Made a new (inline) function devsw(dev_t dev) and substituted it.
Changed to the BDEV variant to this format as well: bdevsw(dev_t dev)
DEVFS will eventually benefit from this change too.
Virtualize bdevsw[] from cdevsw. bdevsw() is now an (inline)
function.
Join CDEV_MODULE and BDEV_MODULE to DEV_MODULE (please pay attention
to the order of the cmaj/bmaj arguments!)
Join CDEV_DRIVER_MODULE and BDEV_DRIVER_MODULE to DEV_DRIVER_MODULE
(ditto!)
(Next step will be to convert all bdev dev_t's to cdev dev_t's
before they get to do any damage^H^H^H^H^H^Hwork in the kernel.)
piecemeal, middle-of-file writes for NFS. These hacks have caused no
end of trouble, especially when combined with mmap(). I've removed
them. Instead, NFS will issue a read-before-write to fully
instantiate the struct buf containing the write. NFS does, however,
optimize piecemeal appends to files. For most common file operations,
you will not notice the difference. The sole remaining fragment in
the VFS/BIO system is b_dirtyoff/end, which NFS uses to avoid cache
coherency issues with read-merge-write style operations. NFS also
optimizes the write-covers-entire-buffer case by avoiding the
read-before-write. There is quite a bit of room for further
optimization in these areas.
The VM system marks pages fully-valid (AKA vm_page_t->valid =
VM_PAGE_BITS_ALL) in several places, most noteably in vm_fault. This
is not correct operation. The vm_pager_get_pages() code is now
responsible for marking VM pages all-valid. A number of VM helper
routines have been added to aid in zeroing-out the invalid portions of
a VM page prior to the page being marked all-valid. This operation is
necessary to properly support mmap(). The zeroing occurs most often
when dealing with file-EOF situations. Several bugs have been fixed
in the NFS subsystem, including bits handling file and directory EOF
situations and buf->b_flags consistancy issues relating to clearing
B_ERROR & B_INVAL, and handling B_DONE.
getblk() and allocbuf() have been rewritten. B_CACHE operation is now
formally defined in comments and more straightforward in
implementation. B_CACHE for VMIO buffers is based on the validity of
the backing store. B_CACHE for non-VMIO buffers is based simply on
whether the buffer is B_INVAL or not (B_CACHE set if B_INVAL clear,
and vise-versa). biodone() is now responsible for setting B_CACHE
when a successful read completes. B_CACHE is also set when a bdwrite()
is initiated and when a bwrite() is initiated. VFS VOP_BWRITE
routines (there are only two - nfs_bwrite() and bwrite()) are now
expected to set B_CACHE. This means that bowrite() and bawrite() also
set B_CACHE indirectly.
There are a number of places in the code which were previously using
buf->b_bufsize (which is DEV_BSIZE aligned) when they should have
been using buf->b_bcount. These have been fixed. getblk() now clears
B_DONE on return because the rest of the system is so bad about
dealing with B_DONE.
Major fixes to NFS/TCP have been made. A server-side bug could cause
requests to be lost by the server due to nfs_realign() overwriting
other rpc's in the same TCP mbuf chain. The server's kernel must be
recompiled to get the benefit of the fixes.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
1:
s/suser/suser_xxx/
2:
Add new function: suser(struct proc *), prototyped in <sys/proc.h>.
3:
s/suser_xxx(\([a-zA-Z0-9_]*\)->p_ucred, \&\1->p_acflag)/suser(\1)/
The remaining suser_xxx() calls will be scrutinized and dealt with
later.
There may be some unneeded #include <sys/cred.h>, but they are left
as an exercise for Bruce.
More changes to the suser() API will come along with the "jail" code.
unallocated parts of the last page when the file ended on a frag
but not a page boundary.
Delimitted by tags PRE_MATT_MMAP_EOF and POST_MATT_MMAP_EOF,
in files alpha/alpha/pmap.c i386/i386/pmap.c nfs/nfs_bio.c vm/pmap.h
vm/vm_page.c vm/vm_page.h vm/vnode_pager.c miscfs/specfs/spec_vnops.c
ufs/ufs/ufs_readwrite.c kern/vfs_bio.c
Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Alan Cox <alc@freebsd.org>
1. Don't bother checking object->ref_count == 1 in order to set
OBJ_ONEMAPPING. It's a waste of time. If object->ref_count == 1,
vm_map_entry_delete will "run-down" the object and its pages.
2. If object->ref_count == 1, ignore OBJ_ONEMAPPING. Wait for
vm_map_entry_delete to "run-down" the object and its pages.
Otherwise, we're calling two different procedures to delete
the object's pages.
Note: "vmstat -s" will once again show a non-zero value
for "pages freed by exiting processes".
Remove more (redundant) map timestamp increments from properly
synchronized routines. (Changed: vm_map_entry_link, vm_map_entry_unlink,
and vm_map_pageable.)
Micro-optimize vm_map_entry_link and vm_map_entry_unlink, eliminating
unnecessary dereferences. At the same time, converted them from macros
to inline functions.
address) so that the first 16MB of physical memory is allocated
last rather than first. On large-memory machines, this avoids
the exhaustion of low physical memory before isa_dmainit has run.
block (VM_WAIT) holding the map lock. This is bad. For example, a subsequent
kmem_malloc by an interrupt handler on the same map may find the lock held
and panic in the lockmgr.
In general, vm_map_simplify_entry should be performed INSIDE
the loop that traverses the map, not outside. (Changed:
vm_map_inherit, vm_map_pageable.)
vm_fault_unwire doesn't acquire the map lock (or block holding
it). Thus, vm_map_set/clear_recursive shouldn't be called.
(Changed: vm_map_user_pageable, vm_map_pageable.)
The old VN device broke in -4.x when the definition of B_PAGING
changed. This patch fixes this plus implements additional capabilities.
The new VN device can be backed by a file ( as per normal ), or it can
be directly backed by swap.
Due to dependencies in VM include files (on opt_xxx options) the new
vn device cannot be a module yet. This will be fixed in a later commit.
This commit delimitted by tags {PRE,POST}_MATT_VNDEV
1. The size of vm_object::memq is vm_object::resident_page_count,
not vm_object::size.
2. The "size > 4" test sometimes results in the traversal of a ~1000 page
memq in order to locate ~10 pages.
lock) until it actually needs to modify the vm_map.
Note: it is legal to modify vm_map::hint without holding a write lock.
Submitted by: "Richard Seaman, Jr." <dick@tar.com> with minor changes
by myself.
the read lock around the subyte operations in mincore. After the lock is
reacquired, use the map's timestamp to determine if we need to restart
the scan.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
To prevent a deadlock, if we are extremely low on memory, force synchronous
operation by the VOP_PUTPAGES in vnode_pager_putpages.
Fix bug where an object's OBJ_WRITEABLE/OBJ_MIGHTBEDIRTY flags do
not get set under certain circumstances ( page rename case ).
Reviewed by: Alan Cox <alc@cs.rice.edu>, John Dyson
is the preparation step for moving pmap storage out of vmspace proper.
Reviewed by: Alan Cox <alc@cs.rice.edu>
Matthew Dillion <dillon@apollo.backplane.com>
be in progress at any given moment.
Add two swap tuneables to sysctl:
vm.swap_async_max: 4
vm.swap_cluster_max: 16
Recommended values are a cluster size of 8 or 16 pages. async_max is
about right for 1-4 swap devices. Reduce to 2 if swap is eating too much
bandwidth, or even 1 if swap is both eating too much bandwidth and sitting
on a slow network (10BaseT).
The defaults work well across a broad range of configurations and should
normally be left alone.
Unlock vnode before messing with map to avoid deadlock between map and
vnode ( e.g. with exec_map and underlying program binary vnode ). Solves
a deadlock that most often occurs during a large -j# buildworld reported
by three people.
been made but the code has been reorganized and documented to make
it more readable, reduce the size of the code, and optimize the branch
path caching capabilities that most modern processors have.
free swap space out from under a busy page. This is not legal because
the swap may be reallocated and I/O issued while I/O is still in
progress on the same swap page from the madvise()'d object. This bug
could only occur under extreme paging conditions but might not cause
an error until much later. As a side-benefit, madvise() is now even
smaller.
possible without actually unmapping it from the process.
As of now, I declare madvise() on OBJT_DEFAULT/OBJT_SWAP objects to be
'working and complete'.
OBJ_ONEMAPPING in the case where an object is extended by an
additional vm_map_entry must be allocated.
In vm_object_madvise(), remove calll to vm_page_cache() in MADV_FREE
case in order to avoid a page fault on page reuse. However, we still
mark the page as clean and destroy any swap backing store.
Submitted by: Alan Cox <alc@cs.rice.edu>
because there was a concensus on current in regards to leaving bss r+w+x
instead of r+w. This is in order to maintain reasonable compatibility
with existing JIT compilers (e.g. kaffe) and possibly other programs.
no major operational changes were made. The three core object->memq loops
were moved into a single inline procedure and various operational
characteristics of the collapse function were documented.
PQ_FREE. There is little operational difference other then the kernel
being a few kilobytes smaller and the code being more readable.
* vm_page_select_free() has been *greatly* simplified.
* The PQ_ZERO page queue and supporting structures have been removed
* vm_page_zero_idle() revamped (see below)
PG_ZERO setting and clearing has been migrated from vm_page_alloc()
to vm_page_free[_zero]() and will eventually be guarenteed to remain
tracked throughout a page's life ( if it isn't already ).
When a page is freed, PG_ZERO pages are appended to the appropriate
tailq in the PQ_FREE queue while non-PG_ZERO pages are prepended.
When locating a new free page, PG_ZERO selection operates from within
vm_page_list_find() ( get page from end of queue instead of beginning
of queue ) and then only occurs in the nominal critical path case. If
the nominal case misses, both normal and zero-page allocation devolves
into the same _vm_page_list_find() select code without any specific
zero-page optimizations.
Additionally, vm_page_zero_idle() has been revamped. Hysteresis has been
added and zero-page tracking adjusted to conform with the other changes.
Currently hysteresis is set at 1/3 (lo) and 1/2 (hi) the number of free
pages. We may wish to increase both parameters as time permits. The
hysteresis is designed to avoid silly zeroing in borderline allocation/free
situations.
attempt to optimize forks but were essentially given-up on due to
problems and replaced with an explicit dup of the vm_map_entry structure.
Prior to the removal, they were entirely unused.
rather then VM_PROT_ALL. obreak, on the otherhand, uses VM_PROT_ALL.
This prevents vm_map_insert() from being able to coalesce the heap and
creates an extra map entry. Since current architectures ignore
VM_PROT_EXECUTE anyway, and since not having VM_PROT_EXECUTE on data/bss
may provide protection in the future, obreak now uses read+write rather
then all (r+w+x).
This is an optimization, not a bug fix.
Submitted by: Alan Cox <alc@cs.rice.edu>
Since paging is in progress, page scan in vm_page_qcollapse() must be
protected at atleast splbio() to prevent pages from being ripped out from
under the scan.
The vm_map_insert()/vm_object_coalesce() optimization has been extended
to include OBJT_SWAP objects as well as OBJT_DEFAULT objects. This is
possible because it costs nothing to extend an OBJT_SWAP object with
the new swapper. We can't do this with the old swapper. The old swapper
used a linear array that would have had to have been reallocated, costing
time as well as a potential low-memory deadlock.
in vm_map_simplify_entry. Basically, once you've verified that
the objects in the adjacent vm_map_entry's are the same, either
NULL or the same vm_object, there's no point in checking that the
objects have the same behavior.
Obtained from: Alan Cox <alc@cs.rice.edu>
Checked by: "Richard Seaman, Jr." <dick@tar.com>
Fix the following problem:
As the code stands now, growing any stack, and not just the process's
main stack, modifies vm->vm_ssize. This is inconsistent with the code
earlier in the same procedure.
This changes the definitions of a few items so that structures are the
same whether or not the option itself is enabled. This allows
people to enable and disable the option without recompilng the world.
As the author says:
|I ran into a problem pulling out the VM_STACK option. I was aware of this
|when I first did the work, but then forgot about it. The VM_STACK stuff
|has some code changes in the i386 branch. There need to be corresponding
|changes in the alpha branch before it can come out completely.
what is done:
|
|1) Pull the VM_STACK option out of the header files it appears in. This
|really shouldn't affect anything that executes with or without the rest
|of the VM_STACK patches. The vm_map_entry will then always have one
|extra element (avail_ssize). It just won't be used if the VM_STACK
|option is not turned on.
|
|I've also pulled the option out of vm_map.c. This shouldn't harm anything,
|since the routines that are enabled as a result are not called unless
|the VM_STACK option is enabled elsewhere.
|
|2) Add what appears to be appropriate code the the alpha branch, still
|protected behind the VM_STACK switch. I don't have an alpha machine,
|so we would need to get some testers with alpha machines to try it out.
|
|Once there is some testing, we can consider making the change permanent
|for both i386 and alpha.
|
[..]
|
|Once the alpha code is adequately tested, we can pull VM_STACK out
|everywhere.
|
Submitted by: "Richard Seaman, Jr." <dick@tar.com>
This takes the conditionals out of the code that has been tested by
various people for a while.
ps and friends (libkvm) will need a recompile as some proc structure
changes are made.
Submitted by: "Richard Seaman, Jr." <dick@tar.com>
vm_page_rename(), but never pulled the page off PQ_CACHE if it was on
PQ_CACHE. Dirty pages in PQ_CACHE are not allowed and a KASSERT was
added in -4.x to test for this... and got hit.
In -4.x, vm_page_rename() automatically dirties the page. This commit
also has it deal with the PQ_CACHE case, deactivating the page in that
case.
values. The 'int' return value for the procedure was never used and
not well defined in any case when there are mixed errors on pages, so
it has been removed. vm_pager_put_pages() and associated vm_pager
functions now return void.
swap blocks are now in PAGE_SIZE'd increments instead of DEV_BSIZE'd
increments. We still convert to DEV_BSIZE'd increments for the
backing store I/O, but everything else is in PAGE_SIZE increments.
vm_pager.h
Added argument to getpbuf() and relpbuf() to allow each subsystem to
specify a different hard limit on the number of simultanious physical
bufferes that said subsystem may allocate. Without this feature, one
subsystem ( e.g. the vfs clustering code ) could hog *ALL* the pbufs,
causing a deadlock in the pager in a low memory situation.
Same for trypbuf().
Removed call to vm_object_collapse(), which can block. This was being
called without the pageout code holding any sort of reference on the
vm_object or vm_page_t structures being manipulated. Since this code
can block, it was possible for other kernel code to shred the state
the pageout code was assuming remained intact.
Fixed potential blocking condition in vm_pageout_page_free() ( which
could cause a deadlock in a low-memory situation ).
Currently there is a hack in-place to deal with clean filesystem meta-data
polluting the inactive page queue. John doesn't like the hack, and neither
do I.
Revamped and commented a portion of the pageout loop.
Added protection against potential memory deadlocks with OBJT_VNODE
when using VOP_ISLOCKED(). The problem is that vp->v_data can be NULL
which causes VOP_ISLOCKED() to return a less informed answer.
remove vm_pager_sync() -- none of the pagers use it any more ( the old
swapper used to. The new one does not ).
reducing the size of vm_page_t.
SWAPBLK_NONE and SWAPBLK_MASK are defined here. These actually are
more generalized then their names imply, but their placement is somewhat
of a legacy issue from a prior test version of this code that put
the swapblk in the vm_page_t structure. That test code was eventually
thrown away. The legacy remains.
Added vm_page_flash() inline. Similar to vm_page_wakeup() except that
it does not clear PG_BUSY ( one assumes that PG_BUSY is already clear ).
Used by a number of routines to wakeup waiters.
Collapsed some of the code in inline calls to make other inline calls.
GCC will optimize this well and it reduces duplication.
vm_page_free() and vm_page_free_zero() inlines added to convert to
the proper vm_page_free_toq() call.
vm_page_sleep_busy() inline added, replacing vm_page_sleep() ( which has
been removed ). This implements a much more optimizable page-waiting
function.
pointers per entry ). The table has been changed to a singly linked
list of vm_page_t pointers. The table has been doubled in size, but
the entries only take half the space so a net-zero change in memory use.
The hash function has been changed, hopefully for the better. The
combination of the larger hash table size of changed function should
keep the chain length down to a reasonable number (0-3, average 1).
vm_object->page_hint has been removed. This 'optimization' was not
only never needed, but costs as much as a hash chain link to implement.
While having page_hint in vm_object might result in better locality
of reference, the cost is not worth the space in vm_object or the
extra instructions in my view.
vm_page_alloc*() functions have been inlined and call a generalized
non-inlined vm_page_alloc_toq() which combines the standard alloc
and zero-page alloc functions together, reducing code size and the L1
cache footprint. Some reordering has been done... not much. The
delinking code should be faster ( because unlinking a doubly-linked list
requires four memory ops and unlinking a singly linked list only requires
two ), and we get a hash consistancy check for free.
vm_page_rename() now automatically sets the page's dirty bits.
vm_page_alloc() does not try to manually inline freeing a cache page.
Instead, it now properly calls vm_page_free(m) ... vm_page_free() is
really too complex to manually inline.
vm_await(), supporting asleep(), has been added.
of most of the swap-pager-specific fields, the removal of the id,
and the removal of paging_offset.
A new inline, vm_object_pip_wakeupn() has been added to subtract an
arbitrary number n from the paging_in_progress count and then wakeup
waiters as necessary. n may be 0, resulting in a 'flash'.
object->paging_offset has been removed - it was used to optimize a
single OBJT_SWAP collapse case yet introduced massive confusion throughout
vm_object.c. The optimization was inconsequential except for the
claim that it didn't have to allocate any memory. The optimization
has been removed.
madvise() has been fixed. The old madvise() could be made to operate
on shared objects which is a big no-no. The new one is much more careful
in what it modifies. MADV_FREE was totally broken and has now been fixed.
vm_page_rename() now automatically dirties a page, so explicit dirtying
of the page prior to calling vm_page_rename() has been removed.
about conversions of objects to OBJT_SWAP, it is done automatically
now.
Replaced manually inserted code with inline calls for busy waiting on
pages, which also incidently fixes a potential PG_BUSY race due to
the code not running at splvm().
vm_objects no longer have a paging_offset field ( see vm/vm_object.c )
instead to properly handle any waiters.
Added comments, added support for M_ASLEEP. Generally treat M_ flags
as flags instead of constants to compare against.
