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| author | Alan Cox <alc@FreeBSD.org> | 2021-06-30 05:59:21 +0000 |
|---|---|---|
| committer | Alan Cox <alc@FreeBSD.org> | 2021-06-30 18:12:25 +0000 |
| commit | 1a8bcf30f97e6153def2af781db2fe54f5c0d106 (patch) | |
| tree | ea0f2a953090305a28561e07a55d96a4a4104f7a | |
| parent | 3f197b101f71ee4f4949c53bf330f61b43749ce9 (diff) | |
| download | src-1a8bcf30f97e6153def2af781db2fe54f5c0d106.tar.gz src-1a8bcf30f97e6153def2af781db2fe54f5c0d106.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
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30951
| -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 a4046cc1f687..ea017b8a61a8 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -6307,8 +6307,8 @@ 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)) { @@ -6317,7 +6317,6 @@ retry: PMAP_LOCK(pmap); rw_wlock(lock); if (pvh_gen != pvh->pv_gen) { - rw_wunlock(lock); PMAP_UNLOCK(pmap); goto retry; } @@ -6336,7 +6335,6 @@ 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; } @@ -8460,8 +8458,8 @@ 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)) { @@ -8471,7 +8469,6 @@ retry_pv_loop: rw_wlock(lock); if (pvh_gen != pvh->pv_gen) { PMAP_UNLOCK(pmap); - rw_wunlock(lock); goto retry_pv_loop; } } @@ -8496,7 +8493,6 @@ 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; } } |