little or no swap.
- even on a severe swap shortage, if we have some amount of file-backed pages,
don't bother to kill processes.
- if all pages in queue will be likely reactivated, just give up
page type balancing rather than spinning unnecessarily.
fix "warning: resource shortage: %d pages of swap lost".
extent(9) has some undesirable characteristics for swap allocation:
- it involves alloc-to-free.
- its operational cost is O(n*n) where n is number of entries.
- don't use managed mappings/backing objects for wired memory allocations.
save some resources like pv_entry. also fix (most of) PR/27030.
- simplify kernel memory management API.
- simplify pmap bootstrap of some ports.
- some related cleanups.
* For sparc64 and amd64, define *SIZ32 VM constants.
* Add a new function pointer to struct emul, pointing at a function
that will return the default VM map address. The default function
is uvm_map_defaultaddr, which just uses the VM_DEFAULT_ADDRESS
macro. This gives emulations control over the default map address,
and allows things to be mapped at the right address (in 32bit range)
for COMPAT_NETBSD32.
* Add code to adjust the data and stack limits when a COMPAT_NETBSD32
or COMPAT_SVR4_32 binary is executed.
* Don't use USRSTACK in kern_resource.c, use p_vmspace->vm_minsaddr
instead (emulations might have set it differently)
* Since this changes struct emul, bump kernel version to 3.99.2
Tested on amd64, compile-tested on sparc64.
define and use vm_map_set{min,max}() for modifying these values.
remove the {min,max}_offset aliases for these vm_map fields to be more
namespace-friendly. PR 26475.
to four (adding size and direction).
In order for topdown uvm to be an option on ports using PMAP_PREFER,
they will need to "prefer" lower addresses if topdown is being used.
Additionally, at least one port also needs to know the size.
(namely exec_map and phys_map) becuase:
- normal vmmpepl is fine for them.
- some of them are tightly sized. eg. size of exec_map on vax is just NCARGS.
should fix vax boot failure reported by Johnny Billquist on current-users@.
this means we can no longer look at the vnode size to determine how many
pages to request in a fault, which is good since for NFS the size can change
out from under us on the server anyway. there's also a new flag UBC_UNMAP
for ubc_release(), so that the file system code can make the decision about
whether to cache mappings for files being used as executables.
- allocate kva for vm_map_entry from the map itsself and
remove the static limit, MAX_KMAPENT.
- keep merged entries for later splitting to fix allocate-to-free problem.
PR/24039.
- decrement uvmexp.anonpages as it's no longer an anon page.
- null out anon->u.an_page as the anon no longer own the page.
uvm_anfree: add related assertions.
