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-rw-r--r--sys/vm/swap_pager.c511
1 files changed, 503 insertions, 8 deletions
diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 752974c0e01c..faf90759e33d 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -2,7 +2,7 @@
* Copyright (c) 1998 Matthew Dillon,
* Copyright (c) 1994 John S. Dyson
* Copyright (c) 1990 University of Utah.
- * Copyright (c) 1991, 1993
+ * Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
@@ -63,11 +63,16 @@
* from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
*
* @(#)swap_pager.c 8.9 (Berkeley) 3/21/94
+ * @(#)vm_swap.c 8.5 (Berkeley) 2/17/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
+#include "opt_mac.h"
+#include "opt_swap.h"
+#include "opt_vm.h"
+
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
@@ -75,15 +80,20 @@ __FBSDID("$FreeBSD$");
#include <sys/proc.h>
#include <sys/bio.h>
#include <sys/buf.h>
+#include <sys/disk.h>
+#include <sys/fcntl.h>
+#include <sys/mount.h>
+#include <sys/namei.h>
#include <sys/vnode.h>
+#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/sysctl.h>
+#include <sys/sysproto.h>
#include <sys/blist.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/vmmeter.h>
-#include "opt_swap.h"
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
@@ -92,10 +102,35 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_pageout.h>
+#include <vm/vm_param.h>
#include <vm/swap_pager.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
+#ifndef NSWAPDEV
+#define NSWAPDEV 4
+#endif
+
+typedef int32_t swblk_t; /* swap offset */
+
+struct swblock {
+ struct swblock *swb_hnext;
+ vm_object_t swb_object;
+ vm_pindex_t swb_index;
+ int swb_count;
+ daddr_t swb_pages[SWAP_META_PAGES];
+};
+
+static struct swdevt should_be_malloced[NSWAPDEV];
+static struct swdevt *swdevt = should_be_malloced;
+static int nswap; /* first block after the interleaved devs */
+static int nswdev = NSWAPDEV;
+int vm_swap_size;
+static int swdev_syscall_active = 0; /* serialize swap(on|off) */
+
+static int swapdev_strategy(struct vop_strategy_args *ap);
+static struct vnode *swapdev_vp;
+
#define SWM_FREE 0x02 /* free, period */
#define SWM_POP 0x04 /* pop out */
@@ -131,8 +166,8 @@ SYSCTL_INT(_vm, OID_AUTO, swap_async_max,
static struct mtx sw_alloc_mtx; /* protect list manipulation */
static struct pagerlst swap_pager_object_list[NOBJLISTS];
-struct pagerlst swap_pager_un_object_list;
-uma_zone_t swap_zone;
+static struct pagerlst swap_pager_un_object_list;
+static uma_zone_t swap_zone;
/*
* pagerops for OBJT_SWAP - "swap pager". Some ops are also global procedure
@@ -149,6 +184,7 @@ static boolean_t
static void swap_pager_init(void);
static void swap_pager_unswapped(vm_page_t);
static void swap_pager_strategy(vm_object_t, struct bio *);
+static void swap_pager_swapoff(int devidx, int *sw_used);
struct pagerops swappagerops = {
swap_pager_init, /* early system initialization of pager */
@@ -172,9 +208,9 @@ static void waitchainbuf(struct bio *bp, int count, int done);
* swap_*() routines are externally accessible. swp_*() routines are
* internal.
*/
-int dmmax, dmmax_mask;
-int nswap_lowat = 128; /* in pages, swap_pager_almost_full warn */
-int nswap_hiwat = 512; /* in pages, swap_pager_almost_full warn */
+static int dmmax, dmmax_mask;
+static int nswap_lowat = 128; /* in pages, swap_pager_almost_full warn */
+static int nswap_hiwat = 512; /* in pages, swap_pager_almost_full warn */
SYSCTL_INT(_vm, OID_AUTO, dmmax,
CTLFLAG_RD, &dmmax, 0, "Maximum size of a swap block");
@@ -1738,7 +1774,7 @@ swp_pager_force_pagein(struct swblock *swap, int idx)
*
* This routine may block.
*/
-void
+static void
swap_pager_swapoff(int devidx, int *sw_used)
{
struct swblock **pswap;
@@ -2205,3 +2241,462 @@ waitchainbuf(struct bio *bp, int limit, int done)
splx(s);
}
+/*
+ * swapdev_strategy:
+ *
+ * VOP_STRATEGY() for swapdev_vp.
+ * Perform swap strategy interleave device selection.
+ *
+ * The bp is expected to be locked and *not* B_DONE on call.
+ */
+static int
+swapdev_strategy(ap)
+ struct vop_strategy_args /* {
+ struct vnode *a_vp;
+ struct buf *a_bp;
+ } */ *ap;
+{
+ int s, sz, off, seg, index;
+ struct swdevt *sp;
+ struct vnode *vp;
+ struct buf *bp;
+
+ KASSERT(ap->a_vp == ap->a_bp->b_vp, ("%s(%p != %p)",
+ __func__, ap->a_vp, ap->a_bp->b_vp));
+ bp = ap->a_bp;
+ sz = howmany(bp->b_bcount, PAGE_SIZE);
+
+ /*
+ * Convert interleaved swap into per-device swap. Note that
+ * the block size is left in PAGE_SIZE'd chunks (for the newswap)
+ * here.
+ */
+ if (nswdev > 1) {
+ off = bp->b_blkno % dmmax;
+ if (off + sz > dmmax) {
+ bp->b_error = EINVAL;
+ bp->b_ioflags |= BIO_ERROR;
+ bufdone(bp);
+ return 0;
+ }
+ seg = bp->b_blkno / dmmax;
+ index = seg % nswdev;
+ seg /= nswdev;
+ bp->b_blkno = seg * dmmax + off;
+ } else {
+ index = 0;
+ }
+ sp = &swdevt[index];
+ if (bp->b_blkno + sz > sp->sw_nblks) {
+ bp->b_error = EINVAL;
+ bp->b_ioflags |= BIO_ERROR;
+ bufdone(bp);
+ return 0;
+ }
+ bp->b_dev = sp->sw_device;
+ if (sp->sw_vp == NULL) {
+ bp->b_error = ENODEV;
+ bp->b_ioflags |= BIO_ERROR;
+ bufdone(bp);
+ return 0;
+ }
+
+ /*
+ * Convert from PAGE_SIZE'd to DEV_BSIZE'd chunks for the actual I/O
+ */
+ bp->b_blkno = ctodb(bp->b_blkno);
+
+ vhold(sp->sw_vp);
+ s = splvm();
+ if (bp->b_iocmd == BIO_WRITE) {
+ vp = bp->b_vp;
+ if (vp) {
+ VI_LOCK(vp);
+ vp->v_numoutput--;
+ if ((vp->v_iflag & VI_BWAIT) && vp->v_numoutput <= 0) {
+ vp->v_iflag &= ~VI_BWAIT;
+ wakeup(&vp->v_numoutput);
+ }
+ VI_UNLOCK(vp);
+ }
+ VI_LOCK(sp->sw_vp);
+ sp->sw_vp->v_numoutput++;
+ VI_UNLOCK(sp->sw_vp);
+ }
+ bp->b_vp = sp->sw_vp;
+ splx(s);
+ if (bp->b_vp->v_type == VCHR)
+ VOP_SPECSTRATEGY(bp->b_vp, bp);
+ else
+ VOP_STRATEGY(bp->b_vp, bp);
+ return 0;
+}
+
+/*
+ * Create a special vnode op vector for swapdev_vp - we only use
+ * VOP_STRATEGY() and reclaim; everything else returns an error.
+ */
+vop_t **swapdev_vnodeop_p;
+static struct vnodeopv_entry_desc swapdev_vnodeop_entries[] = {
+ { &vop_default_desc, (vop_t *) vop_defaultop },
+ { &vop_reclaim_desc, (vop_t *) vop_null },
+ { &vop_strategy_desc, (vop_t *) swapdev_strategy },
+ { NULL, NULL }
+};
+static struct vnodeopv_desc swapdev_vnodeop_opv_desc =
+ { &swapdev_vnodeop_p, swapdev_vnodeop_entries };
+
+VNODEOP_SET(swapdev_vnodeop_opv_desc);
+
+/*
+ * System call swapon(name) enables swapping on device name,
+ * which must be in the swdevsw. Return EBUSY
+ * if already swapping on this device.
+ */
+#ifndef _SYS_SYSPROTO_H_
+struct swapon_args {
+ char *name;
+};
+#endif
+
+/*
+ * MPSAFE
+ */
+/* ARGSUSED */
+int
+swapon(td, uap)
+ struct thread *td;
+ struct swapon_args *uap;
+{
+ struct vattr attr;
+ struct vnode *vp;
+ struct nameidata nd;
+ int error;
+
+ mtx_lock(&Giant);
+ error = suser(td);
+ if (error)
+ goto done2;
+
+ while (swdev_syscall_active)
+ tsleep(&swdev_syscall_active, PUSER - 1, "swpon", 0);
+ swdev_syscall_active = 1;
+
+ /*
+ * Swap metadata may not fit in the KVM if we have physical
+ * memory of >1GB.
+ */
+ if (swap_zone == NULL) {
+ error = ENOMEM;
+ goto done;
+ }
+
+ NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, td);
+ error = namei(&nd);
+ if (error)
+ goto done;
+
+ NDFREE(&nd, NDF_ONLY_PNBUF);
+ vp = nd.ni_vp;
+
+ if (vn_isdisk(vp, &error))
+ error = swaponvp(td, vp, vp->v_rdev, 0);
+ else if (vp->v_type == VREG &&
+ (vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
+ (error = VOP_GETATTR(vp, &attr, td->td_ucred, td)) == 0) {
+ /*
+ * Allow direct swapping to NFS regular files in the same
+ * way that nfs_mountroot() sets up diskless swapping.
+ */
+ error = swaponvp(td, vp, NODEV, attr.va_size / DEV_BSIZE);
+ }
+
+ if (error)
+ vrele(vp);
+done:
+ swdev_syscall_active = 0;
+ wakeup_one(&swdev_syscall_active);
+done2:
+ mtx_unlock(&Giant);
+ return (error);
+}
+
+/*
+ * Swfree(index) frees the index'th portion of the swap map.
+ * Each of the nswdev devices provides 1/nswdev'th of the swap
+ * space, which is laid out with blocks of dmmax pages circularly
+ * among the devices.
+ *
+ * The new swap code uses page-sized blocks. The old swap code used
+ * DEV_BSIZE'd chunks.
+ */
+int
+swaponvp(td, vp, dev, nblks)
+ struct thread *td;
+ struct vnode *vp;
+ dev_t dev;
+ u_long nblks;
+{
+ int index;
+ struct swdevt *sp;
+ swblk_t vsbase;
+ long blk;
+ swblk_t dvbase;
+ int error;
+ u_long aligned_nblks;
+ off_t mediasize;
+
+ if (!swapdev_vp) {
+ error = getnewvnode("none", NULL, swapdev_vnodeop_p,
+ &swapdev_vp);
+ if (error)
+ panic("Cannot get vnode for swapdev");
+ swapdev_vp->v_type = VNON; /* Untyped */
+ }
+
+ ASSERT_VOP_UNLOCKED(vp, "swaponvp");
+ for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) {
+ if (sp->sw_vp == vp)
+ return EBUSY;
+ if (!sp->sw_vp)
+ goto found;
+
+ }
+ return EINVAL;
+ found:
+ (void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
+#ifdef MAC
+ error = mac_check_system_swapon(td->td_ucred, vp);
+ if (error == 0)
+#endif
+ error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td);
+ (void) VOP_UNLOCK(vp, 0, td);
+ if (error)
+ return (error);
+
+ if (nblks == 0) {
+ error = VOP_IOCTL(vp, DIOCGMEDIASIZE, (caddr_t)&mediasize,
+ FREAD, td->td_ucred, td);
+ if (error == 0)
+ nblks = mediasize / DEV_BSIZE;
+ }
+ /*
+ * XXX: We should also check that the sectorsize makes sense
+ * XXX: it should be a power of two, no larger than the page size.
+ */
+ if (nblks == 0) {
+ (void) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
+ return (ENXIO);
+ }
+
+ /*
+ * If we go beyond this, we get overflows in the radix
+ * tree bitmap code.
+ */
+ if (nblks > 0x40000000 / BLIST_META_RADIX / nswdev) {
+ printf("exceeded maximum of %d blocks per swap unit\n",
+ 0x40000000 / BLIST_META_RADIX / nswdev);
+ (void) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
+ return (ENXIO);
+ }
+ /*
+ * nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks.
+ * First chop nblks off to page-align it, then convert.
+ *
+ * sw->sw_nblks is in page-sized chunks now too.
+ */
+ nblks &= ~(ctodb(1) - 1);
+ nblks = dbtoc(nblks);
+
+ sp->sw_vp = vp;
+ sp->sw_dev = dev2udev(dev);
+ sp->sw_device = dev;
+ sp->sw_flags = SW_FREED;
+ sp->sw_nblks = nblks;
+ sp->sw_used = 0;
+
+ /*
+ * nblks, nswap, and dmmax are PAGE_SIZE'd parameters now, not
+ * DEV_BSIZE'd. aligned_nblks is used to calculate the
+ * size of the swap bitmap, taking into account the stripe size.
+ */
+ aligned_nblks = (nblks + (dmmax -1)) & ~(u_long)(dmmax -1);
+
+ if (aligned_nblks * nswdev > nswap)
+ nswap = aligned_nblks * nswdev;
+
+ if (swapblist == NULL)
+ swapblist = blist_create(nswap);
+ else
+ blist_resize(&swapblist, nswap, 0);
+
+ for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
+ blk = min(nblks - dvbase, dmmax);
+ vsbase = index * dmmax + dvbase * nswdev;
+ blist_free(swapblist, vsbase, blk);
+ vm_swap_size += blk;
+ }
+
+ swap_pager_full = 0;
+
+ return (0);
+}
+
+/*
+ * SYSCALL: swapoff(devname)
+ *
+ * Disable swapping on the given device.
+ */
+#ifndef _SYS_SYSPROTO_H_
+struct swapoff_args {
+ char *name;
+};
+#endif
+
+/*
+ * MPSAFE
+ */
+/* ARGSUSED */
+int
+swapoff(td, uap)
+ struct thread *td;
+ struct swapoff_args *uap;
+{
+ struct vnode *vp;
+ struct nameidata nd;
+ struct swdevt *sp;
+ swblk_t dvbase, vsbase;
+ u_long nblks, aligned_nblks, blk;
+ int error, index;
+
+ mtx_lock(&Giant);
+
+ error = suser(td);
+ if (error)
+ goto done2;
+
+ while (swdev_syscall_active)
+ tsleep(&swdev_syscall_active, PUSER - 1, "swpoff", 0);
+ swdev_syscall_active = 1;
+
+ NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, td);
+ error = namei(&nd);
+ if (error)
+ goto done;
+ NDFREE(&nd, NDF_ONLY_PNBUF);
+ vp = nd.ni_vp;
+
+ for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) {
+ if (sp->sw_vp == vp)
+ goto found;
+ }
+ error = EINVAL;
+ goto done;
+found:
+#ifdef MAC
+ (void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
+ error = mac_check_system_swapoff(td->td_ucred, vp);
+ (void) VOP_UNLOCK(vp, 0, td);
+ if (error != 0)
+ goto done;
+#endif
+
+ nblks = sp->sw_nblks;
+
+ /*
+ * We can turn off this swap device safely only if the
+ * available virtual memory in the system will fit the amount
+ * of data we will have to page back in, plus an epsilon so
+ * the system doesn't become critically low on swap space.
+ */
+ if (cnt.v_free_count + cnt.v_cache_count + vm_swap_size <
+ nblks + nswap_lowat) {
+ error = ENOMEM;
+ goto done;
+ }
+
+ /*
+ * Prevent further allocations on this device.
+ */
+ sp->sw_flags |= SW_CLOSING;
+ for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
+ blk = min(nblks - dvbase, dmmax);
+ vsbase = index * dmmax + dvbase * nswdev;
+ vm_swap_size -= blist_fill(swapblist, vsbase, blk);
+ }
+
+ /*
+ * Page in the contents of the device and close it.
+ */
+#ifndef NO_SWAPPING
+ vm_proc_swapin_all(index);
+#endif /* !NO_SWAPPING */
+ swap_pager_swapoff(index, &sp->sw_used);
+
+ VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
+ vrele(vp);
+ sp->sw_vp = NULL;
+
+ /*
+ * Resize the bitmap based on the new largest swap device,
+ * or free the bitmap if there are no more devices.
+ */
+ for (sp = swdevt, nblks = 0; sp < swdevt + nswdev; sp++) {
+ if (sp->sw_vp == NULL)
+ continue;
+ nblks = max(nblks, sp->sw_nblks);
+ }
+
+ aligned_nblks = (nblks + (dmmax -1)) & ~(u_long)(dmmax -1);
+ nswap = aligned_nblks * nswdev;
+
+ if (nswap == 0) {
+ blist_destroy(swapblist);
+ swapblist = NULL;
+ vrele(swapdev_vp);
+ swapdev_vp = NULL;
+ } else
+ blist_resize(&swapblist, nswap, 0);
+
+done:
+ swdev_syscall_active = 0;
+ wakeup_one(&swdev_syscall_active);
+done2:
+ mtx_unlock(&Giant);
+ return (error);
+}
+
+static int
+sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
+{
+ int *name = (int *)arg1;
+ int error, i, n;
+ struct xswdev xs;
+ struct swdevt *sp;
+
+ if (arg2 != 1) /* name length */
+ return (EINVAL);
+
+ for (sp = swdevt, i = 0, n = 0 ; i < nswdev; i++, sp++) {
+ if (sp->sw_vp) {
+ if (n == *name) {
+ xs.xsw_version = XSWDEV_VERSION;
+ xs.xsw_dev = sp->sw_dev;
+ xs.xsw_flags = sp->sw_flags;
+ xs.xsw_nblks = sp->sw_nblks;
+ xs.xsw_used = sp->sw_used;
+
+ error = SYSCTL_OUT(req, &xs, sizeof(xs));
+ return (error);
+ }
+ n++;
+ }
+
+ }
+ return (ENOENT);
+}
+
+SYSCTL_INT(_vm, OID_AUTO, nswapdev, CTLFLAG_RD, &nswdev, 0,
+ "Number of swap devices");
+SYSCTL_NODE(_vm, OID_AUTO, swap_info, CTLFLAG_RD, sysctl_vm_swap_info,
+ "Swap statistics by device");
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-09 19:23:44 +0000