the loadav. This is not real load. If you have a nice process running in
the background, pagezero may sit in the run queue for ages and add one to
the loadav, and thereby affecting other scheduling decisions.
that pre-zeroes free pages.
o Remove GIANT_REQUIRED from some low-level page queue functions. (Instead
assertions on the page queue lock are being added to the higher-level
functions, like vm_page_wire(), etc.)
In collaboration with: peter
vm_page_zero_idle() instead of partially duplicated implementations.
In particular, this change guarantees that the number of free pages
in the free queue(s) matches the global free page count when Giant
is released.
Submitted by: peter (via his p4 "pmap" branch)
page-zeroing code as well as from the general page-zeroing code and use a
lazy tlb page invalidation scheme based on a callback made at the end
of mi_switch.
A number of people came up with this idea at the same time so credit
belongs to Peter, John, and Jake as well.
Two-way SMP buildworld -j 5 tests (second run, after stabilization)
2282.76 real 2515.17 user 704.22 sys before peter's IPI commit
2266.69 real 2467.50 user 633.77 sys after peter's commit
2232.80 real 2468.99 user 615.89 sys after this commit
Reviewed by: peter, jhb
Approved by: peter
I do not know why this didn't panic my box, but I have most certainly
been using it:
peter@overcee[3:14pm]~src/sys/i386/i386-110> sysctl -a | grep zero
vm.stats.misc.zero_page_count: 2235
vm.stats.misc.cnt_prezero: 638951
vm.idlezero_enable: 1
vm.idlezero_maxrun: 16
Submitted by: Tor.Egge@cvsup.no.freebsd.org
Approved by: Tor's patches are never wrong. :-)
TLB problem when bouncing from one cpu to another (the original cpu will
not have purged its TLB if the it simply went idle).
Pointed out by: Tor.Egge@cvsup.no.freebsd.org
Approved by: Tor is never wrong. :-)
threaded VM pagezero kthread outside of Giant. For some platforms, this
is really easy since it can just use the direct mapped region. For others,
IPI sending is involved or there are other issues, so grab Giant when
needed.
We still have preemption issues to deal with, but Alan Cox has an
interesting suggestion on how to minimize the problem on x86.
Use Luigi's hack for preserving the (lack of) priority.
Turn the idle zeroing back on since it can now actually do something useful
outside of Giant in many cases.
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)
Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)
NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..
and pmap_copy_page(). This gets rid of a couple more physical addresses
in upper layers, with the eventual aim of supporting PAE and dealing with
the physical addressing mostly within pmap. (We will need either 64 bit
physical addresses or page indexes, possibly both depending on the
circumstances. Leaving this to pmap itself gives more flexibilitly.)
Reviewed by: jake
Tested on: i386, ia64 and (I believe) sparc64. (my alpha was hosed)
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
on and off since John Dyson left his work-in-progress.
It is off by default for now. sysctl vm.zeroidle_enable=1 to turn it on.
There are some hacks here to deal with the present lack of preemption - we
yield after doing a small number of pages since we wont preempt otherwise.
This is basically Matt's algorithm [with hysteresis] with an idle process
to call it in a similar way it used to be called from the idle loop.
I cleaned up the includes a fair bit here too.
