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Date:      Wed, 29 May 2002 10:45:33 +0800
From:      "kai ouyang" <oykai@msn.com>
To:        "Julian Elischer" <julian@elischer.org>, <current@FreeBSD.org>
Subject:   Re:why change: from proc to thread?
Message-ID:  <OE79Dt82hZPuNoqRfH300007666@hotmail.com>

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Another problem:
  There are not the structure 'bio' in FreeBSD 4.x, but exist in 5.0. =20
If I want to transfer some pseudo-device code from 4.x to 5.0, =20
what rules about old 'buf' structure to the 'bio' structure?
what relation of the 'bio' and 'buf' in FreeBSD5.0?
Thank you!
Best Regards
  Ouyang kai


On Mon, 27 May 2002, kai ouyang wrote:

> Hi,everybody
>   I found many v_operations, such as VOP_UNLOCK, VOP_OPEN....., there
> all have a parameter(struct proc) in FreeBSD4.x, but, there all be
> changed to thread in FreeBSD5.0. why? And what relation of the proc
> and thread ?
>   Thank you!
>

FreeBSD is plannig on supporting threads at a kernel level.
To do this, the basic scheduling element becomes the thread instead of th=
e
process. For this reason, for example, locks must be held by threads
instead of processes, and contexts are owned by threads instead of
processes. This means that most functions will need a thread pointer
instead of a process pointer. The "process" becomes basically an
accounting abstraction and the holder of resources, where most of the
kernel is more interested in the thread.

Each process has at least one thread, possibly many. Each thread is
associated with exactly one process.



julian=B4=D3=CD=F8=D5=BE=B5=C3=B5=BD=B8=FC=B6=E0=D0=C5=CF=A2=A1=A3MSN Exp=
lorer =C3=E2=B7=D1=CF=C2=D4=D8:http://explorer.msn.com/lccn

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<HTML><BODY STYLE=3D"font:10pt verdana; border:none;"><DIV>Another proble=
m:</DIV> <DIV>&nbsp; There are not the structure 'bio' in FreeBSD 4.x, bu=
t exist in 5.0. </DIV> <DIV>If I want to transfer some pseudo-device code=
 from 4.x to 5.0, </DIV> <DIV>what rules about old 'buf' structure to the=
 'bio' structure?</DIV> <DIV>what relation of the 'bio' and 'buf' in Free=
BSD5.0?</DIV> <DIV>Thank you!</DIV> <DIV>Best Regards</DIV> <DIV>&nbsp; O=
uyang kai</DIV> <DIV>&nbsp;</DIV> <BLOCKQUOTE style=3D"PADDING-RIGHT: 0px=
; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MA=
RGIN-RIGHT: 0px"><BR>On Mon, 27 May 2002, kai ouyang wrote:<BR><BR>&gt; H=
i,everybody<BR>&gt;&nbsp;&nbsp; I found many v_operations, such as VOP_UN=
LOCK, VOP_OPEN....., there<BR>&gt; all have a parameter(struct proc) in F=
reeBSD4.x, but, there all be<BR>&gt; changed to thread in FreeBSD5.0. why=
? And what relation of the proc<BR>&gt; and thread ?<BR>&gt;&nbsp;&nbsp; =
Thank you!<BR>&gt;<BR><BR>FreeBSD is plannig on supporting threads at a k=
ernel level.<BR>To do this, the basic scheduling element becomes the thre=
ad instead of the<BR>process. For this reason, for example, locks must be=
 held by threads<BR>instead of processes, and contexts are owned by threa=
ds instead of<BR>processes. This means that most functions will need a th=
read pointer<BR>instead of a process pointer. The "process" becomes basic=
ally an<BR>accounting abstraction and the holder of resources, where most=
 of the<BR>kernel is more interested in the thread.<BR><BR>Each process h=
as at least one thread, possibly many. Each thread is<BR>associated with =
exactly one process.<BR><BR><BR><BR>julian<BR><BR><BR></BLOCKQUOTE></BODY=
></HTML><br clear=3Dall><hr>=B4=D3=CD=F8=D5=BE=B5=C3=B5=BD=B8=FC=B6=E0=D0=
=C5=CF=A2=A1=A3MSN Explorer =C3=E2=B7=D1=CF=C2=D4=D8=A3=BA<a href=3D'http=
://explorer.msn.com/lccn'>http://explorer.msn.com/lccn</a><br></p>;

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