src/sys/vm/vm_fault.c, branch release/4.1.0_cvs

This commit was manufactured by cvs2svn to create tag

2000-07-26T21:12:35Z

'RELENG_4_1_0_RELEASE'. This commit was manufactured to restore the state of the 4.1-RELEASE image. Releases prior to 5.3-RELEASE are omitting the secure/ and crypto/ subdirs.

Add MAP_NOSYNC feature to mmap(), and MADV_NOSYNC and MADV_AUTOSYNC to

1999-12-12T03:19:33Z

madvise(). This feature prevents the update daemon from gratuitously flushing dirty pages associated with a mapped file-backed region of memory. The system pager will still page the memory as necessary and the VM system will still be fully coherent with the filesystem. Modifications made by other means to the same area of memory, for example by write(), are unaffected. The feature works on a page-granularity basis. MAP_NOSYNC allows one to use mmap() to share memory between processes without incuring any significant filesystem overhead, putting it in the same performance category as SysV Shared memory and anonymous memory. Reviewed by: julian, alc, dg

useracc() the prequel:

1999-10-29T18:09:36Z

Merge the contents (less some trivial bordering the silly comments) of and into . This puts the #defines for the vm_inherit_t and vm_prot_t types next to their typedefs. This paves the road for the commit to follow shortly: change useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE} as argument.

Final commit to remove vnode->v_lastr. vm_fault now handles read

1999-09-21T00:36:16Z

clustering issues (replacing code that used to be in ufs/ufs/ufs_readwrite.c). vm_fault also now uses the new VM page counter inlines. This completes the changeover from vnode->v_lastr to vm_entry_t->v_lastr for VM, and fp->f_nextread and fp->f_seqcount (which have been in the tree for a while). Determination of the I/O strategy (sequential, random, and so forth) is now handled on a descriptor-by-descriptor basis for base I/O calls, and on a memory-region-by-memory-region and process-by-process basis for VM faults. Reviewed by: David Greenman , Alan Cox

$Id$ -> $FreeBSD$

1999-08-28T01:08:13Z

Move the memory access behavior information provided by madvise

1999-08-01T06:05:09Z

from the vm_object to the vm_map. Submitted by: dillon

Convert a "page not busy" warning to an assertion.

1999-07-20T05:46:56Z

Submitted by: dillon@backplane.com

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

1999-05-02T23:57:16Z

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

Reviewed by: Matthew Dillon

1999-02-25T06:00:52Z

Corrected the computation of cnt.v_ozfod in vm_fault: vm_fault was counting the number of unoptimized rather than optimized zero-fill faults.

Submitted by: Luoqi Chen

1999-02-17T09:08:29Z

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.