Date: Thu, 11 Nov 2004 20:02:06 -0500 From: David Schultz <das@FreeBSD.ORG> To: Scott Long <scottl@FreeBSD.ORG> Cc: arch@FreeBSD.ORG Subject: Re: U Area Removal Message-ID: <20041112010206.GA6657@VARK.MIT.EDU> In-Reply-To: <41940142.2040401@freebsd.org> References: <20041111030035.GA70923@VARK.MIT.EDU> <41940142.2040401@freebsd.org>
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On Thu, Nov 11, 2004, Scott Long wrote: > >I propose to remove the ability to swap the U area, allocating p_stats > >from malloced memory instead. Medium-term scheduling and swapping of > >kernel stacks would be retained. Here are the patches; !i386 testers > >wanted: > > > > http://www.freebsd.org/~das/patches/upages.diff > > > > > >[1] Most of the instances of PHOLD() and PRELE() right now never > > needed to be there or have been unnecessary ever since the PCB > > was moved out of the U area. > > > This breaks amd64 in bad ways on boot. I'll send a trace and more info > when I get a serial console hooked up. The bug jhb mentioned may be responsible for this: | +struct pstats * | +pstats_alloc(void) | +{ | + | + return (malloc(sizeof(struct plimit), M_SUBPROC, M_ZERO|M_WAITOK)); | +} | | I think you mean s/plimit/pstats/ there. On 32-bit architectures, sizeof(struct plimit) is 184 bytes and sizeof(struct pstats) is 216 bytes, so requests for either would get a 256-byte allocation and things work fine. But on 64-bit architectures, sizeof(struct plimit) is 192 bytes and sizeof(struct pstats) is 432 bytes... In any case, I've updated the patch to correct this cut-and-paste-o.
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