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6d3a2e129f
NetBSD/sys/uvm/uvm_bio.c
chs 64c6d1d2dc 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.
2001-09-15 20:36:31 +00:00

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/* $NetBSD: uvm_bio.c,v 1.18 2001/09/15 20:36:45 chs Exp $ */
/*
* Copyright (c) 1998 Chuck Silvers.
* 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. 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.
*
*/
#include "opt_uvmhist.h"
/*
* uvm_bio.c: buffered i/o vnode mapping cache
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <uvm/uvm.h>
/*
* global data structures
*/
/*
* local functions
*/
int ubc_fault __P((struct uvm_faultinfo *, vaddr_t, struct vm_page **, int,
int, vm_fault_t, vm_prot_t, int));
struct ubc_map *ubc_find_mapping __P((struct uvm_object *, voff_t));
/*
* local data structues
*/
#define UBC_HASH(uobj, offset) \
(((((u_long)(uobj)) >> 8) + (((u_long)(offset)) >> PAGE_SHIFT)) & \
ubc_object.hashmask)
#define UBC_QUEUE(offset) \
(&ubc_object.inactive[(((u_long)(offset)) >> ubc_winshift) & \
(UBC_NQUEUES - 1)])
#define UBC_UMAP_ADDR(u) \
(vaddr_t)(ubc_object.kva + (((u) - ubc_object.umap) << ubc_winshift))
#define UMAP_PAGES_LOCKED 0x0001
#define UMAP_MAPPING_CACHED 0x0002
struct ubc_map
{
struct uvm_object * uobj; /* mapped object */
voff_t offset; /* offset into uobj */
voff_t writeoff; /* overwrite offset */
vsize_t writelen; /* overwrite len */
int refcount; /* refcount on mapping */
int flags; /* extra state */
LIST_ENTRY(ubc_map) hash; /* hash table */
TAILQ_ENTRY(ubc_map) inactive; /* inactive queue */
};
static struct ubc_object
{
struct uvm_object uobj; /* glue for uvm_map() */
char *kva; /* where ubc_object is mapped */
struct ubc_map *umap; /* array of ubc_map's */
LIST_HEAD(, ubc_map) *hash; /* hashtable for cached ubc_map's */
u_long hashmask; /* mask for hashtable */
TAILQ_HEAD(ubc_inactive_head, ubc_map) *inactive;
/* inactive queues for ubc_map's */
} ubc_object;
struct uvm_pagerops ubc_pager =
{
NULL, /* init */
NULL, /* reference */
NULL, /* detach */
ubc_fault, /* fault */
/* ... rest are NULL */
};
int ubc_nwins = UBC_NWINS;
int ubc_winshift = UBC_WINSHIFT;
int ubc_winsize;
#ifdef PMAP_PREFER
int ubc_nqueues;
boolean_t ubc_release_unmap = FALSE;
#define UBC_NQUEUES ubc_nqueues
#define UBC_RELEASE_UNMAP ubc_release_unmap
#else
#define UBC_NQUEUES 1
#define UBC_RELEASE_UNMAP FALSE
#endif
/*
* ubc_init
*
* init pager private data structures.
*/
void
ubc_init(void)
{
struct ubc_map *umap;
vaddr_t va;
int i;
/*
* Make sure ubc_winshift is sane.
*/
if (ubc_winshift < PAGE_SHIFT)
ubc_winshift = PAGE_SHIFT;
/*
* init ubc_object.
* alloc and init ubc_map's.
* init inactive queues.
* alloc and init hashtable.
* map in ubc_object.
*/
simple_lock_init(&ubc_object.uobj.vmobjlock);
ubc_object.uobj.pgops = &ubc_pager;
TAILQ_INIT(&ubc_object.uobj.memq);
ubc_object.uobj.uo_npages = 0;
ubc_object.uobj.uo_refs = UVM_OBJ_KERN;
ubc_object.umap = malloc(ubc_nwins * sizeof(struct ubc_map),
M_TEMP, M_NOWAIT);
if (ubc_object.umap == NULL)
panic("ubc_init: failed to allocate ubc_map");
memset(ubc_object.umap, 0, ubc_nwins * sizeof(struct ubc_map));
if (ubc_winshift < PAGE_SHIFT) {
ubc_winshift = PAGE_SHIFT;
}
va = (vaddr_t)1L;
#ifdef PMAP_PREFER
PMAP_PREFER(0, &va);
ubc_nqueues = va >> ubc_winshift;
if (ubc_nqueues == 0) {
ubc_nqueues = 1;
}
if (ubc_nqueues != 1) {
ubc_release_unmap = TRUE;
}
#endif
ubc_winsize = 1 << ubc_winshift;
ubc_object.inactive = malloc(UBC_NQUEUES *
sizeof(struct ubc_inactive_head), M_TEMP, M_NOWAIT);
if (ubc_object.inactive == NULL)
panic("ubc_init: failed to allocate inactive queue heads");
for (i = 0; i < UBC_NQUEUES; i++) {
TAILQ_INIT(&ubc_object.inactive[i]);
}
for (i = 0; i < ubc_nwins; i++) {
umap = &ubc_object.umap[i];
TAILQ_INSERT_TAIL(&ubc_object.inactive[i & (UBC_NQUEUES - 1)],
umap, inactive);
}
ubc_object.hash = hashinit(ubc_nwins, HASH_LIST, M_TEMP, M_NOWAIT,
&ubc_object.hashmask);
for (i = 0; i <= ubc_object.hashmask; i++) {
LIST_INIT(&ubc_object.hash[i]);
}
if (uvm_map(kernel_map, (vaddr_t *)&ubc_object.kva,
ubc_nwins << ubc_winshift, &ubc_object.uobj, 0, (vsize_t)va,
UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
UVM_ADV_RANDOM, UVM_FLAG_NOMERGE)) != 0) {
panic("ubc_init: failed to map ubc_object\n");
}
UVMHIST_INIT(ubchist, 300);
}
/*
* ubc_fault: fault routine for ubc mapping
*/
int
ubc_fault(ufi, ign1, ign2, ign3, ign4, fault_type, access_type, flags)
struct uvm_faultinfo *ufi;
vaddr_t ign1;
struct vm_page **ign2;
int ign3, ign4;
vm_fault_t fault_type;
vm_prot_t access_type;
int flags;
{
struct uvm_object *uobj;
struct vnode *vp;
struct ubc_map *umap;
vaddr_t va, eva, ubc_offset, slot_offset;
int i, error, npages;
struct vm_page *pgs[ubc_winsize >> PAGE_SHIFT], *pg;
UVMHIST_FUNC("ubc_fault"); UVMHIST_CALLED(ubchist);
/*
* no need to try with PGO_LOCKED...
* we don't need to have the map locked since we know that
* no one will mess with it until our reference is released.
*/
if (flags & PGO_LOCKED) {
uvmfault_unlockall(ufi, NULL, &ubc_object.uobj, NULL);
flags &= ~PGO_LOCKED;
}
va = ufi->orig_rvaddr;
ubc_offset = va - (vaddr_t)ubc_object.kva;
UVMHIST_LOG(ubchist, "va 0x%lx ubc_offset 0x%lx at %d",
va, ubc_offset, access_type,0);
umap = &ubc_object.umap[ubc_offset >> ubc_winshift];
KASSERT(umap->refcount != 0);
slot_offset = ubc_offset & (ubc_winsize - 1);
/* no umap locking needed since we have a ref on the umap */
uobj = umap->uobj;
vp = (struct vnode *)uobj;
KASSERT(vp != NULL);
npages = MIN(ubc_winsize - slot_offset,
(int)(round_page(MAX(vp->v_size, umap->offset +
umap->writeoff + umap->writelen)) -
umap->offset)) >> PAGE_SHIFT;
again:
memset(pgs, 0, sizeof (pgs));
simple_lock(&uobj->vmobjlock);
UVMHIST_LOG(ubchist, "slot_offset 0x%x writeoff 0x%x writelen 0x%x "
"v_size 0x%x", slot_offset, umap->writeoff, umap->writelen,
vp->v_size);
UVMHIST_LOG(ubchist, "getpages vp %p offset 0x%x npages %d",
uobj, umap->offset + slot_offset, npages, 0);
flags |= PGO_PASTEOF;
error = VOP_GETPAGES(vp, umap->offset + slot_offset, pgs, &npages, 0,
access_type, 0, flags);
UVMHIST_LOG(ubchist, "getpages error %d npages %d", error, npages,0,0);
if (error == EAGAIN) {
tsleep(&lbolt, PVM, "ubc_fault", 0);
goto again;
}
if (error) {
return error;
}
va = ufi->orig_rvaddr;
eva = ufi->orig_rvaddr + (npages << PAGE_SHIFT);
UVMHIST_LOG(ubchist, "va 0x%lx eva 0x%lx", va, eva, 0,0);
simple_lock(&uobj->vmobjlock);
uvm_lock_pageq();
for (i = 0; va < eva; i++, va += PAGE_SIZE) {
UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i],0,0);
pg = pgs[i];
if (pg == NULL || pg == PGO_DONTCARE) {
continue;
}
if (pg->flags & PG_WANTED) {
wakeup(pg);
}
KASSERT((pg->flags & PG_FAKE) == 0);
if (pg->flags & PG_RELEASED) {
uvm_pagefree(pg);
continue;
}
KASSERT(access_type == VM_PROT_READ ||
(pg->flags & PG_RDONLY) == 0);
pmap_enter(ufi->orig_map->pmap, va, VM_PAGE_TO_PHYS(pg),
VM_PROT_READ | VM_PROT_WRITE, access_type);
uvm_pageactivate(pg);
pg->flags &= ~(PG_BUSY);
UVM_PAGE_OWN(pg, NULL);
}
uvm_unlock_pageq();
simple_unlock(&uobj->vmobjlock);
pmap_update(ufi->orig_map->pmap);
return 0;
}
/*
* local functions
*/
struct ubc_map *
ubc_find_mapping(uobj, offset)
struct uvm_object *uobj;
voff_t offset;
{
struct ubc_map *umap;
LIST_FOREACH(umap, &ubc_object.hash[UBC_HASH(uobj, offset)], hash) {
if (umap->uobj == uobj && umap->offset == offset) {
return umap;
}
}
return NULL;
}
/*
* ubc interface functions
*/
/*
* ubc_alloc: allocate a file mapping window
*/
void *
ubc_alloc(uobj, offset, lenp, flags)
struct uvm_object *uobj;
voff_t offset;
vsize_t *lenp;
int flags;
{
struct vnode *vp = (struct vnode *)uobj;
vaddr_t slot_offset, va;
struct ubc_map *umap;
voff_t umap_offset;
int error;
UVMHIST_FUNC("ubc_alloc"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "uobj %p offset 0x%lx len 0x%lx filesize 0x%x",
uobj, offset, *lenp, vp->v_size);
umap_offset = (offset & ~((voff_t)ubc_winsize - 1));
slot_offset = (vaddr_t)(offset & ((voff_t)ubc_winsize - 1));
*lenp = MIN(*lenp, ubc_winsize - slot_offset);
/*
* the vnode is always locked here, so we don't need to add a ref.
*/
again:
simple_lock(&ubc_object.uobj.vmobjlock);
umap = ubc_find_mapping(uobj, umap_offset);
if (umap == NULL) {
umap = TAILQ_FIRST(UBC_QUEUE(offset));
if (umap == NULL) {
simple_unlock(&ubc_object.uobj.vmobjlock);
tsleep(&lbolt, PVM, "ubc_alloc", 0);
goto again;
}
/*
* remove from old hash (if any), add to new hash.
*/
if (umap->uobj != NULL) {
LIST_REMOVE(umap, hash);
}
umap->uobj = uobj;
umap->offset = umap_offset;
LIST_INSERT_HEAD(&ubc_object.hash[UBC_HASH(uobj, umap_offset)],
umap, hash);
va = UBC_UMAP_ADDR(umap);
if (umap->flags & UMAP_MAPPING_CACHED) {
umap->flags &= ~UMAP_MAPPING_CACHED;
pmap_remove(pmap_kernel(), va, va + ubc_winsize);
pmap_update(pmap_kernel());
}
} else {
va = UBC_UMAP_ADDR(umap);
}
if (umap->refcount == 0) {
TAILQ_REMOVE(UBC_QUEUE(offset), umap, inactive);
}
#ifdef DIAGNOSTIC
if ((flags & UBC_WRITE) && (umap->writeoff || umap->writelen)) {
panic("ubc_fault: concurrent writes vp %p", uobj);
}
#endif
if (flags & UBC_WRITE) {
umap->writeoff = slot_offset;
umap->writelen = *lenp;
}
umap->refcount++;
simple_unlock(&ubc_object.uobj.vmobjlock);
UVMHIST_LOG(ubchist, "umap %p refs %d va %p flags 0x%x",
umap, umap->refcount, va, flags);
if (flags & UBC_FAULTBUSY) {
int npages = (*lenp + PAGE_SIZE - 1) >> PAGE_SHIFT;
struct vm_page *pgs[npages];
int gpflags = PGO_SYNCIO|PGO_OVERWRITE|PGO_PASTEOF;
int i;
if (umap->flags & UMAP_MAPPING_CACHED) {
umap->flags &= ~UMAP_MAPPING_CACHED;
pmap_remove(pmap_kernel(), va, va + ubc_winsize);
}
simple_lock(&uobj->vmobjlock);
error = VOP_GETPAGES(vp, trunc_page(offset), pgs, &npages, 0,
VM_PROT_READ|VM_PROT_WRITE, 0, gpflags);
UVMHIST_LOG(ubchist, "faultbusy getpages %d", error,0,0,0);
if (error) {
goto out;
}
for (i = 0; i < npages; i++) {
pmap_kenter_pa(va + slot_offset + (i << PAGE_SHIFT),
VM_PAGE_TO_PHYS(pgs[i]),
VM_PROT_READ | VM_PROT_WRITE);
}
pmap_update(pmap_kernel());
umap->flags |= UMAP_PAGES_LOCKED;
}
out:
return (void *)(va + slot_offset);
}
/*
* ubc_release: free a file mapping window.
*/
void
ubc_release(va, flags)
void *va;
int flags;
{
struct ubc_map *umap;
struct uvm_object *uobj;
vaddr_t umapva;
boolean_t unmapped;
UVMHIST_FUNC("ubc_release"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "va %p", va,0,0,0);
umap = &ubc_object.umap[((char *)va - ubc_object.kva) >> ubc_winshift];
umapva = UBC_UMAP_ADDR(umap);
uobj = umap->uobj;
KASSERT(uobj != NULL);
if (umap->flags & UMAP_PAGES_LOCKED) {
int slot_offset = umap->writeoff;
int endoff = umap->writeoff + umap->writelen;
int zerolen = round_page(endoff) - endoff;
int npages = (int)(round_page(umap->writeoff + umap->writelen)
- trunc_page(umap->writeoff)) >> PAGE_SHIFT;
struct vm_page *pgs[npages];
paddr_t pa;
int i;
boolean_t rv;
if (zerolen) {
memset((char *)umapva + endoff, 0, zerolen);
}
umap->flags &= ~UMAP_PAGES_LOCKED;
uvm_lock_pageq();
for (i = 0; i < npages; i++) {
rv = pmap_extract(pmap_kernel(),
umapva + slot_offset + (i << PAGE_SHIFT), &pa);
KASSERT(rv);
pgs[i] = PHYS_TO_VM_PAGE(pa);
pgs[i]->flags &= ~(PG_FAKE|PG_CLEAN);
uvm_pageactivate(pgs[i]);
}
uvm_unlock_pageq();
pmap_kremove(umapva, ubc_winsize);
pmap_update(pmap_kernel());
uvm_page_unbusy(pgs, npages);
unmapped = TRUE;
} else {
unmapped = FALSE;
}
simple_lock(&ubc_object.uobj.vmobjlock);
umap->writeoff = 0;
umap->writelen = 0;
umap->refcount--;
if (umap->refcount == 0) {
if (UBC_RELEASE_UNMAP &&
(((struct vnode *)uobj)->v_flag & VTEXT)) {
/*
* if this file is the executable image of
* some process, that process will likely have
* the file mapped at an alignment other than
* what PMAP_PREFER() would like. we'd like
* to have process text be able to use the
* cache even if someone is also reading the
* file, so invalidate mappings of such files
* as soon as possible.
*/
pmap_remove(pmap_kernel(), umapva,
umapva + ubc_winsize);
umap->flags &= ~UMAP_MAPPING_CACHED;
pmap_update(pmap_kernel());
LIST_REMOVE(umap, hash);
umap->uobj = NULL;
TAILQ_INSERT_HEAD(UBC_QUEUE(umap->offset), umap,
inactive);
} else {
if (!unmapped) {
umap->flags |= UMAP_MAPPING_CACHED;
}
TAILQ_INSERT_TAIL(UBC_QUEUE(umap->offset), umap,
inactive);
}
}
UVMHIST_LOG(ubchist, "umap %p refs %d", umap, umap->refcount,0,0);
simple_unlock(&ubc_object.uobj.vmobjlock);
}
/*
* removing a range of mappings from the ubc mapping cache.
*/
void
ubc_flush(uobj, start, end)
struct uvm_object *uobj;
voff_t start, end;
{
struct ubc_map *umap;
vaddr_t va;
UVMHIST_FUNC("ubc_flush"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "uobj %p start 0x%lx end 0x%lx",
uobj, start, end,0);
simple_lock(&ubc_object.uobj.vmobjlock);
for (umap = ubc_object.umap;
umap < &ubc_object.umap[ubc_nwins];
umap++) {
if (umap->uobj != uobj || umap->offset < start ||
(umap->offset >= end && end != 0) ||
umap->refcount > 0) {
continue;
}
/*
* remove from hash,
* move to head of inactive queue.
*/
va = (vaddr_t)(ubc_object.kva +
((umap - ubc_object.umap) << ubc_winshift));
pmap_remove(pmap_kernel(), va, va + ubc_winsize);
LIST_REMOVE(umap, hash);
umap->uobj = NULL;
TAILQ_REMOVE(UBC_QUEUE(umap->offset), umap, inactive);
TAILQ_INSERT_HEAD(UBC_QUEUE(umap->offset), umap, inactive);
}
pmap_update(pmap_kernel());
simple_unlock(&ubc_object.uobj.vmobjlock);
}
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