diff options
| author | Alan Cox <alc@FreeBSD.org> | 2021-06-30 05:59:21 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2021-08-31 19:09:23 +0000 |
| commit | 605e07a27ecb2e32732a0750622f9a960a982071 (patch) | |
| tree | 6444a5bd89faad3c2716edcdeda8a03c1b21ab34 | |
| parent | b2727ab88c8d2b2974124c3c2929b16e20949200 (diff) | |
| download | src-605e07a27ecb2e32732a0750622f9a960a982071.tar.gz src-605e07a27ecb2e32732a0750622f9a960a982071.zip | |
amd64: a simplication to pmap_remove_{all,write}
Eliminate some unnecessary unlocking and relocking when we have to retry
the operation to avoid deadlock. (All of the other pmap functions that
iterate over a PV list already implemented retries without these same
unlocking and relocking operations.)
Reviewed by: kib, markj
(cherry picked from commit 1a8bcf30f97e6153def2af781db2fe54f5c0d106)
| -rw-r--r-- | sys/amd64/amd64/pmap.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index d35422924b1f..16dcddc7786a 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -6192,8 +6192,8 @@ pmap_remove_all(vm_page_t m) lock = VM_PAGE_TO_PV_LIST_LOCK(m); pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : pa_to_pvh(VM_PAGE_TO_PHYS(m)); -retry: rw_wlock(lock); +retry: while ((pv = TAILQ_FIRST(&pvh->pv_list)) != NULL) { pmap = PV_PMAP(pv); if (!PMAP_TRYLOCK(pmap)) { @@ -6202,7 +6202,6 @@ retry: PMAP_LOCK(pmap); rw_wlock(lock); if (pvh_gen != pvh->pv_gen) { - rw_wunlock(lock); PMAP_UNLOCK(pmap); goto retry; } @@ -6221,7 +6220,6 @@ retry: PMAP_LOCK(pmap); rw_wlock(lock); if (pvh_gen != pvh->pv_gen || md_gen != m->md.pv_gen) { - rw_wunlock(lock); PMAP_UNLOCK(pmap); goto retry; } @@ -8348,8 +8346,8 @@ pmap_remove_write(vm_page_t m) lock = VM_PAGE_TO_PV_LIST_LOCK(m); pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : pa_to_pvh(VM_PAGE_TO_PHYS(m)); -retry_pv_loop: rw_wlock(lock); +retry_pv_loop: TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_next, next_pv) { pmap = PV_PMAP(pv); if (!PMAP_TRYLOCK(pmap)) { @@ -8359,7 +8357,6 @@ retry_pv_loop: rw_wlock(lock); if (pvh_gen != pvh->pv_gen) { PMAP_UNLOCK(pmap); - rw_wunlock(lock); goto retry_pv_loop; } } @@ -8384,7 +8381,6 @@ retry_pv_loop: if (pvh_gen != pvh->pv_gen || md_gen != m->md.pv_gen) { PMAP_UNLOCK(pmap); - rw_wunlock(lock); goto retry_pv_loop; } } |