rename common to src

+ I keep starting to type src and wondering why autocomplete won't work,
  I guess src is just uncounciously a better name

1 files changed, 587 insertions, 0 deletions

diff --git a/src/mem_regions.c b/src/mem_regions.c
new file mode 100644
index 0000000..9468774
--- /dev/null
+++ b/src/mem_regions.c
@@ -0,0 +1,587 @@
+/* SPDX-License-Identifier: copyleft-next-0.3.1 */
+/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
+
+/**
+ * @file mem_regions.c
+ * Memory region handling, used by both device memory and user virtual memory
+ * subsystems.
+ */
+
+#include <kmi/mem_regions.h>
+#include <kmi/mem_nodes.h>
+#include <kmi/pmem.h>
+#include <kmi/bits.h>
+#include <kmi/mem.h>
+
+/**
+ * Readability wrapper for marking region used.
+ *
+ * @param r Region flags to set.
+ */
+#define mark_region_used(r) set_bit(r, MR_USED)
+
+/**
+ * Readability wrapper for marking region unused.
+ *
+ * @param r Region flags to clear.
+ */
+#define mark_region_unused(r) clear_bit(r, MR_USED)
+
+/* pretty major slowdown when we get to some really massive numbers, not
+ * entirely sure why. Will need to check up on this at some point, have I
+ * somehow managed to come up with a _very_ bad situation for my sp_trees?
+ *
+ * EDIT: apparently, yeah. Max depth of 106 with a million entries, interesting.
+ * I guess since in this scenario all sizes are 1, and I just shove everything
+ * to the right? Maybe?
+ *
+ * EDIT upon EDIT: yeah, when taking the start position of the region into
+ * account we get a much more sensible max depth of 39 for 5 million entries.
+ * Seems I have found a weakness in sp_trees :D
+ *
+ * Duplicate entries don't work well with any trees, I think. Good to know,
+ * maybe not even anything with sp_trees but more a weakness of binary trees in
+ * general?
+ */
+
+/**
+ * Insert free memory region.
+ *
+ * @param r Memory region root to insert \c m into.
+ * @param m Free memory region to insert.
+ * @return \c m.
+ */
+static struct mem_region *__insert_free_region(struct mem_region_root *r,
+                                               struct mem_region *m)
+{
+	struct sp_node *n = sp_root(&r->free_regions), *p = NULL;
+	vm_t start = m->start;
+	size_t size = m->end - m->start;
+	enum sp_dir d = LEFT;
+
+	m->sp_n = (struct sp_node){ 0 };
+
+	while (n) {
+		struct mem_region *t = mem_container(n);
+		size_t nsize = t->end - t->start;
+		p = n;
+
+		if (size < nsize) {
+			n = sp_left(n);
+			d = LEFT;
+		}
+
+		else if (size > nsize) {
+			n = sp_right(n);
+			d = RIGHT;
+		}
+
+		else if (start < t->start) {
+			n = sp_left(n);
+			d = LEFT;
+		}
+
+		else {
+			n = sp_right(n);
+			d = RIGHT;
+		}
+	}
+
+	if (sp_root(&r->free_regions))
+		sp_insert(&sp_root(&r->free_regions), p, &m->sp_n, d);
+	else
+		sp_root(&r->free_regions) = &m->sp_n;
+
+	return m;
+}
+
+/**
+ * Insert used memory region.
+ *
+ * @param r Memory region root to insert \c m into.
+ * @param m Memory region to insert.
+ * @return \c m.
+ */
+static struct mem_region *__insert_used_region(struct mem_region_root *r,
+                                               struct mem_region *m)
+{
+	struct sp_node *n = sp_root(&r->used_regions), *p = NULL;
+	vm_t start = m->start;
+	enum sp_dir d = LEFT;
+
+	m->sp_n = (struct sp_node){ 0 };
+
+	while (n) {
+		struct mem_region *t = mem_container(n);
+
+		p = n;
+
+		if (start < t->start) {
+			n = sp_left(n);
+			d = LEFT;
+		}
+
+		else {
+			/* we should never encounter a situation where start =
+			 * t->start */
+			n = sp_right(n);
+			d = RIGHT;
+		}
+	}
+
+	if (sp_root(&r->used_regions))
+		sp_insert(&sp_root(&r->used_regions), p, &m->sp_n, d);
+	else
+		sp_root(&r->used_regions) = &m->sp_n;
+
+	return m;
+}
+
+stat_t init_region(struct mem_region_root *r, vm_t start, size_t arena_size)
+{
+	/* convert bytes to pages */
+	start = __page(start);
+	arena_size = __page(arena_size);
+	struct mem_region *m = get_mem_node();
+	m->start = start;
+	m->end = start + arena_size;
+	__insert_free_region(r, m);
+
+	return OK;
+}
+
+/**
+ * Destroy memory region and all its children.
+ *
+ * @param n \ref sp_node of memory region to destroy.
+ */
+static void __destroy_region(struct sp_node *n)
+{
+	if (!n)
+		return;
+
+	if (sp_left(n))
+		__destroy_region(sp_left(n));
+
+	if (sp_right(n))
+		__destroy_region(sp_right(n));
+
+	struct mem_region *m = mem_container(n);
+	free_mem_node(m);
+}
+
+stat_t destroy_region(struct mem_region_root *r)
+{
+	__destroy_region(sp_root(&r->free_regions));
+	__destroy_region(sp_root(&r->used_regions));
+	/** \todo error checking? */
+	return OK;
+}
+
+/* interestingly this is now the main bottleneck :D
+ *
+ * eh, it's not a massive thing I guess, maybe the code could be a bit quicker
+ * but I mean 10 000 000 memory allocations in 20 s is good enough for now
+ * */
+struct mem_region *find_used_region(struct mem_region_root *r, vm_t start)
+{
+	/** @todo check that start is aligned to page boundary? */
+	vm_t ref = __page(start);
+	struct sp_node *n = sp_root(&r->used_regions);
+	while (n) {
+		struct mem_region *t = mem_container(n);
+		if (ref == t->start)
+			return t;
+
+		if (ref < t->start)
+			n = sp_left(n);
+		else
+			n = sp_right(n);
+	}
+
+	return 0;
+}
+
+/**
+ * Create memory region.
+ *
+ * @param start Start of region.
+ * @param end End of region.
+ * @param prev Previous region.
+ * @param next Next region.
+ * @return Created region.
+ */
+static struct mem_region *__create_region(vm_t start, vm_t end,
+                                          struct mem_region *prev,
+                                          struct mem_region *next)
+{
+	struct mem_region *m = get_mem_node();
+	m->start = start;
+	m->end = end;
+	m->prev = prev;
+	m->next = next;
+	return m;
+}
+
+/**
+ * Get first order size smaller than \c s in bytes.
+ *
+ * @param s Size to look for.
+ * @return Size of first order smaller than \c s.
+ */
+static size_t po_align(size_t s)
+{
+	for (size_t o = __mm_max_order; o > 0; --o) {
+		if (s >= order_size(o))
+			return order_size(o);
+	}
+
+	return 0;
+}
+
+struct mem_region *find_closest_used_region(struct mem_region_root *r,
+                                            vm_t start)
+{
+	struct mem_region *closest = 0;
+	size_t md = (size_t)(-1);
+	struct sp_node *n = sp_root(&r->used_regions);
+	if (!n)
+		return mem_container(sp_root(&r->free_regions));
+
+	while (n) {
+		struct mem_region *t = mem_container(n);
+		size_t d = ABS((ssize_t)start - (ssize_t)t->start);
+
+		if (d == 0) /* exact match */
+			return t;
+
+		if (d < md) { /* closest so far */
+			closest = t;
+			md = d;
+		}
+
+		if (start < t->start)
+			n = sp_left(n);
+		else
+			n = sp_right(n);
+	}
+
+	return closest;
+}
+
+/* should probably document this a bit better but in short, look for the "best"
+ * free block, meaning one that is hopefully aligned so as to allow us to later
+ * map it to higher order pages. If no block is found such that that is
+ * possible, also keep track of the smallest block that we found that the region
+ * still fits in, unaligned. If none of these criteria are met, a NULL is
+ * returned. Note that this does not check *all* possible memory blocks, only
+ * going up in increasing size so as to save time. */
+struct mem_region *find_free_region(struct mem_region_root *r, size_t size,
+                                    size_t *align)
+{
+	*align = 0;
+	size_t offset = __page(po_align(__addr(size)));
+	struct mem_region *quick_best = 0;
+	struct sp_node *n = sp_root(&r->free_regions);
+	while (n) {
+		struct mem_region *t = mem_container(n);
+		vm_t start = align_up(t->start, offset);
+
+		size_t qsize = t->end - t->start;
+		size_t bsize = t->end - start;
+
+		if (!quick_best && size <= qsize)
+			quick_best = t;
+
+		if (size <= bsize) {
+			*align = start - t->start;
+			return t;
+		}
+
+		n = sp_right(n);
+	}
+
+	return quick_best;
+}
+
+struct mem_region *find_first_region(struct mem_region_root *r)
+{
+	/* get used region with smallest address, likely also close to the start
+	 * of the linked list */
+	struct mem_region *m = find_closest_used_region(r, 0);
+	while (m->prev) {
+		m = m->prev;
+	}
+
+	return m;
+}
+
+/**
+ * Carve out new used memory region from free memory region.
+ *
+ * @param r Memory region root to work in.
+ * @param m Free memory region to carve used memory region out of.
+ * @param pages Number of base order pages to give used region.
+ * @param align Alignment of used region. In this case, start of used region
+ * @param pid Process ID to associate with region if shared. 0 if private.
+ * from start of free region.
+ * @param flags Flags of used region.
+ * @return Start address of used region.
+ */
+static vm_t __partition_region(struct mem_region_root *r, struct mem_region *m,
+                               size_t pages, size_t align, vmflags_t flags,
+                               id_t pid)
+{
+	sp_remove(&sp_root(&r->free_regions), &m->sp_n);
+
+	vm_t pre_start = m->start;
+	vm_t pre_end = pre_start + align;
+
+	vm_t start = pre_end;
+	vm_t end = start + pages;
+
+	vm_t post_start = end;
+	vm_t post_end = m->end;
+
+	if (pre_start != pre_end) {
+		struct mem_region *n =
+			__create_region(pre_start, pre_end, m->prev, m);
+		m->prev = n;
+		if (n->prev)
+			n->prev->next = n;
+
+		__insert_free_region(r, n);
+	}
+
+	if (post_start != post_end) {
+		struct mem_region *n =
+			__create_region(post_start, post_end, m, m->next);
+		m->next = n;
+		if (n->next)
+			n->next->prev = n;
+
+		__insert_free_region(r, n);
+	}
+
+	m->end = end;
+	m->start = start;
+	m->flags = flags;
+	m->pid = pid;
+	mark_region_used(m->flags);
+	__insert_used_region(r, m);
+	return __addr(start);
+}
+
+/* apparently Linux doesn't necessarily give a shit about mmap hints, so I'll
+ * just ignore them for now. Note that alloc_region should only be used when
+ * mmap is called with MAP_ANON, all other situations should be handled in some
+ * fs server */
+vm_t alloc_shared_region(struct mem_region_root *r, size_t size,
+                         size_t *actual_size,
+                         vmflags_t flags, id_t pid)
+{
+	size_t asize = align_up(size, BASE_PAGE_SIZE);
+	if (actual_size)
+		*actual_size = asize;
+
+	size_t pages = __page(asize);
+
+	/* find best fitting, alignment etc. */
+	size_t align = 0;
+	struct mem_region *m = find_free_region(r, pages, &align);
+	if (!m)
+		return 0;
+
+	return __partition_region(r, m, pages, align, flags, pid);
+}
+
+vm_t alloc_region(struct mem_region_root *r, size_t size, size_t *actual_size,
+                  vmflags_t flags)
+{
+	return alloc_shared_region(r, size, actual_size, flags, 0);
+}
+
+vm_t alloc_fixed_region(struct mem_region_root *r, vm_t start, size_t size,
+                        size_t *actual_size, vmflags_t flags)
+{
+	size_t asize = align_up(size, BASE_PAGE_SIZE);
+	if (actual_size)
+		*actual_size = asize;
+
+	size_t pages = __page(asize);
+	start = __page(start);
+
+	struct mem_region *m = find_closest_used_region(r, start);
+	if (!m)
+		return 0;
+
+	/* locate actual region where start is between the region start and end */
+	while (!((m->start <= start) && (start < m->end))) {
+		if (start > m->start)
+			m = m->next;
+		else
+			m = m->prev;
+	}
+
+	/* if region is already in use, forget it */
+	if (is_region_used(m))
+		return 0;
+
+	/* region is too small */
+	if (start + pages > m->end)
+		return 0;
+
+	/* actually start marking region used */
+	return __partition_region(r, m, pages, start - m->start, flags, 0);
+}
+
+/**
+ * Try to coalesce two adjacent memory regions, iterating left.
+ *
+ * @param r Memory region root to work in.
+ * @param m Memory region to start trying to coalesce.
+ */
+static void __try_coalesce_prev(struct mem_region_root *r, struct mem_region *m)
+{
+	while (m) {
+		if (!m || is_region_used(m))
+			return;
+
+		struct mem_region *p = m->prev;
+		if (!p || is_region_used(p))
+			return;
+
+		m->start = p->start;
+		m->prev = p->prev;
+
+		if (m->prev)
+			m->prev->next = m;
+
+		sp_remove(&sp_root(&r->free_regions), &p->sp_n);
+		free_mem_node(p);
+
+		m = m->prev;
+	}
+}
+
+/**
+ * Try to coalesce two adjacent memory region, iterating right.
+ *
+ * @param r Memory region root to work in.
+ * @param m Memory region to start trying to coalesce.
+ */
+static void __try_coalesce_next(struct mem_region_root *r, struct mem_region *m)
+{
+	while (m) {
+		if (!m || is_region_used(m))
+			return;
+
+		struct mem_region *n = m->next;
+		if (!n || is_region_used(n))
+			return;
+
+		m->end = n->end;
+		m->next = n->next;
+
+		if (m->next)
+			m->next->prev = m;
+
+		sp_remove(&sp_root(&r->free_regions), &n->sp_n);
+		free_mem_node(n);
+
+		m = m->next;
+	}
+}
+
+/**
+ * Try coalescing memory regions.
+ *
+ * @param r Memory region root to work in.
+ * @param m Memory region to start trying to coalesce.
+ */
+static void __try_coalesce_regions(struct mem_region_root *r,
+                                   struct mem_region *m)
+{
+	__try_coalesce_prev(r, m);
+	__try_coalesce_next(r, m);
+}
+
+stat_t free_region(struct mem_region_root *r, vm_t start)
+{
+	/* addr not aligned to page boundary, corrupted or incorrect pointer */
+	if (!is_aligned(start, BASE_PAGE_SIZE))
+		return ERR_ALIGN;
+
+	struct mem_region *m = find_used_region(r, start);
+	if (!m)
+		return ERR_NF;
+
+	return free_known_region(r, m);
+}
+
+stat_t free_known_region(struct mem_region_root *r, struct mem_region *m)
+{
+	sp_remove(&sp_root(&r->used_regions), &m->sp_n);
+	mark_region_unused(m->flags);
+
+	__try_coalesce_regions(r, m);
+	__insert_free_region(r, m);
+	return OK;
+}
+
+void set_alt_region_addr(struct mem_region_root *r, vm_t va, vm_t alt_va)
+{
+	struct mem_region *m = find_used_region(r, va);
+	if (!m)
+		return;
+
+	/* not shared region */
+	if (m->pid == 0)
+		return;
+
+	m->alt_va = alt_va;
+}
+
+/* assuming start is chosen to start on an aligned border, this should choose
+ * the 'optimal' fit for the mapping.
+ *
+ * NOTE: not actually optimal, this doesn't bother to go through possible
+ * permutations etc. which would be slow and I don't want to implement it.
+ */
+vm_t map_fill_region(struct vmem *b, region_callback_t *mem_handler,
+                     pm_t offset, vm_t start, size_t bytes, vmflags_t flags,
+                     void *data)
+{
+	pm_t runner = __page(start);
+	size_t pages = __pages(bytes);
+	enum mm_order top = __mm_max_order;
+
+	/* actual start might not be the same as the user specified start */
+	start = __addr(runner);
+
+	for (; pages; top--) {
+		size_t o_size = order_size(top);
+		size_t o_pages = __pages(o_size);
+
+		/* NULL does pass this check, so technically all NULL pages are
+		 * aligned, but they're caught in the while expr so this should
+		 * work even if someone tries to map NULL */
+		if (!is_aligned(runner, o_pages))
+			continue;
+
+		while (pages >= o_pages) {
+			stat_t res = mem_handler(b, &offset, __addr(runner),
+			                         flags, top, data);
+			if (res > 0)
+				break;
+
+			if (res < 0)
+				return 0;
+
+			pages -= o_pages;
+			runner += o_pages;
+		}
+	}
+
+	return start;
+}