Change Details

vm_page_free_prep(): convert PG_ZERO zeroed page check to use sf_buf Make the check MI by allocating sf_buf in non-blockable manner. For DMAP arches, this should be nop since sf_buf allocation cannot fail. For non-DMAP arches, we get the checks activated unless there is serious sf_buf pressure, which typically should be not. The context for vm_page_free_prep() should be ready to block on some VM mutexes, which should make it reasonable to block on sf_buf list lock. vm_fault: under DIAGNOSTIC, verify that PG_ZERO page is indeed zeroed

vm_page_free_prep(): convert PG_ZERO zeroed page check to use sf_buf Make the check MI by allocating sf_buf in non-blockable manner. For DMAP arches, this should be nop since sf_buf allocation cannot fail. For non-DMAP arches, we get the checks activated unless there is serious sf_buf pressure, which typically should be not. The context for vm_page_free_prep() should be ready to block on some VM mutexes, which should make it reasonable to block on sf_buf list lock. Move the code to INVARIANTS build, and control it with the sysctl debug.vm_check_pg_zero. vm_fault: under INVARIANTS, add the verifier that PG_ZERO page is indeed zeroed Controlled by the same sysctl debug.vm_check_pg_zero.

vm_page_free_prep(): convert PG_ZERO zeroed page check to use sf_buf Make the check MI by allocating sf_buf in non-blockable manner. For DMAP arches, this should be nop since sf_buf allocation cannot fail. For non-DMAP arches, we get the checks activated unless there is serious sf_buf pressure, which typically should be not. The context for vm_page_free_prep() should be ready to block on some VM mutexes, which should make it reasonable to block on sf_buf list lock. Move the code to INVARIANTS build, and control it with the sysctl debug.vm_check_pg_zero. vm_fault: under INVARIANTS, add the verifier that PG_ZERO page is indeed zeroed vm_fault: under DIAGNOSTIC, verify that PG_ZERO page is indeed Controlled by the same sysctl debug.vm_check_pg_zeroed.