diff options
author | alc <alc@FreeBSD.org> | 2012-03-17 22:04:58 +0000 |
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committer | alc <alc@FreeBSD.org> | 2012-03-17 22:04:58 +0000 |
commit | eb494d678de962a38a167f6340ee1f70f7473fa5 (patch) | |
tree | da5389ff077505348dd3b2575f921381bd962ef6 | |
parent | 26b44e3c9dec81c45a5cd5e5386ca5b6c9a06953 (diff) | |
download | FreeBSD-src-eb494d678de962a38a167f6340ee1f70f7473fa5.zip FreeBSD-src-eb494d678de962a38a167f6340ee1f70f7473fa5.tar.gz |
With the changes over the past year to how accesses to the page's dirty
field are synchronized, there is no need for pmap_protect() to acquire
the page queues lock unless it is going to access the pv lists.
Reviewed by: kib
-rw-r--r-- | sys/amd64/amd64/pmap.c | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 4c7bd2f..1289a38 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -2940,6 +2940,7 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot) pd_entry_t ptpaddr, *pde; pt_entry_t *pte; int anychanged; + boolean_t pv_lists_locked; if ((prot & VM_PROT_READ) == VM_PROT_NONE) { pmap_remove(pmap, sva, eva); @@ -2950,9 +2951,10 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot) (VM_PROT_WRITE|VM_PROT_EXECUTE)) return; + pv_lists_locked = FALSE; +resume: anychanged = 0; - vm_page_lock_queues(); PMAP_LOCK(pmap); for (; sva < eva; sva = va_next) { @@ -3001,9 +3003,25 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot) if (pmap_protect_pde(pmap, pde, sva, prot)) anychanged = 1; continue; - } else if (!pmap_demote_pde(pmap, pde, sva)) { - /* The large page mapping was destroyed. */ - continue; + } else { + if (!pv_lists_locked) { + pv_lists_locked = TRUE; + if (!mtx_trylock(&vm_page_queue_mtx)) { + if (anychanged) + pmap_invalidate_all( + pmap); + PMAP_UNLOCK(pmap); + vm_page_lock_queues(); + goto resume; + } + } + if (!pmap_demote_pde(pmap, pde, sva)) { + /* + * The large page mapping was + * destroyed. + */ + continue; + } } } @@ -3043,7 +3061,8 @@ retry: } if (anychanged) pmap_invalidate_all(pmap); - vm_page_unlock_queues(); + if (pv_lists_locked) + vm_page_unlock_queues(); PMAP_UNLOCK(pmap); } |