diff options
| author | attilio <attilio@FreeBSD.org> | 2012-06-23 02:08:15 +0000 |
|---|---|---|
| committer | attilio <attilio@FreeBSD.org> | 2012-06-23 02:08:15 +0000 |
| commit | 5d9dd820d8dbc25b32304a51fb32d3ac2e2a88e5 (patch) | |
| tree | 4d0464daafa331a0f98cca9a1273d2355181ea1e /sys/vm/vm_object.h | |
| parent | a8dc1f52704aa713258258a5479ff5f815b8606f (diff) | |
| parent | e19c8fe0ffaebe2cb325b0d14102166d51b7429d (diff) | |
| download | FreeBSD-src-5d9dd820d8dbc25b32304a51fb32d3ac2e2a88e5.zip FreeBSD-src-5d9dd820d8dbc25b32304a51fb32d3ac2e2a88e5.tar.gz | |
MFC
Diffstat (limited to 'sys/vm/vm_object.h')
| -rw-r--r-- | sys/vm/vm_object.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h index 6aa9f5f..a386150 100644 --- a/sys/vm/vm_object.h +++ b/sys/vm/vm_object.h @@ -78,8 +78,21 @@ * * vm_object_t Virtual memory object. * + * The root of cached pages pool is protected by both the per-object mutex + * and the free pages queue mutex. + * On insert in the cache splay tree, the per-object mutex is expected + * to be already held and the free pages queue mutex will be + * acquired during the operation too. + * On remove and lookup from the cache splay tree, only the free + * pages queue mutex is expected to be locked. + * These rules allow for reliably checking for the presence of cached + * pages with only the per-object lock held, thereby reducing contention + * for the free pages queue mutex. + * * List of locks * (c) const until freed + * (o) per-object mutex + * (f) free pages queue mutex * */ |
