Page MenuHomeFreeBSD
Files F148320170

D22409.id64455.diff
No OneTemporary
Actions

D22409.id64455.diff
View Options

Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -421,11 +421,13 @@
* Metadata functions
*/
static daddr_t swp_pager_meta_build(vm_object_t, vm_pindex_t, daddr_t);
+static daddr_t swp_pager_meta_lookup(vm_object_t object, vm_pindex_t pindex0,
+ int *before, int *after);
static void swp_pager_meta_free(vm_object_t, vm_pindex_t, vm_pindex_t);
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_ctl(vm_object_t, vm_pindex_t, int);
+static daddr_t swp_pager_meta_remove(vm_object_t, vm_pindex_t);
static void
swp_pager_init_freerange(daddr_t *start, daddr_t *num)
@@ -941,7 +943,8 @@
{
daddr_t dstaddr;
- if (swp_pager_meta_ctl(dstobject, pindex, 0) != SWAPBLK_NONE) {
+ if (swp_pager_meta_lookup(dstobject, pindex, NULL, NULL)
+ != SWAPBLK_NONE) {
/* Caller should destroy the source block. */
return (false);
}
@@ -1045,15 +1048,15 @@
swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
int *after)
{
- daddr_t blk, blk0;
- int i;
+ daddr_t blk0;
- VM_OBJECT_ASSERT_LOCKED(object);
+ if (before)
+ *before = SWB_NPAGES - 1;
+ if (after)
+ *after = SWB_NPAGES - 1;
- /*
- * do we have good backing store at the requested index ?
- */
- blk0 = swp_pager_meta_ctl(object, pindex, 0);
+ VM_OBJECT_ASSERT_LOCKED(object);
+ blk0 = swp_pager_meta_lookup(object, pindex, before, after);
if (blk0 == SWAPBLK_NONE) {
if (before)
*before = 0;
@@ -1062,31 +1065,6 @@
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_ctl(object, pindex - i, 0);
- 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_ctl(object, pindex + i, 0);
- if (blk != blk0 + i)
- break;
- }
- *after = i - 1;
- }
return (TRUE);
}
@@ -1114,7 +1092,7 @@
{
daddr_t srcaddr;
- srcaddr = swp_pager_meta_ctl(m->object, m->pindex, SWM_POP);
+ srcaddr = swp_pager_meta_remove(m->object, m->pindex);
if (srcaddr != SWAPBLK_NONE)
swp_pager_freeswapspace(srcaddr, 1);
}
@@ -1210,7 +1188,7 @@
vm_object_pip_add(object, count);
pindex = bm->pindex;
- blk = swp_pager_meta_ctl(object, pindex, 0);
+ blk = swp_pager_meta_lookup(object, pindex, NULL, NULL);
KASSERT(blk != SWAPBLK_NONE,
("no swap blocking containing %p(%jx)", object, (uintmax_t)pindex));
@@ -2101,28 +2079,127 @@
}
/*
- * 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.
*
+ * 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 pindex0, int *before,
+ int *after)
+{
+ struct swblk *sb, *sbb;
+ vm_pindex_t pindex, pindexb;
+ daddr_t r0;
+ int i, i0, end, offset;
+
+ VM_OBJECT_ASSERT_LOCKED(object);
+ /*
+ * The meta data only exists if the object is OBJT_SWAP
+ * and even then might not be allocated yet.
+ */
+ if (object->type != OBJT_SWAP)
+ return (SWAPBLK_NONE);
+
+ 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);
+ r0 = sb->d[i0];
+
+ if (before) {
+ 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)
+ 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);
+}
+
+/*
+ * SWP_PAGER_META_REMOVE() - remove swap meta data.
+ *
+ * This routine is capable of removing swapblk assignments in the
+ * swap meta data. It returns the swapblk being removed or
+ * SWAPBLK_NONE if the block was invalid.
+ *
* 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.
- *
- * SWM_POP remove from meta data but do not free it
*/
static daddr_t
-swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
+swp_pager_meta_remove(vm_object_t object, vm_pindex_t pindex)
{
struct swblk *sb;
daddr_t r1;
- if ((flags & SWM_POP) != 0)
- VM_OBJECT_ASSERT_WLOCKED(object);
- else
- VM_OBJECT_ASSERT_LOCKED(object);
+ VM_OBJECT_ASSERT_LOCKED(object);
/*
* The meta data only exists if the object is OBJT_SWAP
@@ -2138,13 +2215,11 @@
r1 = sb->d[pindex % SWAP_META_PAGES];
if (r1 == SWAPBLK_NONE)
return (SWAPBLK_NONE);
- if ((flags & SWM_POP) != 0) {
- sb->d[pindex % SWAP_META_PAGES] = SWAPBLK_NONE;
- if (swp_pager_swblk_empty(sb, 0, SWAP_META_PAGES)) {
- SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks,
- rounddown(pindex, SWAP_META_PAGES));
- uma_zfree(swblk_zone, sb);
- }
+ sb->d[pindex % SWAP_META_PAGES] = SWAPBLK_NONE;
+ if (swp_pager_swblk_empty(sb, 0, SWAP_META_PAGES)) {
+ SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks,
+ rounddown(pindex, SWAP_META_PAGES));
+ uma_zfree(swblk_zone, sb);
}
return (r1);
}

File Metadata

Mime Type
text/plain
Expires
Wed, Mar 18, 3:58 AM (17 h, 48 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
29877336
Default Alt Text
D22409.id64455.diff (7 KB)

Event Timeline