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Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -424,7 +424,8 @@
static void swp_pager_meta_transfer(vm_object_t src, vm_object_t dst,
vm_pindex_t pindex, vm_pindex_t count);
static void swp_pager_meta_free_all(vm_object_t);
-static daddr_t swp_pager_meta_lookup(vm_object_t, vm_pindex_t);
+static daddr_t swp_pager_meta_lookup(vm_object_t object, vm_pindex_t pindex0,
+ int *before, int *after);
static void
swp_pager_init_freerange(daddr_t *start, daddr_t *num)
@@ -943,7 +944,8 @@
KASSERT(srcobject->type == OBJT_SWAP,
("%s: Srcobject not swappable", __func__));
if (dstobject->type == OBJT_SWAP &&
- swp_pager_meta_lookup(dstobject, pindex) != SWAPBLK_NONE) {
+ swp_pager_meta_lookup(dstobject, pindex, NULL, NULL) !=
+ SWAPBLK_NONE) {
/* Caller should destroy the source block. */
return (false);
}
@@ -1047,17 +1049,18 @@
swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
int *after)
{
- daddr_t blk, blk0;
- int i;
+ daddr_t blk0;
+ if (before)
+ *before = SWB_NPAGES - 1;
+ if (after)
+ *after = SWB_NPAGES - 1;
+
VM_OBJECT_ASSERT_LOCKED(object);
KASSERT(object->type == OBJT_SWAP,
("%s: object not swappable", __func__));
- /*
- * do we have good backing store at the requested index ?
- */
- blk0 = swp_pager_meta_lookup(object, pindex);
+ blk0 = swp_pager_meta_lookup(object, pindex, before, after);
if (blk0 == SWAPBLK_NONE) {
if (before)
*before = 0;
@@ -1066,31 +1069,6 @@
return (FALSE);
}
- /*
- * find backwards-looking contiguous good backing store
- */
- if (before != NULL) {
- for (i = 1; i < SWB_NPAGES; i++) {
- if (i > pindex)
- break;
- blk = swp_pager_meta_lookup(object, pindex - i);
- if (blk != blk0 - i)
- break;
- }
- *before = i - 1;
- }
-
- /*
- * find forward-looking contiguous good backing store
- */
- if (after != NULL) {
- for (i = 1; i < SWB_NPAGES; i++) {
- blk = swp_pager_meta_lookup(object, pindex + i);
- if (blk != blk0 + i)
- break;
- }
- *after = i - 1;
- }
return (TRUE);
}
@@ -1231,7 +1209,7 @@
vm_object_pip_add(object, count);
pindex = bm->pindex;
- blk = swp_pager_meta_lookup(object, pindex);
+ blk = swp_pager_meta_lookup(object, pindex, NULL, NULL);
KASSERT(blk != SWAPBLK_NONE,
("no swap blocking containing %p(%jx)", object, (uintmax_t)pindex));
@@ -2138,20 +2116,32 @@
}
/*
- * SWP_PAGER_METACTL() - misc control of swap meta data.
+ * SWP_PAGER_META_LOOKUP() - lookup good backing store for
+ * the requested page and optionally the number of continuous blocks.
*
- * This routine is capable of looking up, or removing swapblk
- * assignments in the swap meta data. It returns the swapblk being
- * looked-up, popped, or SWAPBLK_NONE if the block was invalid.
+ * This routine looks up swapblk assignment in the swap meta data.
+ * In addition, if before and/or after are provided with a limit value,
+ * it looks for the number of continuous blocks backward and forward.
*
- * When acting on a busy resident page and paging is in progress, we
- * have to wait until paging is complete but otherwise can act on the
- * busy page.
+ * This returns SWAPBLK_NONE if swblk at pindex isn't associated to
+ * swap meta data; *before and *after are not modified for this case.
+ * Otherwise, return the swap address of pindex. If *before and/or
+ * *after are provided with positive numbers, the number of continuous
+ * blocks before and/or after up to provided limits are searched and
+ * returned.
+ *
+ * Input - "object" and "pindex0"
+ * Input/Output - "before" and "after" - the number of continuous blocks
+ * to look for as input and its actual size as output.
*/
static daddr_t
-swp_pager_meta_lookup(vm_object_t object, vm_pindex_t pindex)
+swp_pager_meta_lookup(vm_object_t object, vm_pindex_t pindex0, int *before,
+ int *after)
{
- struct swblk *sb;
+ struct swblk *sb, *sbb;
+ vm_pindex_t pindex, pindexb;
+ daddr_t r0;
+ int i, i0, end, offset;
VM_OBJECT_ASSERT_LOCKED(object);
@@ -2162,11 +2152,72 @@
KASSERT(object->type == OBJT_SWAP,
("Lookup object not swappable"));
- sb = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks,
- rounddown(pindex, SWAP_META_PAGES));
- if (sb == NULL)
+ i0 = pindex0 % SWAP_META_PAGES;
+ pindex = rounddown(pindex0, SWAP_META_PAGES);
+
+ sb = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks, pindex);
+ if (sb == NULL || sb->d[i0] == SWAPBLK_NONE)
return (SWAPBLK_NONE);
- return (sb->d[pindex % SWAP_META_PAGES]);
+ r0 = sb->d[i0];
+
+ if (before != NULL) {
+ if (*before <= 0 || pindex0 == 0) {
+ *before = 0;
+ goto finished_backward;
+ }
+ offset = 1;
+ pindexb = pindex;
+ sbb = sb;
+ if (pindex0 < *before) /* some pindexes are less than 0. */
+ end = pindex0;
+ else
+ end = *before;
+ i = i0 - 1;
+ do {
+ for (; i >= 0; --i, ++offset) {
+ if (r0 - offset != sbb->d[i]) {
+ *before = offset - 1;
+ goto finished_backward;
+ }
+ if (offset == end) {
+ *before = offset;
+ goto finished_backward;
+ }
+ }
+ pindexb -= SWAP_META_PAGES;
+ i = SWAP_META_PAGES - 1;
+ } while ((sbb = SWAP_PCTRIE_LOOKUP(
+ &object->un_pager.swp.swp_blks, pindexb)) != NULL);
+ *before = offset - 1;
+ }
+finished_backward:
+ if (after == NULL)
+ return (r0);
+ if (*after <= 0) {
+ *after = 0;
+ return (r0);
+ }
+
+ offset = 1;
+ end = *after; /* how do I check overflow? */
+ i = i0 + 1;
+ do {
+ for (; i < SWAP_META_PAGES; ++i, ++offset) {
+ if (r0 + offset != sb->d[i]) {
+ *after = offset - 1;
+ return (r0);
+ }
+ if (offset == end) {
+ *after = offset;
+ return (r0);
+ }
+ }
+ pindex += SWAP_META_PAGES;
+ i = 0;
+ } while ((sb = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks,
+ pindex)) != NULL);
+ *after = offset - 1;
+ return (r0);
}
/*

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