Fix various memory managment errors

A few errors were introduced in the latest changes.

o Add VM_PAGE_WAIT calls around physical allocation attempts in case of
memory exhaustion.
o Fix stack release.
o Fix memory exhaustion report.
o Fix free page accounting.

* kern/slab.c (kmem_pagealloc, kmem_pagefree): New functions
(kmem_slab_create, kmem_slab_destroy, kalloc, kfree): Use kmem_pagealloc
and kmem_pagefree instead of the raw page allocation functions.
(kmem_cache_compute_sizes): Don't store slab order.
* kern/slab.h (struct kmem_cache): Remove `slab_order' member.
* kern/thread.c (stack_alloc): Call VM_PAGE_WAIT in case of memory
exhaustion.
(stack_collect): Call vm_page_free_contig instead of kmem_free to
release pages.
* vm/vm_page.c (vm_page_seg_alloc): Fix memory exhaustion report.
(vm_page_setup): Don't update vm_page_free_count.
(vm_page_free_pa): Check page parameter.
(vm_page_mem_free): New function.
* vm/vm_page.h (vm_page_free_count): Remove extern declaration.
(vm_page_mem_free): New prototype.
* vm/vm_pageout.c: Update comments not to refer to vm_page_free_count.
(vm_pageout_scan, vm_pageout_continue, vm_pageout): Use vm_page_mem_free
instead of vm_page_free_count, update types accordingly.
* vm/vm_resident.c (vm_page_free_count, vm_page_free_count_minimum):
Remove variables.
(vm_page_free_avail): New variable.
(vm_page_bootstrap, vm_page_grab, vm_page_release, vm_page_grab_contig,
vm_page_free_contig, vm_page_wait): Use vm_page_mem_free instead of vm_page_free_count,
update types accordingly, don't set vm_page_free_count_minimum.
* vm/vm_user.c (vm_statistics): Likewise.

1 files changed, 12 insertions, 2 deletions

diff --git a/vm/vm_page.h b/vm/vm_page.h
index 4e870d82..6f4f3c22 100644
--- a/vm/vm_page.h
+++ b/vm/vm_page.h
@@ -162,8 +162,6 @@ extern
 queue_head_t	vm_page_queue_inactive;	/* inactive memory queue */
 
 extern
-int	vm_page_free_count;	/* How many pages are free? */
-extern
 int	vm_page_fictitious_count;/* How many fictitious pages are free? */
 extern
 int	vm_page_active_count;	/* How many pages are active? */
@@ -483,12 +481,16 @@ struct vm_page * vm_page_lookup_pa(phys_addr_t pa);
  *
  * The selector is used to determine the segments from which allocation can
  * be attempted.
+ *
+ * This function should only be used by the vm_resident module.
  */
 struct vm_page * vm_page_alloc_pa(unsigned int order, unsigned int selector,
                                   unsigned short type);
 
 /*
  * Release a block of 2^order physical pages.
+ *
+ * This function should only be used by the vm_resident module.
  */
 void vm_page_free_pa(struct vm_page *page, unsigned int order);
 
@@ -507,4 +509,12 @@ void vm_page_info_all(void);
  */
 phys_addr_t vm_page_mem_size(void);
 
+/*
+ * Return the amount of free (unused) pages.
+ *
+ * XXX This currently relies on the kernel being non preemptible and
+ * uniprocessor.
+ */
+unsigned long vm_page_mem_free(void);
+
 #endif	/* _VM_VM_PAGE_H_ */