diff options
| author | dillon <dillon@FreeBSD.org> | 2000-05-29 22:40:54 +0000 |
|---|---|---|
| committer | dillon <dillon@FreeBSD.org> | 2000-05-29 22:40:54 +0000 |
| commit | 82627e96a026e438a7251b0e5dc0a5322435693c (patch) | |
| tree | 30efad495e652bce5e17011dd662ffce150ecd07 /sys/kern/sysv_shm.c | |
| parent | 2e7f60e876b44bc7a2762fa018f17c30864bc19d (diff) | |
| download | FreeBSD-src-82627e96a026e438a7251b0e5dc0a5322435693c.zip FreeBSD-src-82627e96a026e438a7251b0e5dc0a5322435693c.tar.gz | |
This is a cleanup patch to Peter's new OBJT_PHYS VM object type
and sysv shared memory support for it. It implements a new
PG_UNMANAGED flag that has slightly different characteristics
from PG_FICTICIOUS.
A new sysctl, kern.ipc.shm_use_phys has been added to enable the
use of physically-backed sysv shared memory rather then swap-backed.
Physically backed shm segments are not tracked with PV entries,
allowing programs which use a large shm segment as a rendezvous
point to operate without eating an insane amount of KVM in the
PV entry management. Read: Oracle.
Peter's OBJT_PHYS object will also allow us to eventually implement
page-table sharing and/or 4MB physical page support for such segments.
We're half way there.
Diffstat (limited to 'sys/kern/sysv_shm.c')
| -rw-r--r-- | sys/kern/sysv_shm.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/sys/kern/sysv_shm.c b/sys/kern/sysv_shm.c index 16019dc..11a5568 100644 --- a/sys/kern/sysv_shm.c +++ b/sys/kern/sysv_shm.c @@ -126,12 +126,15 @@ struct shminfo shminfo = { SHMALL }; +static int shm_use_phys; + SYSCTL_DECL(_kern_ipc); SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, ""); static int shm_find_segment_by_key(key) @@ -528,13 +531,13 @@ shmget_allocate_segment(p, uap, mode) * We make sure that we have allocated a pager before we need * to. */ -#ifdef SHM_PHYS_BACKED - shm_handle->shm_object = - vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); -#else - shm_handle->shm_object = - vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); -#endif + if (shm_use_phys) { + shm_handle->shm_object = + vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); + } else { + shm_handle->shm_object = + vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); + } vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); |
