > > "You are not expected to understand this." > > > It's inside the swtch() function call. Just having a quick look now. > > Inside expand(), where core is allocated for a process, if no core is > available the process is swapped out with a call to xswap(), then > switched out with a call to swtch(). When core becomes available and > the process image is read in from swap, the process will be selected > by swtch() to become runnable. However with the current context, > swtch() > would return and the tail end of the expand() function would execute. > So inside expand() a call is made to save the stack state so that when > swtch() restores this state, the return skips over the expand() > function > entirely. > [ML] I don't understand that. But, then again, I am not supposed to :) P.S I did understand it, but it was too good an opportunitiy to miss. /Marino To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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