Give the page allocations initiated by the swap-backed md(4) a higher

priority.  If the write is requested by a system daemon, sleeping
there would starve resources and cause deadlock.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
kib 2013-08-30 20:12:23 +00:00
parent 6eb9415a25
commit 36259bf9a2

View File

@ -826,7 +826,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
vm_object_pip_add(sc->object, 1);
for (i = bp->bio_offset / PAGE_SIZE; i <= lastp; i++) {
len = ((i == lastp) ? lastend : PAGE_SIZE) - offs;
m = vm_page_grab(sc->object, i, VM_ALLOC_NORMAL);
m = vm_page_grab(sc->object, i, VM_ALLOC_SYSTEM);
if (bp->bio_cmd == BIO_READ) {
if (m->valid == VM_PAGE_BITS_ALL)
rv = VM_PAGER_OK;