(either the current protection or the max protection) that reference
vnodes associated with a file system mounted with the NOEXEC option.
uvm_mmap(): Don't allow PROT_EXEC mappings to be established of vnodes
which are associated with a file system mounted with the NOEXEC option.
executable mappings. Stop overloading VTEXT for this purpose (VTEXT
also has another meaning).
- Rename vn_marktext() to vn_markexec(), and use it when executable
mappings of a vnode are established.
- In places where we want to set VTEXT, set it in v_flag directly, rather
than making a function call to do this (it no longer makes sense to
use a function call, since we no longer overload VTEXT with VEXECMAP's
meaning).
VEXECMAP suggested by Chuq Silvers.
- remove special treatment of pager_map mappings in pmaps. this is
required now, since I've removed the globals that expose the address range.
pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
no longer any need to special-case it.
- eliminate struct uvm_vnode by moving its fields into struct vnode.
- rewrite the pageout path. the pager is now responsible for handling the
high-level requests instead of only getting control after a bunch of work
has already been done on its behalf. this will allow us to UBCify LFS,
which needs tighter control over its pages than other filesystems do.
writing a page to disk no longer requires making it read-only, which
allows us to write wired pages without causing all kinds of havoc.
- use a new PG_PAGEOUT flag to indicate that a page should be freed
on behalf of the pagedaemon when it's unlocked. this flag is very similar
to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
pageout fails due to eg. an indirect-block buffer being locked.
this allows us to remove the "version" field from struct vm_page,
and together with shrinking "loan_count" from 32 bits to 16,
struct vm_page is now 4 bytes smaller.
- no longer use PG_RELEASED for swap-backed pages. if the page is busy
because it's being paged out, we can't release the swap slot to be
reallocated until that write is complete, but unlike with vnodes we
don't keep a count of in-progress writes so there's no good way to
know when the write is done. instead, when we need to free a busy
swap-backed page, just sleep until we can get it busy ourselves.
- implement a fast-path for extending writes which allows us to avoid
zeroing new pages. this substantially reduces cpu usage.
- encapsulate the data used by the genfs code in a struct genfs_node,
which must be the first element of the filesystem-specific vnode data
for filesystems which use genfs_{get,put}pages().
- eliminate many of the UVM pagerops, since they aren't needed anymore
now that the pager "put" operation is a higher-level operation.
- enhance the genfs code to allow NFS to use the genfs_{get,put}pages
instead of a modified copy.
- clean up struct vnode by removing all the fields that used to be used by
the vfs_cluster.c code (which we don't use anymore with UBC).
- remove kmem_object and mb_object since they were useless.
instead of allocating pages to these objects, we now just allocate
pages with no object. such pages are mapped in the kernel until they
are freed, so we can use the mapping to find the page to free it.
this allows us to remove splvm() protection in several places.
The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.
This will allow improvements to the pmaps so that they can more easily defer expensive operations, eg tlb/cache flush, til the last possible moment.
Currently this is a no-op on most platforms, so they should see no difference.
Reviewed by Jason.
kernel_map. use this instead of the static map entries when allocating
map entries for kernel_map. this greatly reduces the number of static
map entries used and should eliminate the problems with running out.
algorithm (Solaris calls this "Bin Hopping").
This implementation currently relies on MD code to define a
constant defining the number of buckets. This will change
reasonably soon (MD code will be able to dynamically size
the bucket array).
- pmap_enter()
- pmap_remove()
- pmap_protect()
- pmap_kenter_pa()
- pmap_kremove()
as described in pmap(9).
These calls are relatively conservative. It may be possible to
optimize these a little more.
space is already torn down in uvmspace_free() when the vmspace
refrence count reaches 0. Move the shmexit() call into uvmspace_free().
Note that there is a beneficial side-effect of deferring the unmap
to uvmspace_free() -- on systems where TLB invalidations are
particularly expensive, the unmapping of the address space won't
have to cause TLB invalidations; uvmspace_free() is going to be
run in a context other than the exiting process's, so the "pmap is
active" test will evaluate to FALSE in the pmap module.
entry in the map. the old code would walk around the end of the linked list,
through the header entry, and keep going from the first map entry until it
found a gap in the map, at which point it would return an error. if the map
had no gaps then it would loop forever. reported by k-abe@cs.utah.edu.
while I'm here, clean up this function a bit.
also, use MIN() instead of min(), since the latter takes arguments of
type "int" but we're passing it values of type "vaddr_t", which can be
a larger size.
Mach VM's now. Specific changes:
- Pages now need not have all of their mappings removed before being
put on the inactive list. They only need to have the "referenced"
attribute cleared. This makes putting pages onto the inactive list
much more efficient. In order to eliminate redundant clearings of
"refrenced", callers of uvm_pagedeactivate() must now do this
themselves.
- When checking the "modified" attribute for a page (for clearing
PG_CLEAN), make sure to only do it if PG_CLEAN is currently set on
the page (saves a potentially expensive pmap operation).
- When scanning the inactive list, if a page is referenced, reactivate
it (this part was actually added in uvm_pdaemon.c,v 1.27). This
now works properly now that pages on the inactive list are allowed to
have mappings.
- When scanning the inactive list and considering a page for freeing,
remove all mappings, and then check the "modified" attribute if the
page is marked PG_CLEAN.
- When scanning the active list, if the page was referenced since its
last sweep by the scanner, don't deactivate it. (This part was
actually added in uvm_pdaemon.c,v 1.28.)
These changes greatly improve interactive performance during
moderate to high memory and I/O load.
use queue.h macros and KASSERT().
address amap offsets in pages instead of bytes.
make amap_ref() and amap_unref() take an amap, offset and length
instead of a vm_map_entry_t.
improve whitespace and comments.
it and free it as appropriate. Activate p2's new address space once
it references p1's.
- uvm_fork(): Make sure the child's vmspace is NULL before calling
uvmspace_share() (the child doens't have one already in this case).
These changes do not change the behavior for the current use of
uvmspace_share() (vfork(2)), but make it possible for an already
running process (such as a kernel thread) to properly attach to
another process's address space.
to the contents of the hint in the map, and the hint saved in the
map only if the two values match. When an unconditional save is
required, the "check" value passed should be map->hint (and the
compiler will optimize the test away). When deleting a map entry,
the new SAVE_HINT() will only change the hint if the entry being
deleted was the hint value (thus preserving any meaningful hint
that may have been there previously, rather than stomping on it).
- Add a missing hint update when deleting the map entry in
uvm_map_entry_unlink(). This is the fix for kern/11125, from
ITOH Yasufumi <itohy@netbsd.org>.
routine. Works similarly fto pmap_prefer(), but allows callers
to specify a minimum power-of-two alignment of the region.
How we ever got along without this for so long is beyond me.
<vm/pglist.h> -> <uvm/uvm_pglist.h>
<vm/vm_inherit.h> -> <uvm/uvm_inherit.h>
<vm/vm_kern.h> -> into <uvm/uvm_extern.h>
<vm/vm_object.h> -> nothing
<vm/vm_pager.h> -> into <uvm/uvm_pager.h>
also includes a bunch of <vm/vm_page.h> include removals (due to redudancy
with <vm/vm.h>), and a scattering of other similar headers.
- Make page free lists have two actual queues: known-zero pages and
pages with unknown contents.
- Implement uvm_pageidlezero(). This function attempts to zero up to
the target number of pages until the target has been reached (currently
target is `all free pages') or until whichqs becomes non-zero (indicating
that a process is ready to run).
- Define a new hook for the pmap module for pre-zero'ing pages. This is
used to zero the pages using uncached access. This allows us to zero
as many pages as we want without polluting the cache.
In order to use this feature, each platform must add the appropropriate
glue in their idle loop.
one pmap and activating another. this isn't actually necessary (since
pmap_activate() and pmap_deactivate() affect only user-level mappings,
which cannot be accessed from interrupts anyway), and pmap_activate()
is very slow on old sun4c sparcs so we can't block interrupts for this long.
this fixes PR 8322.
Add a new type voff_t (defined as a synonym for off_t) to describe offsets
into uvm objects, and update the appropriate interfaces to use it, the
most visible effect being the ability to mmap() file offsets beyond
the range of a vaddr_t.
Originally by Chuck Silvers; blame me for problems caused by merging this
into non-UBC.
- Fix some locking bugs; a couple of places would return an error condition
without unlocking the map.
- Deal with maps marked WIREFUTURE; if making an entry VM_PROT_NONE ->
anything else, and it is not already marked as wired, wire it.
