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@

3 files changed, 126 insertions, 39 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
diff --git a/sys/dev/pci/drm/include/linux/mm.h b/sys/dev/pci/drm/include/linux/mm.h
index f7d84207793..6c3a0c640d5 100644
--- a/sys/dev/pci/drm/include/linux/mm.h
+++ b/sys/dev/pci/drm/include/linux/mm.h
@@ -30,38 +30,31 @@
 #define PFN_DOWN(x)		((x) >> PAGE_SHIFT)
 #define PFN_PHYS(x)		((x) << PAGE_SHIFT)
 
-#define is_vmalloc_addr(ptr)	true
+bool is_vmalloc_addr(const void *);
 
-static inline void *
-kvmalloc(size_t size, gfp_t flags)
-{
-	return malloc(size, M_DRM, flags);
-}
+void *kvmalloc(size_t, gfp_t);
+void kvfree(const void *);
 
 static inline void *
-kvmalloc_array(size_t n, size_t size, int flags)
+kvmalloc_array(size_t n, size_t size, gfp_t flags)
 {
 	if (n != 0 && SIZE_MAX / n < size)
 		return NULL;
-	return malloc(n * size, M_DRM, flags);
+	return kvmalloc(n * size, flags);
 }
 
 static inline void *
-kvcalloc(size_t n, size_t size, int flags)
+kvcalloc(size_t n, size_t size, gfp_t flags)
 {
-	return kvmalloc_array(n, size, flags | M_ZERO);
+	if (n != 0 && SIZE_MAX / n < size)
+		return NULL;
+	return kvmalloc(n * size, flags | M_ZERO);
 }
 
 static inline void *
-kvzalloc(size_t size, int flags)
-{
-	return malloc(size, M_DRM, flags | M_ZERO);
-}
-
-static inline void
-kvfree(const void *objp)
+kvzalloc(size_t size, gfp_t flags)
 {
-	free((void *)objp, M_DRM, 0);
+	return kvmalloc(size, flags | M_ZERO);
 }
 
 static inline long
diff --git a/sys/dev/pci/drm/include/linux/vmalloc.h b/sys/dev/pci/drm/include/linux/vmalloc.h
index 7daa7bea5bd..fd6cc54b7db 100644
--- a/sys/dev/pci/drm/include/linux/vmalloc.h
+++ b/sys/dev/pci/drm/include/linux/vmalloc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmalloc.h,v 1.1 2019/04/14 10:14:53 jsg Exp $	*/
+/*	$OpenBSD: vmalloc.h,v 1.2 2021/01/08 23:02:09 kettenis Exp $	*/
 /*
  * Copyright (c) 2013, 2014, 2015 Mark Kettenis
  *
@@ -25,25 +25,10 @@
 #include <linux/overflow.h>
 
 void	*vmap(struct vm_page **, unsigned int, unsigned long, pgprot_t);
-void	 vunmap(void *, size_t);
-
-static inline void *
-vmalloc(unsigned long size)
-{
-	return malloc(size, M_DRM, M_WAITOK | M_CANFAIL);
-}
-
-static inline void *
-vzalloc(unsigned long size)
-{
-	return malloc(size, M_DRM, M_WAITOK | M_CANFAIL | M_ZERO);
-}
-
-static inline void
-vfree(void *objp)
-{
-	free(objp, M_DRM, 0);
-}
+void	vunmap(void *, size_t);
 
+void	*vmalloc(unsigned long);
+void	*vzalloc(unsigned long);
+void	vfree(const void *);
 
 #endif