From 7cd53fdda8de9ad5f7de3a599f7a544c844d99cd Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Thu, 18 Mar 2004 18:23:37 +0000 Subject: Utilize sf_buf_alloc() and sf_buf_free() to implement the ephemeral mappings required by mdstart_swap(). On i386, if the ephemeral mapping is already in the sf_buf mapping cache, a swap-backed md performs similarly to a malloc-backed md. Even if the ephemeral mapping is not cached, this implementation is still faster. On 64-bit platforms, this change has the effect of using the direct virtual-to-physical mapping, avoiding ephemeral mapping overheads, such as TLB shootdowns on SMPs. On a 2.4GHz, 400MHz FSB P4 Xeon configured with 64K sf_bufs and "mdmfs -S -o async -s 128m md /mnt" before: dd if=/dev/md0 of=/dev/null bs=64k 134217728 bytes transferred in 0.430923 secs (311465697 bytes/sec) after with cold sf_buf cache: dd if=/dev/md0 of=/dev/null bs=64k 134217728 bytes transferred in 0.367948 secs (364773576 bytes/sec) after with warm sf_buf cache: dd if=/dev/md0 of=/dev/null bs=64k 134217728 bytes transferred in 0.252826 secs (530870010 bytes/sec) malloc-backed md: dd if=/dev/md0 of=/dev/null bs=64k 134217728 bytes transferred in 0.253126 secs (530240978 bytes/sec) --- sys/dev/md/md.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'sys/dev') diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c index 006f07fafa67..8036f1923af2 100644 --- a/sys/dev/md/md.c +++ b/sys/dev/md/md.c @@ -75,6 +75,7 @@ #include #include #include +#include #include #include @@ -523,11 +524,11 @@ static int mdstart_swap(struct md_s *sc, struct bio *bp) { { + struct sf_buf *sf; int i, rv; int offs, len, lastp, lastend; vm_page_t m; u_char *p; - vm_offset_t kva; p = bp->bio_data; @@ -542,8 +543,6 @@ mdstart_swap(struct md_s *sc, struct bio *bp) lastp = (bp->bio_offset + bp->bio_length - 1) / PAGE_SIZE; lastend = (bp->bio_offset + bp->bio_length - 1) % PAGE_SIZE + 1; - kva = kmem_alloc_nofault(kernel_map, PAGE_SIZE); - VM_OBJECT_LOCK(sc->object); vm_object_pip_add(sc->object, 1); for (i = bp->bio_offset / PAGE_SIZE; i <= lastp; i++) { @@ -551,20 +550,22 @@ mdstart_swap(struct md_s *sc, struct bio *bp) m = vm_page_grab(sc->object, i, VM_ALLOC_NORMAL|VM_ALLOC_RETRY); - pmap_qenter(kva, &m, 1); + VM_OBJECT_UNLOCK(sc->object); + sf = sf_buf_alloc(m); + 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); } - bcopy((void *)(kva + offs), p, len); + bcopy((void *)(sf_buf_kva(sf) + offs), p, len); } else if (bp->bio_cmd == BIO_WRITE) { if (len != PAGE_SIZE && m->valid != VM_PAGE_BITS_ALL) { rv = vm_pager_get_pages(sc->object, &m, 1, 0); } - bcopy(p, (void *)(kva + offs), len); + bcopy(p, (void *)(sf_buf_kva(sf) + offs), len); m->valid = VM_PAGE_BITS_ALL; #if 0 } else if (bp->bio_cmd == BIO_DELETE) { @@ -573,12 +574,12 @@ mdstart_swap(struct md_s *sc, struct bio *bp) rv = vm_pager_get_pages(sc->object, &m, 1, 0); } - bzero((void *)(kva + offs), len); + bzero((void *)(sf_buf_kva(sf) + offs), len); vm_page_dirty(m); m->valid = VM_PAGE_BITS_ALL; #endif } - pmap_qremove(kva, 1); + sf_buf_free(sf); vm_page_lock_queues(); vm_page_wakeup(m); vm_page_activate(m); @@ -600,7 +601,6 @@ printf("wire_count %d busy %d flags %x hold_count %d act_count %d queue %d valid vm_object_pip_subtract(sc->object, 1); vm_object_set_writeable_dirty(sc->object); VM_OBJECT_UNLOCK(sc->object); - kmem_free(kernel_map, kva, sc->secsize); return (0); } } -- cgit v1.3