From e340fc602be23c05a35f023bb91e70b4148c2ad9 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Sun, 13 Feb 2005 21:51:50 +0000 Subject: [PATCH] Request a CPU private mapping from sf_buf_alloc(). If the swap-backed memory disk is larger than the number of available sf_bufs, this improves performance on SMPs by eliminating interprocessor TLB shootdowns. For example, with 6656 sf_bufs, the default on my test machine, and a 256MB swap-backed memory disk, I see the command "dd if=/dev/md0 of=/dev/null bs=64k" achieve ~489MB/sec with the default, shared mappings, and ~587MB/sec with CPU private mappings. --- sys/dev/md/md.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c index 041c511ef5b..908d123cf0e 100644 --- a/sys/dev/md/md.c +++ b/sys/dev/md/md.c @@ -552,13 +552,15 @@ mdstart_swap(struct md_s *sc, struct bio *bp) m = vm_page_grab(sc->object, i, VM_ALLOC_NORMAL|VM_ALLOC_RETRY); VM_OBJECT_UNLOCK(sc->object); - sf = sf_buf_alloc(m, 0); + sched_pin(); + sf = sf_buf_alloc(m, SFB_CPUPRIVATE); VM_OBJECT_LOCK(sc->object); if (bp->bio_cmd == BIO_READ) { if (m->valid != VM_PAGE_BITS_ALL) rv = vm_pager_get_pages(sc->object, &m, 1, 0); if (rv == VM_PAGER_ERROR) { sf_buf_free(sf); + sched_unpin(); vm_page_lock_queues(); vm_page_wakeup(m); vm_page_unlock_queues(); @@ -570,6 +572,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp) rv = vm_pager_get_pages(sc->object, &m, 1, 0); if (rv == VM_PAGER_ERROR) { sf_buf_free(sf); + sched_unpin(); vm_page_lock_queues(); vm_page_wakeup(m); vm_page_unlock_queues(); @@ -583,6 +586,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp) rv = vm_pager_get_pages(sc->object, &m, 1, 0); if (rv == VM_PAGER_ERROR) { sf_buf_free(sf); + sched_unpin(); vm_page_lock_queues(); vm_page_wakeup(m); vm_page_unlock_queues(); @@ -594,6 +598,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp) #endif } sf_buf_free(sf); + sched_unpin(); vm_page_lock_queues(); vm_page_wakeup(m); vm_page_activate(m);