svn commit: r224217 - in head/sys: amd64/include ia64/include mips/conf sys

[John Baldwin]

On Wednesday, July 27, 2011 2:24:21 am Sergey Kandaurov wrote:
> On 21 July 2011 17:20, John Baldwin <jhb at freebsd.org> wrote:
> > On Thursday, July 21, 2011 8:37:26 am Sergey Kandaurov wrote:
> >> On 21 July 2011 14:14, Attilio Rao <attilio at freebsd.org> wrote:
> >> > 2011/7/20 Pan Tsu <inyaoo at gmail.com>:
> >> >> Attilio Rao <attilio at FreeBSD.org> writes:
> >> >>
> >> >>> Author: attilio
> >> >>> Date: Tue Jul 19 13:00:30 2011
> >> >>> New Revision: 224217
> >> >>> URL: http://svn.freebsd.org/changeset/base/224217
> >> >>>
> >> >>> Log:
> >> >>>   Bump MAXCPU for amd64, ia64 and XLP mips appropriately.
> >> >>>   From now on, default values for FreeBSD will be 64 maxiumum supported
> >> >>>   CPUs on amd64 and ia64 and 128 for XLP. All the other architectures
> >> >>>   seem already capped appropriately (with the exception of sparc64 which
> >> >>>   needs further support on jalapeno flavour).
> >> >>>
> >> >>>   Bump __FreeBSD_version in order to reflect KBI/KPI brekage introduced
> >> >>>   during the infrastructure cleanup for supporting MAXCPU > 32. This
> >> >>>   covers cpumask_t retiral too.
> >> >>>
> >> >>>   The switch is considered completed at the present time, so for
> > whatever
> >> >>>   bug you may experience that is reconducible to that area, please
> > report
> >> >>>   immediately.
> >> >>>
> >> >>>   Requested by:       marcel, jchandra
> >> >>>   Tested by:  pluknet, sbruno
> >> >>>   Approved by:        re (kib)
> >> >>>
> >> >>> Modified:
> >> >>>   head/sys/amd64/include/param.h
> >> >>>   head/sys/ia64/include/param.h
> >> >>>   head/sys/mips/conf/XLP
> >> >>>   head/sys/mips/conf/XLP64
> >> >>>   head/sys/mips/conf/XLPN32
> >> >>>   head/sys/sys/param.h
> >> >>>
> >> >>> Modified: head/sys/amd64/include/param.h
> >> >>>
> > ==============================================================================
> >> >>> --- head/sys/amd64/include/param.h    Tue Jul 19 12:41:57 2011
> >  (r224216)
> >> >>> +++ head/sys/amd64/include/param.h    Tue Jul 19 13:00:30 2011
> >  (r224217)
> >> >>> @@ -65,7 +65,7 @@
> >> >>>
> >> >>>  #if defined(SMP) || defined(KLD_MODULE)
> >> >>>  #ifndef MAXCPU
> >> >>> -#define MAXCPU               32
> >> >>> +#define MAXCPU               64
> >> >>>  #endif
> >> >>>  #else
> >> >>>  #define MAXCPU               1
> >> >>
> >> >> Do you plan to bump MEMSTAT_MAXCPU, too?
> >> >>
> >> >>  $ vmstat -z
> >> >>  vmstat: memstat_sysctl_uma: Too many CPUs
> >> >>  $ vmstat -m
> >> >>  vmstat: memstat_sysctl_malloc: Too many CPUs
> >> >>
> >> >>  $ sysctl kern. | grep smp.\*cpus
> >> >>  kern.smp.maxcpus: 64
> >> >>  kern.smp.cpus: 2
> >> >>
> >> >
> >> > Jeeeez, we seriously need to fix this getting rid of the static values.
> >> >
> >> > Anyway, can you try the following patch?:
> >> > http://www.freebsd.org/~attilio/memstat_maxcpu.diff
> >> >
> >> > It is going to add some memory overhead for i386 case.
> >> >
> >>
> >> Something like this should work (vmstat -z, vmstat -m both work).
> >> It gets rid of MEMSTAT_MAXCPU at the expense of malloc() at runtime.
> >> http://plukky.net/~pluknet/patches/libmemstat_nomaxcpu.diff
> >>
> >> Probably it should work with maxid, instead of maxcpu to save some memory.
> >> Though, using maxcpu is more safe.
> >
> > Actually, I would prefer that it use mp_maxid as that is the general variable
> > things should use.  mp_maxcpus is a concession for the few places that may
> > need to know the MAXCPUS value (e.g. if using libkvm to access a structure in
> > a crashdump or live kernel that has a member array with MAXCPU elements).
> > Code that just wants to allocate memory to hold per-CPU data should use
> > mp_maxid whenever possible.
> >
> 
> Hi,
> 
> I changed the patch to use mp_maxid wherever possible.
> http://plukky.net/~pluknet/patches/libmemstat_nomaxcpu.2.diff
> 
> To summarize:
> 
> 1) malloc stats
> kern.malloc_stats uses internally MAXCPU, and we have to query MAXCPU
> from kernel, too. See kern/kern_malloc.c:sysctl_kern_malloc_stats():
> 849    mtsh.mtsh_maxcpus = MAXCPU;
> 
> 1a) memstat_sysctl_malloc()
> left unchanged, sysctl kern.smp.maxcpus
> 1b) memstat_kvm_malloc()
> left unchanged, _mp_maxcpus symbol
> 
> 2) uma stats
> vm.zone_stats uses (mp_maxid + 1), vm/uma_core.c:sysctl_vm_zone_stats():
> 3247    ush.ush_maxcpus = (mp_maxid + 1);
> 
> 2a) memstat_sysctl_uma()
> Switched to query sysctl kern.smp.maxid
> 2b) memstat_kvm_uma()
> left unchanged,  _mp_maxid symbol
> 
> So, there's only one change in memstat_sysctl_uma().
> A bad side of things is that libmemstat() now knows these vm_zone
> and malloc_stats internals.
> As Robert suggested me on IRC to query maxcpu value from
> uma_stream_header and malloc_type_stream_header structures
> respectively to be independent from kernel details.

Looks good to me, thanks!

-- 
John Baldwin