Bring the emulated Linux memory allocation interfaces more in line with

what Linux does.  Let vmalloc() use km_alloc(9) instead of malloc(9) and
let kvmalloc() only use malloc(9) for small (less than a page) allocations
and atomic allocations.  This should reduce the pressure on the
"interrupt-safe" map.

ok jsg@

1 files changed, 110 insertions, 1 deletions

diff --git a/sys/dev/pci/drm/drm_linux.c b/sys/dev/pci/drm/drm_linux.c
index d01db47d517..a893c4de89b 100644
--- a/sys/dev/pci/drm/drm_linux.c
+++ b/sys/dev/pci/drm/drm_linux.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: drm_linux.c,v 1.74 2020/12/31 06:31:55 jsg Exp $	*/
+/*	$OpenBSD: drm_linux.c,v 1.75 2021/01/08 23:02:09 kettenis Exp $	*/
 /*
  * Copyright (c) 2013 Jonathan Gray <jsg@openbsd.org>
  * Copyright (c) 2015, 2016 Mark Kettenis <kettenis@openbsd.org>
@@ -430,6 +430,111 @@ dmi_check_system(const struct dmi_system_id *sysid)
 	return (num);
 }
 
+struct vmalloc_entry {
+	const void	*addr;
+	size_t		size;
+	RBT_ENTRY(vmalloc_entry) vmalloc_node;
+};
+
+struct pool vmalloc_pool;
+RBT_HEAD(vmalloc_tree, vmalloc_entry) vmalloc_tree;
+
+RBT_PROTOTYPE(vmalloc_tree, vmalloc_entry, vmalloc_node, vmalloc_compare);
+
+static inline int
+vmalloc_compare(const struct vmalloc_entry *a, const struct vmalloc_entry *b)
+{
+	vaddr_t va = (vaddr_t)a->addr;
+	vaddr_t vb = (vaddr_t)b->addr;
+
+	return va < vb ? -1 : va > vb;
+}
+
+RBT_GENERATE(vmalloc_tree, vmalloc_entry, vmalloc_node, vmalloc_compare);
+
+bool
+is_vmalloc_addr(const void *addr)
+{
+	struct vmalloc_entry key;
+	struct vmalloc_entry *entry;
+
+	key.addr = addr;
+	entry = RBT_FIND(vmalloc_tree, &vmalloc_tree, &key);
+	return (entry != NULL);
+}
+
+void *
+vmalloc(unsigned long size)
+{
+	struct vmalloc_entry *entry;
+	void *addr;
+
+	size = round_page(size);
+	addr = km_alloc(size, &kv_any, &kp_dirty, &kd_waitok);
+	if (addr) {
+		entry = pool_get(&vmalloc_pool, PR_WAITOK);
+		entry->addr = addr;
+		entry->size = size;
+		RBT_INSERT(vmalloc_tree, &vmalloc_tree, entry);
+	}
+
+	return addr;
+}
+
+void *
+vzalloc(unsigned long size)
+{
+	struct vmalloc_entry *entry;
+	void *addr;
+
+	size = round_page(size);
+	addr = km_alloc(size, &kv_any, &kp_zero, &kd_waitok);
+	if (addr) {
+		entry = pool_get(&vmalloc_pool, PR_WAITOK);
+		entry->addr = addr;
+		entry->size = size;
+		RBT_INSERT(vmalloc_tree, &vmalloc_tree, entry);
+	}
+
+	return addr;
+}
+
+void
+vfree(const void *addr)
+{
+	struct vmalloc_entry key;
+	struct vmalloc_entry *entry;
+
+	key.addr = addr;
+	entry = RBT_FIND(vmalloc_tree, &vmalloc_tree, &key);
+	if (entry == NULL)
+		panic("%s: non vmalloced addr %p", __func__, addr);
+
+	RBT_REMOVE(vmalloc_tree, &vmalloc_tree, entry);
+	km_free((void *)addr, entry->size, &kv_any, &kp_dirty);
+	pool_put(&vmalloc_pool, entry);
+}
+
+void *
+kvmalloc(size_t size, gfp_t flags)
+{
+	if ((flags & M_NOWAIT) || size < PAGE_SIZE)
+		return malloc(size, M_DRM, flags);
+	if (flags & M_ZERO)
+		return vzalloc(size);
+	else
+		return vmalloc(size);
+}
+
+void
+kvfree(const void *addr)
+{
+	if (is_vmalloc_addr(addr))
+		vfree(addr);
+	else
+		free((void *)addr, M_DRM, 0);
+}
+
 struct vm_page *
 alloc_pages(unsigned int gfp_mask, unsigned int order)
 {
@@ -1939,6 +2044,10 @@ drm_linux_init(void)
 
 	pool_init(&idr_pool, sizeof(struct idr_entry), 0, IPL_TTY, 0,
 	    "idrpl", NULL);
+
+	pool_init(&vmalloc_pool, sizeof(struct vmalloc_entry), 0, IPL_NONE, 0,
+	    "vmallocpl", NULL);
+	RBT_INIT(vmalloc_tree, &vmalloc_tree);
 }
 
 void