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freebsd-skq/sys/vm/vnode_pager.h

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/* -> /*- for license, minor formatting changes
2005-01-07 02:29:27 +00:00
/*-
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vnode_pager.h 8.1 (Berkeley) 6/11/93
$Id$ -> $FreeBSD$
1999-08-28 01:08:13 +00:00
* $FreeBSD$
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
#ifndef _VNODE_PAGER_
#define _VNODE_PAGER_ 1
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.
1999-12-29 05:07:58 +00:00
#ifdef _KERNEL
In the author's words: These diffs implement the first stage of a VOP_{GET|PUT}PAGES pushdown for local media FS's. See ffs_putpages in /sys/ufs/ufs/ufs_readwrite.c for implementation details for generic *_{get|put}pages for local media FS's. Support is trivial to add for any FS that formerly relied on the default behaviour of the vnode_pager in in EOPNOTSUPP cases (just copy the ffs_getpages() code for the FS in question's *_{get|put}pages). Obviously, it would be better if each local media FS implemented a more optimal method, instead of calling an exported interface from the /sys/vm/vnode_pager.c, but this is a necessary first step in getting the FS's to a point where they can be supplied with better implementations on a case-by-case basis. Obviously, the cd9660_putpages() can be rather trivial (since it is a read-only FS type 8-)). A slight (temporary) modification is made to print a diagnostic message in the case where the underlying filesystem attempts to engage in the previous behaviour. Failure is likely to be ungraceful. Submitted by: terry@freebsd.org (Terry Lambert)
1998-02-26 06:39:59 +00:00
Remove __P.
2002-03-19 22:20:14 +00:00
int vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m,
int count, int reqpage);
int vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m,
In the author's words: These diffs implement the first stage of a VOP_{GET|PUT}PAGES pushdown for local media FS's. See ffs_putpages in /sys/ufs/ufs/ufs_readwrite.c for implementation details for generic *_{get|put}pages for local media FS's. Support is trivial to add for any FS that formerly relied on the default behaviour of the vnode_pager in in EOPNOTSUPP cases (just copy the ffs_getpages() code for the FS in question's *_{get|put}pages). Obviously, it would be better if each local media FS implemented a more optimal method, instead of calling an exported interface from the /sys/vm/vnode_pager.c, but this is a necessary first step in getting the FS's to a point where they can be supplied with better implementations on a case-by-case basis. Obviously, the cd9660_putpages() can be rather trivial (since it is a read-only FS type 8-)). A slight (temporary) modification is made to print a diagnostic message in the case where the underlying filesystem attempts to engage in the previous behaviour. Failure is likely to be ungraceful. Submitted by: terry@freebsd.org (Terry Lambert)
1998-02-26 06:39:59 +00:00
int count, boolean_t sync,
Remove __P.
2002-03-19 22:20:14 +00:00
int *rtvals);
In the VOP_PUTPAGES() implementations, change the default error from VM_PAGER_AGAIN to VM_PAGER_ERROR for the uwritten pages. Return VM_PAGER_AGAIN for the partially written page. Always forward at least one page in the loop of vm_object_page_clean(). VM_PAGER_ERROR causes the page reactivation and does not clear the page dirty state, so the write is not lost. The change fixes an infinite loop in vm_object_page_clean() when the filesystem returns permanent errors for some page writes. Reported and tested by: gavin Reviewed by: alc, rmacklem MFC after: 1 week
2011-06-01 21:00:28 +00:00
Account the writeable shared mappings backed by file in the vnode v_writecount. Keep the amount of the virtual address space used by the mappings in the new vm_object un_pager.vnp.writemappings counter. The vnode v_writecount is incremented when writemappings gets non-zero value, and decremented when writemappings is returned to zero. Writeable shared vnode-backed mappings are accounted for in vm_mmap(), and vm_map_insert() is instructed to set MAP_ENTRY_VN_WRITECNT flag on the created map entry. During deferred map entry deallocation, vm_map_process_deferred() checks for MAP_ENTRY_VN_WRITECOUNT and decrements writemappings for the vm object. Now, the writeable mount cannot be demoted to read-only while writeable shared mappings of the vnodes from the mount point exist. Also, execve(2) fails for such files with ETXTBUSY, as it should be. Noted by: tegge Reviewed by: tegge (long time ago, early version), alc Tested by: pho MFC after: 3 weeks
2012-02-23 21:07:16 +00:00
void vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
vm_offset_t end);
In the VOP_PUTPAGES() implementations, change the default error from VM_PAGER_AGAIN to VM_PAGER_ERROR for the uwritten pages. Return VM_PAGER_AGAIN for the partially written page. Always forward at least one page in the loop of vm_object_page_clean(). VM_PAGER_ERROR causes the page reactivation and does not clear the page dirty state, so the write is not lost. The change fixes an infinite loop in vm_object_page_clean() when the filesystem returns permanent errors for some page writes. Reported and tested by: gavin Reviewed by: alc, rmacklem MFC after: 1 week
2011-06-01 21:00:28 +00:00
void vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written);
Account the writeable shared mappings backed by file in the vnode v_writecount. Keep the amount of the virtual address space used by the mappings in the new vm_object un_pager.vnp.writemappings counter. The vnode v_writecount is incremented when writemappings gets non-zero value, and decremented when writemappings is returned to zero. Writeable shared vnode-backed mappings are accounted for in vm_mmap(), and vm_map_insert() is instructed to set MAP_ENTRY_VN_WRITECNT flag on the created map entry. During deferred map entry deallocation, vm_map_process_deferred() checks for MAP_ENTRY_VN_WRITECOUNT and decrements writemappings for the vm object. Now, the writeable mount cannot be demoted to read-only while writeable shared mappings of the vnodes from the mount point exist. Also, execve(2) fails for such files with ETXTBUSY, as it should be. Noted by: tegge Reviewed by: tegge (long time ago, early version), alc Tested by: pho MFC after: 3 weeks
2012-02-23 21:07:16 +00:00
void vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
vm_offset_t end);
In the VOP_PUTPAGES() implementations, change the default error from VM_PAGER_AGAIN to VM_PAGER_ERROR for the uwritten pages. Return VM_PAGER_AGAIN for the partially written page. Always forward at least one page in the loop of vm_object_page_clean(). VM_PAGER_ERROR causes the page reactivation and does not clear the page dirty state, so the write is not lost. The change fixes an infinite loop in vm_object_page_clean() when the filesystem returns permanent errors for some page writes. Reported and tested by: gavin Reviewed by: alc, rmacklem MFC after: 1 week
2011-06-01 21:00:28 +00:00
- 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
2002-03-10 21:52:48 +00:00
#endif /* _KERNEL */
These changes embody the support of the fully coherent merged VM buffer cache, much higher filesystem I/O performance, and much better paging performance. It represents the culmination of over 6 months of R&D. The majority of the merged VM/cache work is by John Dyson. The following highlights the most significant changes. Additionally, there are (mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to support the new VM/buffer scheme. vfs_bio.c: Significant rewrite of most of vfs_bio to support the merged VM buffer cache scheme. The scheme is almost fully compatible with the old filesystem interface. Significant improvement in the number of opportunities for write clustering. vfs_cluster.c, vfs_subr.c Upgrade and performance enhancements in vfs layer code to support merged VM/buffer cache. Fixup of vfs_cluster to eliminate the bogus pagemove stuff. vm_object.c: Yet more improvements in the collapse code. Elimination of some windows that can cause list corruption. vm_pageout.c: Fixed it, it really works better now. Somehow in 2.0, some "enhancements" broke the code. This code has been reworked from the ground-up. vm_fault.c, vm_page.c, pmap.c, vm_object.c Support for small-block filesystems with merged VM/buffer cache scheme. pmap.c vm_map.c Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of kernel PTs. vm_glue.c Much simpler and more effective swapping code. No more gratuitous swapping. proc.h Fixed the problem that the p_lock flag was not being cleared on a fork. swap_pager.c, vnode_pager.c Removal of old vfs_bio cruft to support the past pseudo-coherency. Now the code doesn't need it anymore. machdep.c Changes to better support the parameter values for the merged VM/buffer cache scheme. machdep.c, kern_exec.c, vm_glue.c Implemented a seperate submap for temporary exec string space and another one to contain process upages. This eliminates all map fragmentation problems that previously existed. ffs_inode.c, ufs_inode.c, ufs_readwrite.c Changes for merged VM/buffer cache. Add "bypass" support for sneaking in on busy buffers. Submitted by: John Dyson and David Greenman
1995-01-09 16:06:02 +00:00
#endif /* _VNODE_PAGER_ */
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