NetBSD/sys/uvm/uvm.h

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a whole bunch of changes to improve performance and robustness under load: - remove special treatment of pager_map mappings in pmaps. this is required now, since I've removed the globals that expose the address range. pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's no longer any need to special-case it. - eliminate struct uvm_vnode by moving its fields into struct vnode. - rewrite the pageout path. the pager is now responsible for handling the high-level requests instead of only getting control after a bunch of work has already been done on its behalf. this will allow us to UBCify LFS, which needs tighter control over its pages than other filesystems do. writing a page to disk no longer requires making it read-only, which allows us to write wired pages without causing all kinds of havoc. - use a new PG_PAGEOUT flag to indicate that a page should be freed on behalf of the pagedaemon when it's unlocked. this flag is very similar to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the pageout fails due to eg. an indirect-block buffer being locked. this allows us to remove the "version" field from struct vm_page, and together with shrinking "loan_count" from 32 bits to 16, struct vm_page is now 4 bytes smaller. - no longer use PG_RELEASED for swap-backed pages. if the page is busy because it's being paged out, we can't release the swap slot to be reallocated until that write is complete, but unlike with vnodes we don't keep a count of in-progress writes so there's no good way to know when the write is done. instead, when we need to free a busy swap-backed page, just sleep until we can get it busy ourselves. - implement a fast-path for extending writes which allows us to avoid zeroing new pages. this substantially reduces cpu usage. - encapsulate the data used by the genfs code in a struct genfs_node, which must be the first element of the filesystem-specific vnode data for filesystems which use genfs_{get,put}pages(). - eliminate many of the UVM pagerops, since they aren't needed anymore now that the pager "put" operation is a higher-level operation. - enhance the genfs code to allow NFS to use the genfs_{get,put}pages instead of a modified copy. - clean up struct vnode by removing all the fields that used to be used by the vfs_cluster.c code (which we don't use anymore with UBC). - remove kmem_object and mb_object since they were useless. instead of allocating pages to these objects, we now just allocate pages with no object. such pages are mapped in the kernel until they are freed, so we can use the mapping to find the page to free it. this allows us to remove splvm() protection in several places. The sum of all these changes improves write throughput on my decstation 5000/200 to within 1% of the rate of NetBSD 1.5 and reduces the elapsed time for "make release" of a NetBSD 1.5 source tree on my 128MB pc to 10% less than a 1.5 kernel took.
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/* $NetBSD: uvm.h,v 1.31 2001/09/15 20:36:44 chs Exp $ */
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/*
*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Charles D. Cranor and
* Washington University.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
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*
* from: Id: uvm.h,v 1.1.2.14 1998/02/02 20:07:19 chuck Exp
*/
#ifndef _UVM_UVM_H_
#define _UVM_UVM_H_
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#if defined(_KERNEL_OPT)
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#include "opt_lockdebug.h"
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#include "opt_multiprocessor.h"
#include "opt_uvmhist.h"
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#endif
#include <uvm/uvm_extern.h>
#include <uvm/uvm_stat.h>
/*
* pull in prototypes
*/
#include <uvm/uvm_amap.h>
#include <uvm/uvm_aobj.h>
#include <uvm/uvm_fault.h>
#include <uvm/uvm_glue.h>
#include <uvm/uvm_km.h>
#include <uvm/uvm_loan.h>
#include <uvm/uvm_map.h>
#include <uvm/uvm_object.h>
#include <uvm/uvm_page.h>
#include <uvm/uvm_pager.h>
#include <uvm/uvm_pdaemon.h>
#include <uvm/uvm_swap.h>
/*
* pull in VM_NFREELIST
*/
#include <machine/vmparam.h>
/*
* uvm structure (vm global state: collected in one structure for ease
* of reference...)
*/
struct uvm {
/* vm_page related parameters */
/* vm_page queues */
struct pgfreelist page_free[VM_NFREELIST]; /* unallocated pages */
int page_free_nextcolor; /* next color to allocate from */
struct pglist page_active; /* allocated pages, in use */
struct pglist page_inactive; /* pages between the clock hands */
struct simplelock pageqlock; /* lock for active/inactive page q */
struct simplelock fpageqlock; /* lock for free page q */
boolean_t page_init_done; /* TRUE if uvm_page_init() finished */
boolean_t page_idle_zero; /* TRUE if we should try to zero
pages in the idle loop */
/* page daemon trigger */
int pagedaemon; /* daemon sleeps on this */
struct proc *pagedaemon_proc; /* daemon's pid */
struct simplelock pagedaemon_lock;
/* aiodone daemon trigger */
int aiodoned; /* daemon sleeps on this */
struct proc *aiodoned_proc; /* daemon's pid */
struct simplelock aiodoned_lock;
/* page hash */
struct pglist *page_hash; /* page hash table (vp/off->page) */
int page_nhash; /* number of buckets */
int page_hashmask; /* hash mask */
struct simplelock hashlock; /* lock on page_hash array */
/* anon stuff */
struct vm_anon *afree; /* anon free list */
struct simplelock afreelock; /* lock on anon free list */
/* static kernel map entry pool */
struct vm_map_entry *kentry_free; /* free page pool */
struct simplelock kentry_lock;
/* aio_done is locked by uvm.pagedaemon_lock and splbio! */
TAILQ_HEAD(, buf) aio_done; /* done async i/o reqs */
/* swap-related items */
struct simplelock swap_data_lock;
/* kernel object: to support anonymous pageable kernel memory */
struct uvm_object *kernel_object;
};
/*
* vm_map_entry etype bits:
*/
#define UVM_ET_OBJ 0x01 /* it is a uvm_object */
#define UVM_ET_SUBMAP 0x02 /* it is a vm_map submap */
#define UVM_ET_COPYONWRITE 0x04 /* copy_on_write */
#define UVM_ET_NEEDSCOPY 0x08 /* needs_copy */
#define UVM_ET_ISOBJ(E) (((E)->etype & UVM_ET_OBJ) != 0)
#define UVM_ET_ISSUBMAP(E) (((E)->etype & UVM_ET_SUBMAP) != 0)
#define UVM_ET_ISCOPYONWRITE(E) (((E)->etype & UVM_ET_COPYONWRITE) != 0)
#define UVM_ET_ISNEEDSCOPY(E) (((E)->etype & UVM_ET_NEEDSCOPY) != 0)
#ifdef _KERNEL
/*
* holds all the internal UVM data
*/
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extern struct uvm uvm;
/*
* historys
*/
UVMHIST_DECL(maphist);
UVMHIST_DECL(pdhist);
UVMHIST_DECL(ubchist);
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/*
* UVM_UNLOCK_AND_WAIT: atomic unlock+wait... wrapper around the
* interlocked tsleep() function.
*/
#define UVM_UNLOCK_AND_WAIT(event, slock, intr, msg, timo) \
do { \
(void) ltsleep(event, PVM | PNORELOCK | (intr ? PCATCH : 0), \
msg, timo, slock); \
} while (0)
/*
* UVM_KICK_PDAEMON: perform checks to determine if we need to
* give the pagedaemon a nudge, and do so if necessary.
*/
#define UVM_KICK_PDAEMON() \
do { \
if (uvmexp.free + uvmexp.paging < uvmexp.freemin || \
(uvmexp.free + uvmexp.paging < uvmexp.freetarg && \
uvmexp.inactive < uvmexp.inactarg)) { \
wakeup(&uvm.pagedaemon); \
} \
} while (/*CONSTCOND*/0)
/*
* UVM_PAGE_OWN: track page ownership (only if UVM_PAGE_TRKOWN)
*/
#if defined(UVM_PAGE_TRKOWN)
#define UVM_PAGE_OWN(PG, TAG) uvm_page_own(PG, TAG)
#else
#define UVM_PAGE_OWN(PG, TAG) /* nothing */
#endif /* UVM_PAGE_TRKOWN */
/*
* pull in inlines
*/
#include <uvm/uvm_amap_i.h>
#include <uvm/uvm_fault_i.h>
#include <uvm/uvm_map_i.h>
#include <uvm/uvm_page_i.h>
#include <uvm/uvm_pager_i.h>
#endif /* _KERNEL */
#endif /* _UVM_UVM_H_ */