The demise of vm_pager_map_page() in revision 1.93 of vm/vm_pager.c permits
the reduction of the pager map's size by 8M bytes. In other words, eight
megabytes of largely wasted KVA are returned to t

The demise of vm_pager_map_page() in revision 1.93 of vm/vm_pager.c permits
the reduction of the pager map's size by 8M bytes. In other words, eight
megabytes of largely wasted KVA are returned to the kernel map for use
elsewhere.

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Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Eliminate vm_pager_map_page() and vm_pager_unmap_page() and their uses.
Use sf_buf_alloc() and sf_buf_free() instead.

- Push down Giant from vm_pageout() to vm_pageout_scan(), freeing
vm_pageout_page_stats() from Giant.
- Modify vm_pager_put_pages() and vm_pager_page_unswapped() to expect the
vm object to be

- Push down Giant from vm_pageout() to vm_pageout_scan(), freeing
vm_pageout_page_stats() from Giant.
- Modify vm_pager_put_pages() and vm_pager_page_unswapped() to expect the
vm object to be locked on entry. (All of the pager routines now expect
this.)

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Add XXX: comment to vm_pager_unswapped().

Use sparse struct initialization for struct pagerops.

Mark our buffers B_KEEPGIANT before sending them downstream.

Remove swap_pager_strategy implementation.

Move extern declaration of the various pagerops from vm_pager.c
to vm_pager.h where the various pagers will also see them.

Assert that the vm object is locked on entry to vm_pager_get_pages().

Maintain a lock on the vm object of interest throughout vm_fault(),
releasing the lock only if we are about to sleep (e.g., vm_pager_get_pages()
or vm_pager_has_pages()). If we sleep, we have marked

Maintain a lock on the vm object of interest throughout vm_fault(),
releasing the lock only if we are about to sleep (e.g., vm_pager_get_pages()
or vm_pager_has_pages()). If we sleep, we have marked the vm object with
the paging-in-progress flag.

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Add vm object locking to various pagers' "get pages" methods, i386 stack
management functions, and a u area management function.

Allow the VM object flushing code to cluster. When the filesystem syncer
comes along and flushes a file which has been mmap()'d SHARED/RW, with
dirty pages, it was flushing the underlying VM object

Allow the VM object flushing code to cluster. When the filesystem syncer
comes along and flushes a file which has been mmap()'d SHARED/RW, with
dirty pages, it was flushing the underlying VM object asynchronously,
resulting in thousands of 8K writes. With this change the VM Object flushing
code will cluster dirty pages in 64K blocks.

Note that until the low memory deadlock issue is reviewed, it is not safe
to allow the pageout daemon to use this feature. Forced pageouts still
use fs block size'd ops for the moment.

MFC after: 3 days

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o Remove some long dead code: from revision 1.41 of vm/vm_pager.c
3+ years ago.
o Remove some unused prototypes.

Remove __P.

- Remove a number of extra newlines that do not belong here according to
style(9)
- Minor space adjustment in cases where we have "( ", " )", if(), return(),
while(), for(), etc.
- Add /* SYMBOL

- Remove a number of extra newlines that do not belong here according to
style(9)
- Minor space adjustment in cases where we have "( ", " )", if(), return(),
while(), for(), etc.
- Add /* SYMBOL */ after a few #endifs.

Reviewed by: alc

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With Alfred's permission, remove vm_mtx in favor of a fine-grained approach
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to

With Alfred's permission, remove vm_mtx in favor of a fine-grained approach
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.

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Introduce a global lock for the vm subsystem (vm_mtx).

vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems ca

Introduce a global lock for the vm subsystem (vm_mtx).

vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems can now call the base page allocators safely.

Almost all atomic ops were removed as they are covered under the
vm mutex.

Alpha and ia64 now need to catch up to i386's trap handlers.

FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).

Reviewed (partially) by: jake, jhb

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protect pbufs and associated counts with a mutex

Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by: msmith and others

Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by: phk
Reviewed by: phk
Approved by: mdodd

Convert the vm_pager_strategy() interface to take a struct bio instead of
a struct buf. Don't try to examine B_ASYNC, it is a layering violation
to do so. The only current user of this interface is

Convert the vm_pager_strategy() interface to take a struct bio instead of
a struct buf. Don't try to examine B_ASYNC, it is a layering violation
to do so. The only current user of this interface is vn(4) which, since
it emulates a disk interface, operates on struct bio already.

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Move and staticize the bufchain functions so they become local to the
only piece of code using them. This will ease a rewrite of them.

Add necessary spl protection for swapper. The problem was located by
Alfred while testing his SPLASSERT stuff. This is not a complete fix,
more protections are probably needed.

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is cons

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

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$Id$ -> $FreeBSD$

The VFS/BIO subsystem contained a number of hacks in order to optimize
piecemeal, middle-of-file writes for NFS. These hacks have caused no
end of trouble, especially when combined with mmap(). I'v

The VFS/BIO subsystem contained a number of hacks in order to optimize
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>

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