Date: Sat, 26 Oct 2019 19:49:38 +0200 From: Antoine Brodin <antoine@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org, Gerald Pfeifer <gerald@freebsd.org> Subject: Re: svn commit: r354095 - in head/sys: amd64/amd64 amd64/include kern Message-ID: <CAALwa8nBP13Dw2XmecdU31EuveAHSHkmfAVkTDBMgrFM%2BhSGmg@mail.gmail.com> In-Reply-To: <20191026130048.GL73312@kib.kiev.ua> References: <201910252009.x9PK9gIV092660@repo.freebsd.org> <CAALwa8n9WK8FGn%2BmB=FoNuf=%2B8JmOtpg00m=KB3Z_O4Y38PMAw@mail.gmail.com> <20191026082655.GJ73312@kib.kiev.ua> <CAALwa8kb=JRX=%2BnJsC%2BUL%2BvQMsBHxtbH6GpmNJ2f4DCP9MuESQ@mail.gmail.com> <20191026130048.GL73312@kib.kiev.ua>
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On Sat, Oct 26, 2019 at 3:01 PM Konstantin Belousov <kostikbel@gmail.com> wrote: > On Sat, Oct 26, 2019 at 02:16:19PM +0200, Antoine Brodin wrote: > > On Sat, Oct 26, 2019 at 10:27 AM Konstantin Belousov > > <kostikbel@gmail.com> wrote: > > > On Sat, Oct 26, 2019 at 08:24:09AM +0200, Antoine Brodin wrote: > > > > On Fri, Oct 25, 2019 at 10:09 PM Konstantin Belousov <kib@freebsd.org> wrote: > > > > > > > > > > Author: kib > > > > > Date: Fri Oct 25 20:09:42 2019 > > > > > New Revision: 354095 > > > > > URL: https://svnweb.freebsd.org/changeset/base/354095 > > > > > > > > > > Log: > > > > > amd64: move pcb out of kstack to struct thread. > > > > > > > > > > This saves 320 bytes of the precious stack space. > > > > > > > > > > The only negative aspect of the change I can think of is that the > > > > > struct thread increased by 320 bytes obviously, and that 320 bytes are > > > > > not swapped out anymore. I believe the freed stack space is much more > > > > > important than that. Also, current struct thread size is 1392 bytes > > > > > on amd64, so UMA will allocate two thread structures per (4KB) slab, > > > > > which leaves a space for pcb without increasing zone memory use. > > > > > > > > > > Reviewed by: alc, markj > > > > > Tested by: pho > > > > > Sponsored by: The FreeBSD Foundation > > > > > MFC after: 2 weeks > > > > > Differential revision: https://reviews.freebsd.org/D22138 > > > > > > > > Hi, > > > > > > > > It seems that this breaks at least some versions of gcc: > > > > > > > > In file included from /usr/include/sys/proc.h:75, > > > > from /usr/include/sys/user.h:51, > > > > from ./md-unwind-support.h:34, > > > > from > > > > /wrkdirs/usr/ports/lang/gcc10-devel/work/gcc-10-20191020/libgcc/unwind-dw2.c:412: > > > > /usr/include/machine/proc.h:76:13: error: field 'md_pcb' has incomplete type > > > > 76 | struct pcb md_pcb; > > > > | ^~~~~~ > > > > > > > > > > It is very strange. Are gcc 9 or 8 affected ? > > > > gcc 8 and 9 are affected too. > Then this is a completely different cause then I guessed below, and I think > I know why. All of 8/9/10 gcc ports have support for multiarch, and the > error must happen for gcc or xgcc invocation with -m32, am I right ? > > If yes, please try the patch at the end of the message instead. > > diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h > index 44e34fa5c83..8800b355c9a 100644 > --- a/sys/amd64/include/pcb.h > +++ b/sys/amd64/include/pcb.h > @@ -116,6 +116,10 @@ struct susppcb { > /* fpu context for suspend/resume */ > void *sp_fpususpend; > }; > +#else /* 32bit */ > +struct pcb { > + uint64_t pcb_dummy[40]; > +}; > #endif > > #ifdef _KERNEL Hi, It builds fine with this patch. Antoine
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