diff options
| -rw-r--r-- | sys/i386/i386/vm_machdep.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c index 4452acf..97582a3 100644 --- a/sys/i386/i386/vm_machdep.c +++ b/sys/i386/i386/vm_machdep.c @@ -617,6 +617,7 @@ sf_buf_init(void *arg) struct sf_buf * sf_buf_alloc(struct vm_page *m, int pri) { + pt_entry_t opte, *ptep; struct sf_head *hash_list; struct sf_buf *sf; int error; @@ -655,7 +656,20 @@ sf_buf_alloc(struct vm_page *m, int pri) sf->m = m; nsfbufsused++; nsfbufspeak = imax(nsfbufspeak, nsfbufsused); - pmap_qenter(sf->kva, &sf->m, 1); + + /* + * Update the sf_buf's virtual-to-physical mapping, flushing the + * virtual address from the TLB only if the PTE implies that the old + * mapping has been used. Since the reference count for the sf_buf's + * old mapping was zero, that mapping is not currently in use. + * Consequently, there is no need to exchange the old and new PTEs + * atomically, even under PAE. + */ + ptep = vtopte(sf->kva); + opte = *ptep; + *ptep = VM_PAGE_TO_PHYS(m) | pgeflag | PG_RW | PG_V; + if ((opte & (PG_A | PG_V)) == (PG_A | PG_V)) + pmap_invalidate_page(kernel_pmap, sf->kva); done: mtx_unlock(&sf_buf_lock); return (sf); |
