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-rw-r--r--sys/vm/vnode_pager.c599
1 files changed, 528 insertions, 71 deletions
diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c
index 41c2872e4d39..c35971ba67e0 100644
--- a/sys/vm/vnode_pager.c
+++ b/sys/vm/vnode_pager.c
@@ -2,6 +2,7 @@
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
+ * Copyright (c) 1993 John S. Dyson
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
@@ -36,7 +37,7 @@
* SUCH DAMAGE.
*
* from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
- * $Id: vnode_pager.c,v 1.2 1993/10/16 16:21:02 rgrimes Exp $
+ * $Id: vnode_pager.c,v 1.11.2.3 1994/04/18 04:57:49 rgrimes Exp $
*/
/*
@@ -46,8 +47,24 @@
* pageouts
* fix credential use (uses current process credentials now)
*/
-#include "vnodepager.h"
-#if NVNODEPAGER > 0
+
+/*
+ * MODIFICATIONS:
+ * John S. Dyson 08 Dec 93
+ *
+ * This file in conjunction with some vm_fault mods, eliminate the performance
+ * advantage for using the buffer cache and minimize memory copies.
+ *
+ * 1) Supports multiple - block reads
+ * 2) Bypasses buffer cache for reads
+ *
+ * TODO:
+ *
+ * 1) Totally bypass buffer cache for reads
+ * (Currently will still sometimes use buffer cache for reads)
+ * 2) Bypass buffer cache for writes
+ * (Code does not support it, but mods are simple)
+ */
#include "param.h"
#include "proc.h"
@@ -57,12 +74,34 @@
#include "mount.h"
#include "vm_param.h"
+#include "vm.h"
#include "lock.h"
#include "queue.h"
#include "vm_prot.h"
#include "vm_object.h"
#include "vm_page.h"
#include "vnode_pager.h"
+#include "vm_map.h"
+#include "vm_pageout.h"
+#include "buf.h"
+#include "specdev.h"
+
+struct pagerops vnodepagerops = {
+ vnode_pager_init,
+ vnode_pager_alloc,
+ vnode_pager_dealloc,
+ vnode_pager_getpage,
+ vnode_pager_getmulti,
+ vnode_pager_putpage,
+ vnode_pager_haspage
+};
+
+static int vnode_pager_io(vn_pager_t vnp, vm_page_t *m, int count, int reqpage,
+ enum uio_rw rw);
+struct buf * getpbuf() ;
+void relpbuf(struct buf *bp) ;
+
+extern vm_map_t pager_map;
queue_head_t vnode_pager_list; /* list of managed vnodes */
@@ -91,10 +130,11 @@ vnode_pager_init()
* Handle is a vnode pointer.
*/
vm_pager_t
-vnode_pager_alloc(handle, size, prot)
+vnode_pager_alloc(handle, size, prot, offset)
caddr_t handle;
vm_size_t size;
vm_prot_t prot;
+ vm_offset_t offset;
{
register vm_pager_t pager;
register vn_pager_t vnp;
@@ -200,17 +240,37 @@ vnode_pager_dealloc(pager)
free((caddr_t)pager, M_VMPAGER);
}
+int
+vnode_pager_getmulti(pager, m, count, reqpage, sync)
+ vm_pager_t pager;
+ vm_page_t *m;
+ int count;
+ int reqpage;
+ boolean_t sync;
+{
+
+ return vnode_pager_io((vn_pager_t) pager->pg_data, m, count, reqpage, UIO_READ);
+}
+
+
+int
vnode_pager_getpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
+ int err;
+ vm_page_t marray[1];
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_getpage(%x, %x)\n", pager, m);
#endif
- return(vnode_pager_io((vn_pager_t)pager->pg_data, m, UIO_READ));
+ if (pager == NULL)
+ return FALSE;
+ marray[0] = m;
+
+ return vnode_pager_io((vn_pager_t)pager->pg_data, marray, 1, 0, UIO_READ);
}
boolean_t
@@ -220,19 +280,17 @@ vnode_pager_putpage(pager, m, sync)
boolean_t sync;
{
int err;
+ vm_page_t marray[1];
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_putpage(%x, %x)\n", pager, m);
#endif
if (pager == NULL)
- return;
- err = vnode_pager_io((vn_pager_t)pager->pg_data, m, UIO_WRITE);
- if (err == VM_PAGER_OK) {
- m->clean = TRUE; /* XXX - wrong place */
- pmap_clear_modify(VM_PAGE_TO_PHYS(m)); /* XXX - wrong place */
- }
- return(err);
+ return FALSE;
+ marray[0] = m;
+ err = vnode_pager_io((vn_pager_t)pager->pg_data, marray, 1, 0, UIO_WRITE);
+ return err;
}
boolean_t
@@ -292,6 +350,7 @@ vnode_pager_haspage(pager, offset)
* Note: this routine may be invoked as a result of a pager put
* operation (possibly at object termination time), so we must be careful.
*/
+void
vnode_pager_setsize(vp, nsize)
struct vnode *vp;
u_long nsize;
@@ -329,20 +388,22 @@ vnode_pager_setsize(vp, nsize)
printf("vnode_pager_setsize: vp %x obj %x osz %d nsz %d\n",
vp, object, vnp->vnp_size, nsize);
#endif
+
/*
* File has shrunk.
* Toss any cached pages beyond the new EOF.
*/
- if (nsize < vnp->vnp_size) {
+ if (round_page(nsize) < round_page(vnp->vnp_size)) {
vm_object_lock(object);
vm_object_page_remove(object,
- (vm_offset_t)nsize, vnp->vnp_size);
+ (vm_offset_t)round_page(nsize), round_page(vnp->vnp_size));
vm_object_unlock(object);
}
vnp->vnp_size = (vm_offset_t)nsize;
vm_object_deallocate(object);
}
+void
vnode_pager_umount(mp)
register struct mount *mp;
{
@@ -407,78 +468,474 @@ vnode_pager_uncache(vp)
return(uncached);
}
-vnode_pager_io(vnp, m, rw)
- register vn_pager_t vnp;
+
+void
+vnode_pager_freepage(m)
vm_page_t m;
+{
+ PAGE_WAKEUP(m);
+ vm_page_free(m);
+}
+
+/*
+ * calculate the linear (byte) disk address of specified virtual
+ * file address
+ */
+vm_offset_t
+vnode_pager_addr(vp, address)
+ struct vnode *vp;
+ vm_offset_t address;
+{
+ int rtaddress;
+ int bsize;
+ vm_offset_t block;
+ struct vnode *rtvp;
+ int err;
+ int vblock, voffset;
+
+ bsize = vp->v_mount->mnt_stat.f_bsize;
+ vblock = address / bsize;
+ voffset = address % bsize;
+
+ err = VOP_BMAP(vp,vblock,&rtvp,&block);
+
+ rtaddress = block * DEV_BSIZE + voffset;
+
+ return rtaddress;
+}
+
+/*
+ * interrupt routine for I/O completion
+ */
+void
+vnode_pager_iodone(bp)
+ struct buf *bp;
+{
+ bp->b_flags |= B_DONE;
+ wakeup((caddr_t)bp);
+}
+
+/*
+ * vnode_pager_io:
+ * Perform read or write operation for vnode_paging
+ *
+ * args:
+ * vnp -- pointer to vnode pager data structure
+ * containing size and vnode pointer, etc
+ *
+ * m -- pointer to array of vm_page_t entries to
+ * do I/O to. It is not necessary to fill any
+ * pages except for the reqpage entry. If a
+ * page is not filled, it needs to be removed
+ * from its object...
+ *
+ * count -- number of pages for I/O
+ *
+ * reqpage -- fault requested page for I/O
+ * (index into vm_page_t entries above)
+ *
+ * rw -- UIO_READ or UIO_WRITE
+ *
+ * NOTICE!!!! direct writes look like that they are close to being
+ * implemented. They are not really, several things need
+ * to be done to make it work (subtile things.) Hack at
+ * your own risk (direct writes are scarey).
+ *
+ * ANOTHER NOTICE!!!!
+ * we currently only support direct I/O to filesystems whose
+ * contiguously allocated blocksize is at least a vm page.
+ * changes will be made in the future to support more flexibility.
+ */
+
+int
+vnode_pager_io(vnp, m, count, reqpage, rw)
+ register vn_pager_t vnp;
+ vm_page_t *m;
+ int count, reqpage;
enum uio_rw rw;
{
+ int i,j;
struct uio auio;
struct iovec aiov;
vm_offset_t kva, foff;
- int error, size;
+ int size;
struct proc *p = curproc; /* XXX */
+ vm_object_t object;
+ vm_offset_t paging_offset;
+ struct vnode *dp, *vp;
+ vm_offset_t mapsize;
+ int bsize;
+ int errtype=0; /* 0 is file type otherwise vm type */
+ int error = 0;
+ int trimmed;
-#ifdef DEBUG
- if (vpagerdebug & VDB_FOLLOW)
- printf("vnode_pager_io(%x, %x, %c): vnode %x\n",
- vnp, m, rw == UIO_READ ? 'R' : 'W', vnp->vnp_vp);
-#endif
- foff = m->offset + m->object->paging_offset;
+ object = m[reqpage]->object; /* all vm_page_t items are in same object */
+ paging_offset = object->paging_offset;
+
+ vp = vnp->vnp_vp;
+ bsize = vp->v_mount->mnt_stat.f_bsize;
+
+ /* get the UNDERLYING device for the file with VOP_BMAP() */
/*
- * Return failure if beyond current EOF
+ * originally, we did not check for an error return
+ * value -- assuming an fs always has a bmap entry point
+ * -- that assumption is wrong!!!
*/
- if (foff >= vnp->vnp_size) {
-#ifdef DEBUG
- if (vpagerdebug & VDB_SIZE)
- printf("vnode_pager_io: vp %x, off %d size %d\n",
- vnp->vnp_vp, foff, vnp->vnp_size);
-#endif
- return(VM_PAGER_BAD);
+ /*
+ * we only do direct I/O if the file is on a local
+ * BLOCK device and currently if it is a read operation only.
+ */
+ kva = 0;
+ mapsize = 0;
+ if (!VOP_BMAP(vp, m[reqpage]->offset+paging_offset, &dp, 0) &&
+ rw == UIO_READ && ((dp->v_type == VBLK &&
+ (vp->v_mount->mnt_stat.f_type == MOUNT_UFS)) ||
+ (vp->v_mount->mnt_stat.f_type == MOUNT_NFS))) {
+ /*
+ * we do not block for a kva, notice we default to a kva
+ * conservative behavior
+ */
+ kva = kmem_alloc_pageable(pager_map,
+ (mapsize = count*NBPG));
+ if( !kva) {
+ for (i = 0; i < count; i++) {
+ if (i != reqpage) {
+ vnode_pager_freepage(m[i]);
+ m[i] = 0;
+ }
+ }
+ m[0] = m[reqpage];
+ kva = vm_pager_map_page(m[0]);
+ reqpage = 0;
+ count = 1;
+ mapsize = count*NBPG;
+ }
}
- if (foff + PAGE_SIZE > vnp->vnp_size)
- size = vnp->vnp_size - foff;
- else
- size = PAGE_SIZE;
+
+ if (!kva) {
+ /*
+ * here on I/O through VFS
+ */
+ for (i = 0; i < count; i++) {
+ if (i != reqpage) {
+ vnode_pager_freepage(m[i]);
+ m[i] = 0;
+ }
+ }
+ m[0] = m[reqpage];
+ foff = m[0]->offset + paging_offset;
+ reqpage = 0;
+ count = 1;
/*
- * Allocate a kernel virtual address and initialize so that
- * we can use VOP_READ/WRITE routines.
+ * Return failure if beyond current EOF
*/
- kva = vm_pager_map_page(m);
- aiov.iov_base = (caddr_t)kva;
- aiov.iov_len = size;
- auio.uio_iov = &aiov;
- auio.uio_iovcnt = 1;
- auio.uio_offset = foff;
- auio.uio_segflg = UIO_SYSSPACE;
- auio.uio_rw = rw;
- auio.uio_resid = size;
- auio.uio_procp = (struct proc *)0;
-#ifdef DEBUG
- if (vpagerdebug & VDB_IO)
- printf("vnode_pager_io: vp %x kva %x foff %x size %x",
- vnp->vnp_vp, kva, foff, size);
-#endif
- if (rw == UIO_READ)
- error = VOP_READ(vnp->vnp_vp, &auio, 0, p->p_ucred);
- else
- error = VOP_WRITE(vnp->vnp_vp, &auio, 0, p->p_ucred);
-#ifdef DEBUG
- if (vpagerdebug & VDB_IO) {
- if (error || auio.uio_resid)
- printf(" returns error %x, resid %x",
- error, auio.uio_resid);
- printf("\n");
+ if (foff >= vnp->vnp_size) {
+ errtype = 1;
+ error = VM_PAGER_BAD;
+ } else {
+ if (foff + NBPG > vnp->vnp_size)
+ size = vnp->vnp_size - foff;
+ else
+ size = NBPG;
+/*
+ * Allocate a kernel virtual address and initialize so that
+ * we can use VOP_READ/WRITE routines.
+ */
+ kva = vm_pager_map_page(m[0]);
+ aiov.iov_base = (caddr_t)kva;
+ aiov.iov_len = size;
+ auio.uio_iov = &aiov;
+ auio.uio_iovcnt = 1;
+ auio.uio_offset = foff;
+ auio.uio_segflg = UIO_SYSSPACE;
+ auio.uio_rw = rw;
+ auio.uio_resid = size;
+ auio.uio_procp = (struct proc *)0;
+ if (rw == UIO_READ) {
+ error = VOP_READ(vp, &auio, IO_PAGER, p->p_ucred);
+ } else {
+ error = VOP_WRITE(vp, &auio, IO_PAGER, p->p_ucred);
+ }
+ if (!error) {
+ register int count = size - auio.uio_resid;
+
+ if (count == 0)
+ error = EINVAL;
+ else if (count != NBPG && rw == UIO_READ)
+ bzero((caddr_t)kva + count, NBPG - count);
+ }
+ vm_pager_unmap_page(kva);
+ }
+ } else {
+
+ /*
+ * here on direct device I/O
+ */
+ int first=0, last=count;
+ int reqaddr, firstaddr;
+ int block, offset;
+
+ struct buf *bp;
+ int s;
+ int failflag;
+
+ foff = m[reqpage]->offset + paging_offset;
+
+ /*
+ * This pathetic hack gets data from the buffer cache, if it's there.
+ * I believe that this is not really necessary, and the ends can
+ * be gotten by defaulting to the normal vfs read behavior, but this
+ * might be more efficient, because the will NOT invoke read-aheads
+ * and one of the purposes of this code is to bypass the buffer
+ * cache and keep from flushing it by reading in a program.
+ */
+ /*
+ * calculate logical block and offset
+ */
+ block = foff / bsize;
+ offset = foff % bsize;
+ s = splbio();
+
+ /*
+ * if we have a buffer in core, then try to use it
+ */
+ while (bp = incore(vp, block)) {
+ int amount;
+
+ /*
+ * wait until the buffer is avail or gone
+ */
+ if (bp->b_flags & B_BUSY) {
+ bp->b_flags |= B_WANTED;
+ tsleep ((caddr_t)bp, PVM, "vnwblk", 0);
+ continue;
+ }
+
+ amount = NBPG;
+ if ((foff + amount) > vnp->vnp_size)
+ amount = vnp->vnp_size - foff;
+
+ /*
+ * make sure that this page is in the buffer
+ */
+ if ((amount > 0) && (offset + amount) <= bp->b_bcount) {
+ bp->b_flags |= B_BUSY;
+ splx(s);
+
+ /*
+ * map the requested page
+ */
+ pmap_enter(vm_map_pmap(pager_map),
+ kva, VM_PAGE_TO_PHYS(m[reqpage]),
+ VM_PROT_DEFAULT, TRUE);
+ /*
+ * copy the data from the buffer
+ */
+ bcopy(bp->b_un.b_addr + offset, (caddr_t)kva, amount);
+ if (amount < NBPG) {
+ bzero((caddr_t)kva + amount, NBPG - amount);
+ }
+ /*
+ * unmap the page and free the kva
+ */
+ pmap_remove(vm_map_pmap(pager_map), kva, kva + NBPG);
+ kmem_free_wakeup(pager_map, kva, mapsize);
+ /*
+ * release the buffer back to the block subsystem
+ */
+ bp->b_flags &= ~B_BUSY;
+ wakeup((caddr_t)bp);
+ /*
+ * we did not have to do any work to get the requested
+ * page, the read behind/ahead does not justify a read
+ */
+ for (i = 0; i < count; i++) {
+ if (i != reqpage) {
+ vnode_pager_freepage(m[i]);
+ m[i] = 0;
+ }
+ }
+ /*
+ * sorry for the goto
+ */
+ goto finishup;
+ }
+ /*
+ * buffer is nowhere to be found, read from the disk
+ */
+ break;
+ }
+
+ foff = m[reqpage]->offset + paging_offset;
+ reqaddr = vnode_pager_addr(vp, foff);
+ /*
+ * Make sure that our I/O request is contiguous.
+ * Scan backward and stop for the first discontiguous
+ * entry or stop for a page being in buffer cache.
+ */
+ failflag = 0;
+ for (i = reqpage - 1; i >= 0; --i) {
+ int myaddr;
+ if (failflag ||
+ incore(vp, (foff + (i - reqpage) * NBPG) / bsize) ||
+ (myaddr = vnode_pager_addr(vp, m[i]->offset + paging_offset))
+ != reqaddr + (i - reqpage) * NBPG) {
+ vnode_pager_freepage(m[i]);
+ m[i] = 0;
+ if (first == 0)
+ first = i + 1;
+ failflag = 1;
+ }
+ }
+
+ /*
+ * Scan forward and stop for the first non-contiguous
+ * entry or stop for a page being in buffer cache.
+ */
+ failflag = 0;
+ for (i = reqpage + 1; i < count; i++) {
+ int myaddr;
+ if (failflag ||
+ incore(vp, (foff + (i - reqpage) * NBPG) / bsize) ||
+ (myaddr = vnode_pager_addr(vp, m[i]->offset + paging_offset))
+ != reqaddr + (i - reqpage) * NBPG) {
+ vnode_pager_freepage(m[i]);
+ m[i] = 0;
+ if (last == count)
+ last = i;
+ failflag = 1;
+ }
+ }
+
+ /*
+ * the first and last page have been calculated now, move input
+ * pages to be zero based...
+ */
+ count = last;
+ if (first != 0) {
+ for (i = first; i < count; i++) {
+ m[i - first] = m[i];
+ }
+ count -= first;
+ reqpage -= first;
+ }
+
+
+ /*
+ * calculate the file virtual address for the transfer
+ */
+ foff = m[0]->offset + paging_offset;
+ /*
+ * and get the disk physical address (in bytes)
+ */
+ firstaddr = vnode_pager_addr(vp, foff);
+
+ /*
+ * calculate the size of the transfer
+ */
+ if ((m[count - 1]->offset + paging_offset) + NBPG > vnp->vnp_size)
+ size = vnp->vnp_size - foff;
+ else
+ size = count * NBPG;
+
+
+ /*
+ * and map the pages to be read into the kva
+ */
+ for (i = 0; i < count; i++)
+ pmap_enter(vm_map_pmap(pager_map),
+ kva + NBPG * i, VM_PAGE_TO_PHYS(m[i]),
+ VM_PROT_DEFAULT, TRUE);
+ VHOLD(vp);
+ bp = getpbuf();
+
+ /* build a minimal buffer header */
+ bzero((caddr_t)bp, sizeof(struct buf));
+ bp->b_flags = B_BUSY | B_READ | B_CALL;
+ bp->b_iodone = vnode_pager_iodone;
+ /* B_PHYS is not set, but it is nice to fill this in */
+ /* bp->b_proc = &proc0; */
+ bp->b_proc = curproc;
+ bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
+ bp->b_un.b_addr = (caddr_t) kva;
+ bp->b_blkno = firstaddr / DEV_BSIZE;
+ bp->b_vp = dp;
+
+ /* Should be a BLOCK or character DEVICE if we get here */
+ bp->b_dev = dp->v_rdev;
+ bp->b_bcount = NBPG * count;
+
+ /* do the input */
+ VOP_STRATEGY(bp);
+
+ /* we definitely need to be at splbio here */
+
+ while ((bp->b_flags & B_DONE) == 0) {
+ tsleep((caddr_t)bp, PVM, "vnread", 0);
+ }
+ splx(s);
+ if ((bp->b_flags & B_ERROR) != 0)
+ error = EIO;
+
+ if (!error) {
+ if (size != count * NBPG)
+ bzero((caddr_t)kva + size, NBPG * count - size);
+ }
+ HOLDRELE(vp);
+
+ pmap_remove(vm_map_pmap(pager_map), kva, kva + NBPG * count);
+ kmem_free_wakeup(pager_map, kva, mapsize);
+
+ /*
+ * free the buffer header back to the swap buffer pool
+ */
+ relpbuf(bp);
+
}
-#endif
- if (!error) {
- register int count = size - auio.uio_resid;
- if (count == 0)
- error = EINVAL;
- else if (count != PAGE_SIZE && rw == UIO_READ)
- bzero(kva + count, PAGE_SIZE - count);
+finishup:
+ if (rw == UIO_READ)
+ for (i = 0; i < count; i++) {
+ /*
+ * we dont mess with pages that have been already
+ * deallocated....
+ */
+ if (!m[i])
+ continue;
+ pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
+ m[i]->flags |= PG_CLEAN;
+ m[i]->flags &= ~PG_LAUNDRY;
+ if (i != reqpage) {
+ /*
+ * whether or not to leave the page activated
+ * is up in the air, but we should put the page
+ * on a page queue somewhere. (it already is in
+ * the object).
+ * Result: It appears that emperical results show
+ * that deactivating pages is best.
+ */
+ /*
+ * just in case someone was asking for this
+ * page we now tell them that it is ok to use
+ */
+ if (!error) {
+ vm_page_deactivate(m[i]);
+ PAGE_WAKEUP(m[i]);
+ m[i]->flags &= ~PG_FAKE;
+ } else {
+ vnode_pager_freepage(m[i]);
+ }
+ }
+ }
+ if (!error && rw == UIO_WRITE) {
+ pmap_clear_modify(VM_PAGE_TO_PHYS(m[reqpage]));
+ m[reqpage]->flags |= PG_CLEAN;
+ m[reqpage]->flags &= ~PG_LAUNDRY;
}
- vm_pager_unmap_page(kva);
+ if (error) {
+ printf("vnode pager error: %d\n", error);
+ }
+ if (errtype)
+ return error;
return (error ? VM_PAGER_FAIL : VM_PAGER_OK);
}
-#endif
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