pmap_zero_page() and pmap_zero_page_area() were modified to accept
a struct vm_page * instead of a physical address, vm_page_zero_fill()
and vm_page_zero_fill_area() have served no purpose.
- v_vflag is protected by the vnode lock and is used when synchronization
with VOP calls is needed.
- v_iflag is protected by interlock and is used for dealing with vnode
management issues. These flags include X/O LOCK, FREE, DOOMED, etc.
- All accesses to v_iflag and v_vflag have either been locked or marked with
mp_fixme's.
- Many ASSERT_VOP_LOCKED calls have been added where the locking was not
clear.
- Many functions in vfs_subr.c were restructured to provide for stronger
locking.
Idea stolen from: BSD/OS
by pmap_qenter() and pmap_qremove() is pointless. In fact, it probably
leads to unnecessary pmap_page_protect() calls if one of these pages is
paged out after unwiring.
Note: setting PG_MAPPED asserts that the page's pv list may be
non-empty. Since checking the status of the page's pv list isn't any
harder than checking this flag, the flag should probably be eliminated.
Alternatively, PG_MAPPED could be set by pmap_enter() exclusively
rather than various places throughout the kernel.
vm_page_sleep_busy() with vm_page_sleep_if_busy(). At the same time,
increase the scope of the page queues lock. (This should significantly
reduce the locking overhead in vm_object_page_remove().)
o Apply some style fixes.
swapped in, we do not have to ask for the scheduler thread to do
that.
- Assert that a process is not swapped out in runq functions and
swapout().
- Introduce thread_safetoswapout() for readability.
- In swapout_procs(), perform a test that may block (check of a
thread working on its vm map) first. This lets us call swapout()
with the sched_lock held, providing a better atomicity.
except for the fact tha they are presently swapped out. Also add a process
flag to indicate that the process has started the struggle to swap
back in. This will be needed for the case where multiple threads
start the swapin action top a collision. Also add code to stop
a process fropm being swapped out if one of the threads in this
process is actually off running on another CPU.. that might hurt...
Submitted by: Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp>
vm_page_rename() from vm_object_backing_scan(). vm_page_rename()
also performs vm_page_deactivate() on pages in the cache queues,
making the removed vm_page_deactivate() redundant.
handler in the kernel at the same time. Also, allow for the
exec_new_vmspace() code to build a different sized vmspace depending on
the executable environment. This is a big help for execing i386 binaries
on ia64. The ELF exec code grows the ability to map partial pages when
there is a page size difference, eg: emulating 4K pages on 8K or 16K
hardware pages.
Flesh out the i386 emulation support for ia64. At this point, the only
binary that I know of that fails is cvsup, because the cvsup runtime
tries to execute code in pages not marked executable.
Obtained from: dfr (mostly, many tweaks from me).
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.
when VM_ALLOC_WIRED is specified: set the PG_MAPPED bit in flags.
o In both vm_page_wire() and vm_page_allocate() add a comment saying
that setting PG_MAPPED does not belong there.
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
Use lmin(long, long), not min(u_int, u_int). This is a problem here on
ia64 which has *way* more than 2^32 pages of KVA. 281474976710655 pages
to be precice.
to return a wired page.
o Use VM_ALLOC_WIRED within Alpha's pmap_growkernel(). Also, because
Alpha's pmap_growkernel() calls vm_page_alloc() from within a critical
section, specify VM_ALLOC_INTERRUPT instead of VM_ALLOC_SYSTEM. (Only
VM_ALLOC_INTERRUPT is implemented entirely with a spin mutex.)
o Assert that the page queues mutex is held in vm_page_wire()
on Alpha, just like the other platforms.
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)
o Assert that the page queues lock is held in vm_page_unwire().
o Make vm_page_lock_queues() and vm_page_unlock_queues() visible
to kernel loadable modules.
_vm_map_lock_read(), and _vm_map_trylock(). Submitted by: tegge
o Remove GIANT_REQUIRED from kmem_alloc_wait() and kmem_free_wakeup().
(This clears the way for exec_map accesses to move outside of Giant.
The exec_map is not a system map.)
o Remove some premature MPSAFE comments.
Reviewed by: tegge
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
and kmem_free_wakeup(). Previously, kmem_free_wakeup() always
called wakeup(). In general, no one was sleeping.
o Export vm_map_unlock_and_wait() and vm_map_wakeup() from vm_map.c
for use in vm_kern.c.
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.
pmap_swapin_proc/pmap_swapout_proc functions from the MD pmap code
and use a single equivalent MI version. There are other cleanups
needed still.
While here, use the UMA zone hooks to keep a cache of preinitialized
proc structures handy, just like the thread system does. This eliminates
one dependency on 'struct proc' being persistent even after being freed.
There are some comments about things that can be factored out into
ctor/dtor functions if it is worth it. For now they are mostly just
doing statistics to get a feel of how it is working.
vm_mmap() as well as the GETATTR etc.
- If the handle is a vnode in vm_mmap() assert that it is locked.
- Wiggle Giant around a little to account for the extra vnode operation.
queue lock (revision 1.33 of vm/vm_page.c removed them).
o Make the free queue lock a spin lock because it's sometimes acquired
inside of a critical section.
of the KVA space's size in addition to the amount of physical memory
and reduce it by a factor of two.
Under the old formula, our reservation amounted to one kernel map entry
per virtual page in the KVA space on a 4GB i386.
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..
types are not required, as the overhead is unnecessary:
o In the i386 pmap_protect(), `sindex' and `eindex' represent page
indices within the 32-bit virtual address space.
o In swp_pager_meta_build() and swp_pager_meta_ctl(), use a temporary
variable to store the low few bits of a vm_pindex_t that gets used
as an array index.
o vm_uiomove() uses `osize' and `idx' for page offsets within a
map entry.
o In vm_object_split(), `idx' is a page offset within a map entry.
MAKEDEV: Add MAKEDEV glue for the ti(4) device nodes.
ti.4: Update the ti(4) man page to include information on the
TI_JUMBO_HDRSPLIT and TI_PRIVATE_JUMBOS kernel options,
and also include information about the new character
device interface and the associated ioctls.
man9/Makefile: Add jumbo.9 and zero_copy.9 man pages and associated
links.
jumbo.9: New man page describing the jumbo buffer allocator
interface and operation.
zero_copy.9: New man page describing the general characteristics of
the zero copy send and receive code, and what an
application author should do to take advantage of the
zero copy functionality.
NOTES: Add entries for ZERO_COPY_SOCKETS, TI_PRIVATE_JUMBOS,
TI_JUMBO_HDRSPLIT, MSIZE, and MCLSHIFT.
conf/files: Add uipc_jumbo.c and uipc_cow.c.
conf/options: Add the 5 options mentioned above.
kern_subr.c: Receive side zero copy implementation. This takes
"disposable" pages attached to an mbuf, gives them to
a user process, and then recycles the user's page.
This is only active when ZERO_COPY_SOCKETS is turned on
and the kern.ipc.zero_copy.receive sysctl variable is
set to 1.
uipc_cow.c: Send side zero copy functions. Takes a page written
by the user and maps it copy on write and assigns it
kernel virtual address space. Removes copy on write
mapping once the buffer has been freed by the network
stack.
uipc_jumbo.c: Jumbo disposable page allocator code. This allocates
(optionally) disposable pages for network drivers that
want to give the user the option of doing zero copy
receive.
uipc_socket.c: Add kern.ipc.zero_copy.{send,receive} sysctls that are
enabled if ZERO_COPY_SOCKETS is turned on.
Add zero copy send support to sosend() -- pages get
mapped into the kernel instead of getting copied if
they meet size and alignment restrictions.
uipc_syscalls.c:Un-staticize some of the sf* functions so that they
can be used elsewhere. (uipc_cow.c)
if_media.c: In the SIOCGIFMEDIA ioctl in ifmedia_ioctl(), avoid
calling malloc() with M_WAITOK. Return an error if
the M_NOWAIT malloc fails.
The ti(4) driver and the wi(4) driver, at least, call
this with a mutex held. This causes witness warnings
for 'ifconfig -a' with a wi(4) or ti(4) board in the
system. (I've only verified for ti(4)).
ip_output.c: Fragment large datagrams so that each segment contains
a multiple of PAGE_SIZE amount of data plus headers.
This allows the receiver to potentially do page
flipping on receives.
if_ti.c: Add zero copy receive support to the ti(4) driver. If
TI_PRIVATE_JUMBOS is not defined, it now uses the
jumbo(9) buffer allocator for jumbo receive buffers.
Add a new character device interface for the ti(4)
driver for the new debugging interface. This allows
(a patched version of) gdb to talk to the Tigon board
and debug the firmware. There are also a few additional
debugging ioctls available through this interface.
Add header splitting support to the ti(4) driver.
Tweak some of the default interrupt coalescing
parameters to more useful defaults.
Add hooks for supporting transmit flow control, but
leave it turned off with a comment describing why it
is turned off.
if_tireg.h: Change the firmware rev to 12.4.11, since we're really
at 12.4.11 plus fixes from 12.4.13.
Add defines needed for debugging.
Remove the ti_stats structure, it is now defined in
sys/tiio.h.
ti_fw.h: 12.4.11 firmware.
ti_fw2.h: 12.4.11 firmware, plus selected fixes from 12.4.13,
and my header splitting patches. Revision 12.4.13
doesn't handle 10/100 negotiation properly. (This
firmware is the same as what was in the tree previously,
with the addition of header splitting support.)
sys/jumbo.h: Jumbo buffer allocator interface.
sys/mbuf.h: Add a new external mbuf type, EXT_DISPOSABLE, to
indicate that the payload buffer can be thrown away /
flipped to a userland process.
socketvar.h: Add prototype for socow_setup.
tiio.h: ioctl interface to the character portion of the ti(4)
driver, plus associated structure/type definitions.
uio.h: Change prototype for uiomoveco() so that we'll know
whether the source page is disposable.
ufs_readwrite.c:Update for new prototype of uiomoveco().
vm_fault.c: In vm_fault(), check to see whether we need to do a page
based copy on write fault.
vm_object.c: Add a new function, vm_object_allocate_wait(). This
does the same thing that vm_object allocate does, except
that it gives the caller the opportunity to specify whether
it should wait on the uma_zalloc() of the object structre.
This allows vm objects to be allocated while holding a
mutex. (Without generating WITNESS warnings.)
vm_object_allocate() is implemented as a call to
vm_object_allocate_wait() with the malloc flag set to
M_WAITOK.
vm_object.h: Add prototype for vm_object_allocate_wait().
vm_page.c: Add page-based copy on write setup, clear and fault
routines.
vm_page.h: Add page based COW function prototypes and variable in
the vm_page structure.
Many thanks to Drew Gallatin, who wrote the zero copy send and receive
code, and to all the other folks who have tested and reviewed this code
over the years.
a new resource limit that covers a process's entire VM space, including
mmap()'d space.
(Part II will be additional code to check RLIMIT_VMEM during exec() but it
needs more fleshing out).
PR: kern/18209
Submitted by: Andrey Alekseyev <uitm@zenon.net>, Dmitry Kim <jason@nichego.net>
MFC after: 7 days
64-bit file sizes. This step simply addresses the remaining overflows,
and does attempt to optimise performance. The details are:
o Use a 64-bit type for the vm_object `size' and the size argument
to vm_object_allocate().
o Use the correct type for index variables in dev_pager_getpages(),
vm_object_page_clean() and vm_object_page_remove().
o Avoid an overflow in the i386 pmap_object_init_pt().
with the acquisition and release of Giant. (Annotate as MPSAFE.)
o Reorder the sanity checks in dev_pager_alloc() to reduce
the time that Giant is held.
release of Giant around the direct manipulation of the vm_object and
the optional call to pmap_object_init_pt().
o In vm_map_findspace(), remove GIANT_REQUIRED. Instead, acquire and
release Giant around the occasional call to pmap_growkernel().
o In vm_map_find(), remove GIANT_REQUIRED.
release of Giant. (Annotate as MPSAFE.)
o Also, in vnode_pager_alloc(), remove an unnecessary re-initialization
of struct vm_object::flags and move a statement that is duplicated
in both branches of an if-else.
for example, break an sbrk(>=4GB) on 64-bit architectures
even if the resource limit allowed it.
o Correct an off-by-one error.
o Correct a spelling error in a comment.
o Reorder an && expression so that the commonly FALSE expression
comes first.
Submitted by: bde (bullets 1 and 2)
Consequently, use vm_map_insert() and vm_map_delete(), which expect
the vm_map to be locked, instead of vm_map_find() and vm_map_remove(),
which do not.
allocator.
- Properly set M_ZERO when talking to the back end page allocators for
non malloc zones. This forces us to zero fill pages when they are first
brought into a cache.
- Properly handle M_ZERO in uma_zalloc_internal. This fixes a problem where
per cpu buckets weren't always getting zeroed.
release of Giant.
o Reduce the scope of GIANT_REQUIRED in vm_map_insert().
These changes will enable us to remove the acquisition and release
of Giant from obreak().
allocated slabs and bucket caches for free items. It will not go ask the vm
for pages. This differs from M_NOWAIT in that it not only doesn't block, it
doesn't even ask.
- Add a new zcreate option ZONE_VM, that sets the BUCKETCACHE zflag. This
tells uma that it should only allocate buckets out of the bucket cache, and
not from the VM. It does this by using the M_NOVM option to zalloc when
getting a new bucket. This is so that the VM doesn't recursively enter
itself while trying to allocate buckets for vm_map_entry zones. If there
are already allocated buckets when we get here we'll still use them but
otherwise we'll skip it.
- Use the ZONE_VM flag on vm map entries and pv entries on x86.
o Move pmap_pageable() outside of Giant in vm_fault_unwire().
(pmap_pageable() is a no-op on all supported architectures.)
o Remove the acquisition and release of Giant from mlock().
vm_map_user_pageable().
o Remove vm_map_pageable() and vm_map_user_pageable().
o Remove vm_map_clear_recursive() and vm_map_set_recursive(). (They were
only used by vm_map_pageable() and vm_map_user_pageable().)
Reviewed by: tegge
Submitted by: tegge
o Eliminate the "!mapentzone" check from vm_map_entry_create() and
vm_map_entry_dispose(). Reviewed by: tegge
o Fix white-space usage in vm_map_entry_create().
or user vm_maps. This implementation has two key benefits when compared
to vm_map_{user_,}pageable(): (1) it avoids a race condition through
the use of "in-transition" vm_map entries and (2) it eliminates lock
recursion on the vm_map.
Note: there is still an error case that requires clean up.
Reviewed by: tegge
o Add a stub for vm_map_wire().
Note: the description of the previous commit had an error. The in-
transition flag actually blocks the deallocation of a vm_map_entry by
vm_map_delete() and vm_map_simplify_entry().
or user vm_maps. In accordance with the standards for munlock(2),
and in contrast to vm_map_user_pageable(), this implementation does not
allow holes in the specified region. This implementation uses the
"in transition" flag described below.
o Introduce a new flag, "in transition," to the vm_map_entry.
Eventually, vm_map_delete() and vm_map_simplify_entry() will respect
this flag by deallocating in-transition vm_map_entrys, allowing
the vm_map lock to be safely released in vm_map_unwire() and (the
forthcoming) vm_map_wire().
o Modify vm_map_simplify_entry() to respect the in-transition flag.
In collaboration with: tegge
vm_map_create(), and vm_map_submap().
o Make further use of a local variable in vm_map_entry_splay()
that caches a reference to one of a vm_map_entry's children.
(This reduces code size somewhat.)
o Revert a part of revision 1.66, deinlining vmspace_pmap().
(This function is MPSAFE.)
deinlining vm_map_entry_behavior() and vm_map_entry_set_behavior()
actually increases the kernel's size.
o Make vm_map_entry_set_behavior() static and add a comment describing
its purpose.
o Remove an unnecessary initialization statement from vm_map_entry_splay().
into the vm_object layer:
o Acquire and release Giant in vm_object_shadow() and
vm_object_page_remove().
o Remove the GIANT_REQUIRED assertion preceding vm_map_delete()'s call
to vm_object_page_remove().
o Remove the acquisition and release of Giant around vm_map_lookup()'s
call to vm_object_shadow().
and vm_map_delete(). Assert GIANT_REQUIRED in vm_map_delete()
only if operating on the kernel_object or the kmem_object.
o Remove GIANT_REQUIRED from vm_map_remove().
o Remove the acquisition and release of Giant from munmap().
the last accessed datum is moved to the root of the splay tree.
Therefore, on lookups in which the hint resulted in O(1) access,
the splay tree still achieves O(1) access. In contrast, on lookups
in which the hint failed miserably, the splay tree achieves amortized
logarithmic complexity, resulting in dramatic improvements on vm_maps
with a large number of entries. For example, the execution time
for replaying an access log from www.cs.rice.edu against the thttpd
web server was reduced by 23.5% due to the large number of files
simultaneously mmap()ed by this server. (The machine in question has
enough memory to cache most of this workload.)
Nothing comes for free: At present, I see a 0.2% slowdown on "buildworld"
due to the overhead of maintaining the splay tree. I believe that
some or all of this can be eliminated through optimizations
to the code.
Developed in collaboration with: Juan E Navarro <jnavarro@cs.rice.edu>
Reviewed by: jeff
that td_intr_nesting_level is 0 (like malloc() does). Since malloc() calls
uma we can probably remove the check in malloc() for this now. Also,
perform an extra witness check in that case to make sure we don't hold
any locks when performing a M_WAITOK allocation.
release Giant around vm_map_madvise()'s call to pmap_object_init_pt().
o Replace GIANT_REQUIRED in vm_object_madvise() with the acquisition
and release of Giant.
o Remove the acquisition and release of Giant from madvise().
several reasons before. Fixing it involved restructuring the generic hash
code to require calling code to handle locking, unlocking, and freeing hashes
on error conditions.
vm_object_deallocate(), replacing the assertion GIANT_REQUIRED.
o Remove GIANT_REQUIRED from vm_map_protect() and vm_map_simplify_entry().
o Acquire and release Giant around vm_map_protect()'s call to pmap_protect().
Altogether, these changes eliminate the need for mprotect() to acquire
and release Giant.
mallochash. Mallochash is going to go away as soon as I introduce the
kfree/kmalloc api and partially overhaul the malloc wrapper. This can't happen
until all users of the malloc api that expect memory to be aligned on the size
of the allocation are fixed.
Implement the following checks on freed memory in the bucket path:
- Slab membership
- Alignment
- Duplicate free
This previously was only done if we skipped the buckets. This code will slow
down INVARIANTS a bit, but it is smp safe. The checks were moved out of the
normal path and into hooks supplied in uma_dbg.
0xdeadc0de and then check for it just before memory is handed off as part
of a new request. This will catch any post free/pre alloc modification of
memory, as well as introduce errors for anything that tries to dereference
it as a pointer.
This code takes the form of special init, fini, ctor and dtor routines that
are specificly used by malloc. It is in a seperate file because additional
debugging aids will want to live here as well.
mutex class. Currently this is only used for kmapentzone because kmapents
are are potentially allocated when freeing memory. This is not dangerous
though because no other allocations will be done while holding the
kmapentzone lock.
i386/ia64/alpha - catch up to sparc64/ppc:
- replace pmap_kernel() with refs to kernel_pmap
- change kernel_pmap pointer to (&kernel_pmap_store)
(this is a speedup since ld can set these at compile/link time)
all platforms (as suggested by jake):
- gc unused pmap_reference
- gc unused pmap_destroy
- gc unused struct pmap.pm_count
(we never used pm_count - we track address space sharing at the vmspace)
in the same style as sys/proc.h.
o Undo the de-inlining of several trivial, MPSAFE methods on the vm_map.
(Contrary to the commit message for vm_map.h revision 1.66 and vm_map.c
revision 1.206, de-inlining these methods increased the kernel's size.)
due to conditions that suggest the possible need for stack growth.
This has two beneficial effects: (1) we can
now remove calls to vm_map_growstack() from the MD trap handlers and (2)
simple page faults are faster because we no longer unnecessarily perform
vm_map_growstack() on every page fault.
o Remove vm_map_growstack() from the i386's trap_pfault().
o Remove the acquisition and release of Giant from i386's trap_pfault().
(vm_fault() still acquires it.)
statclock can access it in the tail end of statclock_process() at an
unfortunate time. This bit me several times on an SMP alpha (UP2000)
and the problem went away with this change. I'm not sure why it doesn't
break x86 as well. Maybe it's because the clocks are much faster
on alpha (HZ=1024 by default).
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)
