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, 23 insertions, 4 deletions

diff --git a/vm/vm_page.c b/vm/vm_page.c
index a539ab41..48d70964 100644
--- a/vm/vm_page.c
+++ b/vm/vm_page.c
@@ -442,6 +442,9 @@ vm_page_seg_alloc(struct vm_page_seg *seg, unsigned int order,
         simple_lock(&seg->lock);
         page = vm_page_seg_alloc_from_buddy(seg, order);
         simple_unlock(&seg->lock);
+
+        if (page == NULL)
+            return NULL;
     }
 
     assert(page->type == VM_PT_FREE);
@@ -637,10 +640,6 @@ vm_page_setup(void)
             page->type = VM_PT_FREE;
             vm_page_seg_free_to_buddy(seg, page, 0);
             page++;
-
-            /* XXX */
-            if (i <= VM_PAGE_SEG_DIRECTMAP)
-                vm_page_free_count++;
         }
 
         table += vm_page_atop(vm_page_seg_size(seg));
@@ -705,6 +704,7 @@ vm_page_alloc_pa(unsigned int order, unsigned int selector, unsigned short type)
 void
 vm_page_free_pa(struct vm_page *page, unsigned int order)
 {
+    assert(page != NULL);
     assert(page->seg_index < ARRAY_SIZE(vm_page_segs));
 
     vm_page_seg_free(&vm_page_segs[page->seg_index], page, order);
@@ -760,3 +760,22 @@ vm_page_mem_size(void)
 
     return total;
 }
+
+unsigned long
+vm_page_mem_free(void)
+{
+    unsigned long total;
+    unsigned int i;
+
+    total = 0;
+
+    for (i = 0; i < vm_page_segs_size; i++) {
+        /* XXX */
+        if (i >  VM_PAGE_SEG_DIRECTMAP)
+            continue;
+
+        total += vm_page_segs[i].nr_free_pages;
+    }
+
+    return total;
+}