diff options
| -rw-r--r-- | sys/amd64/amd64/pmap.c | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 215a4f1..0c87c35 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -4765,10 +4765,12 @@ pmap_remove_write(vm_page_t m) { struct md_page *pvh; pmap_t pmap; + struct rwlock *lock; pv_entry_t next_pv, pv; pd_entry_t *pde; pt_entry_t oldpte, *pte; vm_offset_t va; + int pvh_gen, md_gen; KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("pmap_remove_write: page %p is not managed", m)); @@ -4781,23 +4783,51 @@ pmap_remove_write(vm_page_t m) VM_OBJECT_ASSERT_WLOCKED(m->object); if (!vm_page_xbusied(m) && (m->aflags & PGA_WRITEABLE) == 0) return; - rw_wlock(&pvh_global_lock); + rw_rlock(&pvh_global_lock); + lock = VM_PAGE_TO_PV_LIST_LOCK(m); + pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m)); +retry_pv_loop: + rw_wlock(lock); if ((m->flags & PG_FICTITIOUS) != 0) goto small_mappings; - pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m)); TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_next, next_pv) { pmap = PV_PMAP(pv); - PMAP_LOCK(pmap); + if (!PMAP_TRYLOCK(pmap)) { + pvh_gen = pvh->pv_gen; + rw_wunlock(lock); + PMAP_LOCK(pmap); + rw_wlock(lock); + if (pvh_gen != pvh->pv_gen) { + PMAP_UNLOCK(pmap); + rw_wunlock(lock); + goto retry_pv_loop; + } + } va = pv->pv_va; pde = pmap_pde(pmap, va); if ((*pde & PG_RW) != 0) - (void)pmap_demote_pde(pmap, pde, va); + (void)pmap_demote_pde_locked(pmap, pde, va, &lock); + KASSERT(lock == VM_PAGE_TO_PV_LIST_LOCK(m), + ("inconsistent pv lock %p %p for page %p", + lock, VM_PAGE_TO_PV_LIST_LOCK(m), m)); PMAP_UNLOCK(pmap); } small_mappings: TAILQ_FOREACH(pv, &m->md.pv_list, pv_next) { pmap = PV_PMAP(pv); - PMAP_LOCK(pmap); + if (!PMAP_TRYLOCK(pmap)) { + pvh_gen = pvh->pv_gen; + md_gen = m->md.pv_gen; + rw_wunlock(lock); + PMAP_LOCK(pmap); + rw_wlock(lock); + if (pvh_gen != pvh->pv_gen || + md_gen != m->md.pv_gen) { + PMAP_UNLOCK(pmap); + rw_wunlock(lock); + goto retry_pv_loop; + } + } pde = pmap_pde(pmap, pv->pv_va); KASSERT((*pde & PG_PS) == 0, ("pmap_remove_write: found a 2mpage in page %p's pv list", @@ -4815,8 +4845,9 @@ retry: } PMAP_UNLOCK(pmap); } + rw_wunlock(lock); vm_page_aflag_clear(m, PGA_WRITEABLE); - rw_wunlock(&pvh_global_lock); + rw_runlock(&pvh_global_lock); } /* |
