diff options
Diffstat (limited to 'sys/vm/default_pager.c')
| -rw-r--r-- | sys/vm/default_pager.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/sys/vm/default_pager.c b/sys/vm/default_pager.c index 98dee45..012a220 100644 --- a/sys/vm/default_pager.c +++ b/sys/vm/default_pager.c @@ -63,6 +63,16 @@ static boolean_t default_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); /* * pagerops for OBJT_DEFAULT - "default pager". + * + * This pager handles anonymous (no handle) swap-backed memory, just + * like the swap pager. It allows several optimizations based on the + * fact that no pages of a default object can be swapped out. The + * most important optimization is in vm_fault(), where the pager is + * never asked for a non-resident page. Instead, a freshly allocated + * zeroed page is used. + * + * On the first request to page out a page from a default object, the + * object is converted to swap pager type. */ struct pagerops defaultpagerops = { .pgo_alloc = default_pager_alloc, |
