Date: Thu, 9 Jun 2005 06:31:13 -0700 From: John Baldwin <jhb@FreeBSD.org> To: Peter Jeremy <PeterJeremy@optushome.com.au> Cc: hackers@freebsd.org, Hans Petter Selasky <hselasky@c2i.net> Subject: Re: problems with new the "contigmalloc" routine Message-ID: <1bc2efb62d58b3be72efe326781aee70@FreeBSD.org> In-Reply-To: <20050520224928.GI2129@cirb503493.alcatel.com.au> References: <200505201340.36176.hselasky@c2i.net> <428E12B0.9020208@samsco.org> <20050520173236.GG1201@green.homeunix.org> <200505202151.35831.hselasky@c2i.net> <20050520224928.GI2129@cirb503493.alcatel.com.au>
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On May 20, 2005, at 3:49 PM, Peter Jeremy wrote: > On Fri, 2005-May-20 21:51:34 +0200, Hans Petter Selasky wrote: >> Can anyone explain why "uiomove()" has to sleep, and why there is no >> non-blocking "uiomove()"? > > As far as I can see, uiomove() only sleeps if it is asked to do a > kernel<->userland move that takes more than twice a scheduler quantum. > As long as you don't uiomove() ridiculous amounts of data, it should > never sleep. It can also sleep if it is reading from or writing to user memory if any of that memory needs to be faulted in. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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