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diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -2199,9 +2199,11 @@
{
struct page_range range;
struct swblk *sb;
- daddr_t blk;
+ daddr_t blk, d[SWAP_META_PAGES];
vm_pindex_t offset, last;
- int i, limit, start;
+ int d_mask, i, limit, start;
+ _Static_assert(8 * sizeof(d_mask) >= SWAP_META_PAGES,
+ "d_mask not big enough");
VM_OBJECT_ASSERT_WLOCKED(srcobject);
VM_OBJECT_ASSERT_WLOCKED(dstobject);
@@ -2210,39 +2212,50 @@
return;
swp_pager_init_freerange(&range);
+ d_mask = 0;
offset = pindex;
last = pindex + count;
sb = swblk_start_limit(srcobject, pindex, last);
start = (sb != NULL && sb->p < pindex) ? pindex - sb->p : 0;
for (; sb != NULL;
sb = swblk_start_limit(srcobject, pindex, last), start = 0) {
- limit = MIN(last - sb->p, SWAP_META_PAGES);
+ pindex = sb->p;
+ MPASS(d_mask == 0);
+ limit = MIN(last - pindex, SWAP_META_PAGES);
for (i = start; i < limit; i++) {
if (sb->d[i] == SWAPBLK_NONE)
continue;
blk = swp_pager_meta_build(dstobject,
- sb->p + i - offset, sb->d[i], true);
+ pindex + i - offset, sb->d[i], true);
if (blk == sb->d[i]) {
/*
- * Destination has no swapblk and is not
- * resident, so transfer source.
- * swp_pager_meta_build() failed memory
- * allocation already, likely to sleep in retry.
+ * Failed memory allocation stopped transfer;
+ * save this block for transfer with lock
+ * released.
*/
- VM_OBJECT_WUNLOCK(srcobject);
- swp_pager_meta_build(dstobject,
- sb->p + i - offset, sb->d[i], false);
- VM_OBJECT_WLOCK(srcobject);
+ d[i] = blk;
+ d_mask |= 1 << i;
} else if (blk != SWAPBLK_NONE)
swp_pager_update_freerange(&range, sb->d[i]);
sb->d[i] = SWAPBLK_NONE;
}
- pindex = sb->p + SWAP_META_PAGES;
if (swp_pager_swblk_empty(sb, 0, start) &&
swp_pager_swblk_empty(sb, limit, SWAP_META_PAGES)) {
swblk_lookup_remove(srcobject, sb);
uma_zfree(swblk_zone, sb);
}
+ if (d_mask != 0) {
+ /* Finish block transfer, with the lock released. */
+ VM_OBJECT_WUNLOCK(srcobject);
+ do {
+ i = ffs(d_mask) - 1;
+ swp_pager_meta_build(dstobject,
+ pindex + i - offset, d[i], false);
+ d_mask &= ~(1 << i);
+ } while (d_mask != 0);
+ VM_OBJECT_WLOCK(srcobject);
+ }
+ pindex += SWAP_META_PAGES;
}
swp_pager_freeswapspace(&range);
}

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