Changeset 7be8d4d in mainline for kernel/generic/src/mm/backend_elf.c

Timestamp:

2018-12-08T23:32:55Z (5 years ago)

Author:

Jiri Svoboda <jiri@…>

Children:

dd74b5b

Parents:

de0af3a

git-author:

Jiri Svoboda <jiri@…> (2018-12-05 18:39:06)

git-committer:

Jiri Svoboda <jiri@…> (2018-12-08 23:32:55)

Message:

Replace B+tree with ordered dict. for used space

Replace the use of B+tree with ordered dictionary for used space,
adding a little bit more abstraction around used space tracking.
This allows performing TLB shootdown while shrinking an area
in a single sequence. A generic used_space_remove() is no longer
needed.

File:

• kernel/generic/src/mm/backend_elf.c (modified) (5 diffs)

kernel/generic/src/mm/backend_elf.c

@@ -153 +153 @@
 {
         elf_segment_header_t *entry = area->backend_data.segment;
-        link_t *cur;
-        btree_node_t *leaf, *node;
+        used_space_ival_t *start;
+        used_space_ival_t *cur;
         uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
 
@@ -164 +164 @@
          */
         if (area->flags & AS_AREA_WRITE) {
-                node = list_get_instance(list_first(&area->used_space.leaf_list),
-                    btree_node_t, leaf_link);
+                start = used_space_first(&area->used_space);
         } else {
-                (void) btree_search(&area->used_space, start_anon, &leaf);
-                node = btree_leaf_node_left_neighbour(&area->used_space, leaf);
-                if (!node)
-                        node = leaf;
+                /* Find first interval containing addresses >= start_anon */
+                start = used_space_find_gteq(&area->used_space, start_anon);
         }
 
@@ -177 +174 @@
          */
         mutex_lock(&area->sh_info->lock);
-        for (cur = &node->leaf_link; cur != &area->used_space.leaf_list.head;
-            cur = cur->next) {
+        cur = start;
+        while (cur != NULL) {
+                uintptr_t base = cur->page;
+                size_t count = cur->count;
                 unsigned int i;
 
-                node = list_get_instance(cur, btree_node_t, leaf_link);
-
-                for (i = 0; i < node->keys; i++) {
-                        uintptr_t base = node->key[i];
-                        size_t count = (size_t) node->value[i];
-                        unsigned int j;
+                /*
+                 * Skip read-only areas of used space that are backed
+                 * by the ELF image.
+                 */
+                if (!(area->flags & AS_AREA_WRITE))
+                        if (base >= entry->p_vaddr &&
+                            base + P2SZ(count) <= start_anon)
+                                continue;
+
+                for (i = 0; i < count; i++) {
+                        pte_t pte;
+                        bool found;
 
                         /*
-                         * Skip read-only areas of used space that are backed
-                         * by the ELF image.
+                         * Skip read-only pages that are backed by the
+                         * ELF image.
                          */
                         if (!(area->flags & AS_AREA_WRITE))
                                 if (base >= entry->p_vaddr &&
-                                    base + P2SZ(count) <= start_anon)
+                                    base + P2SZ(i + 1) <= start_anon)
                                         continue;
 
-                        for (j = 0; j < count; j++) {
-                                pte_t pte;
-                                bool found;
-
-                                /*
-                                 * Skip read-only pages that are backed by the
-                                 * ELF image.
-                                 */
-                                if (!(area->flags & AS_AREA_WRITE))
-                                        if (base >= entry->p_vaddr &&
-                                            base + P2SZ(j + 1) <= start_anon)
-                                                continue;
-
-                                page_table_lock(area->as, false);
-                                found = page_mapping_find(area->as,
-                                    base + P2SZ(j), false, &pte);
-
-                                (void) found;
-                                assert(found);
-                                assert(PTE_VALID(&pte));
-                                assert(PTE_PRESENT(&pte));
-
-                                as_pagemap_insert(&area->sh_info->pagemap,
-                                    (base + P2SZ(j)) - area->base,
-                                    PTE_GET_FRAME(&pte));
-                                page_table_unlock(area->as, false);
-
-                                pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(&pte));
-                                frame_reference_add(pfn);
-                        }
-
+                        page_table_lock(area->as, false);
+                        found = page_mapping_find(area->as,
+                            base + P2SZ(i), false, &pte);
+
+                        (void) found;
+                        assert(found);
+                        assert(PTE_VALID(&pte));
+                        assert(PTE_PRESENT(&pte));
+
+                        as_pagemap_insert(&area->sh_info->pagemap,
+                            (base + P2SZ(i)) - area->base,
+                            PTE_GET_FRAME(&pte));
+                        page_table_unlock(area->as, false);
+
+                        pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(&pte));
+                        frame_reference_add(pfn);
                 }
-        }
+
+                cur = used_space_next(cur);
+        }
+
         mutex_unlock(&area->sh_info->lock);
 }
@@ -310 +303 @@
                         page_mapping_insert(AS, upage, frame,
                             as_area_get_flags(area));
-                        if (!used_space_insert(area, upage, 1))
+                        if (!used_space_insert(&area->used_space, upage, 1))
                                 panic("Cannot insert used space.");
                         mutex_unlock(&area->sh_info->lock);
@@ -405 +398 @@
 
         page_mapping_insert(AS, upage, frame, as_area_get_flags(area));
-        if (!used_space_insert(area, upage, 1))
+        if (!used_space_insert(&area->used_space, upage, 1))
                 panic("Cannot insert used space.");