vm object hasn't changed, the desired page will be at or near the root
of the vm object's splay tree, making vm_page_lookup() cheap. (The only
lock required for vm_page_lookup() is already held.) If, however, the
vm object has changed and retry was requested, eliminating the generation
check also eliminates a pointless acquisition and release of the page
queues lock.
This guard page would have trapped the problems with the MFC of the PAE
support to RELENG_4 at an earlier point in the sequence of events.
Submitted by: tegge
vm_pageout_scan(). Rationale: I don't like leaving a busy page in the
cache queue with neither the vm object nor the vm page queues lock held.
- Assert that the page is active in vm_pageout_page_stats().
pmap_copy_page() et al. to accept a vm_page_t rather than a physical
address. Also, this change will facilitate locking access to the vm page's
valid field.
color in vm_page_alloc(). (This also has small performance benefits.)
- Eliminate vm_page_select_free(); vm_page_alloc() might as well
call vm_pageq_find() directly.
releasing the lock only if we are about to sleep (e.g., vm_pager_get_pages()
or vm_pager_has_pages()). If we sleep, we have marked the vm object with
the paging-in-progress flag.
- Remove the Giant required from vm_page_free_toq(). (Any locking
errors will be caught by vm_page_remove().)
This remedies a panic that occurred when kmem_malloc(NOWAIT) performed
without Giant failed to allocate the necessary pages.
Reported by: phk
called without Giant; and obj_alloc() in turn calls vm_page_alloc()
without Giant. This causes an assertion failure in vm_page_alloc().
Fortunately, obj_alloc() is now MPSAFE. So, we need only clean up
some assertions.
- Weaken the assertion in vm_page_lookup() to require Giant only
if the vm_object isn't locked.
- Remove an assertion from vm_page_alloc() that duplicates a check
performed in vm_page_lookup().
In collaboration with: gallatin, jake, jeff
where physical addresses larger than virtual addresses, such as i386s
with PAE.
- Use this to represent physical addresses in the MI vm system and in the
i386 pmap code. This also changes the paddr parameter to d_mmap_t.
- Fix printf formats to handle physical addresses >4G in the i386 memory
detection code, and due to kvtop returning vm_paddr_t instead of u_long.
Note that this is a name change only; vm_paddr_t is still the same as
vm_offset_t on all currently supported platforms.
Sponsored by: DARPA, Network Associates Laboratories
Discussed with: re, phk (cdevsw change)
The objective being to eliminate some cases of page queues locking.
(See, for example, vm/vm_fault.c revision 1.160.)
Reviewed by: tegge
(Also, pointed out by tegge that I changed vm_fault.c before changing
vm_page.c. Oops.)
requests when the number of free pages is below the reserved threshold.
Previously, VM_ALLOC_ZERO was only honored when the number of free pages
was above the reserved threshold. Honoring it in all cases generally
makes sense, does no harm, and simplifies the code.
