[PATCH v2 0/3] introduce static_vm for ARM-specific static mapped area

[PATCH v2 0/3] introduce static_vm for ARM-specific static mapped area

[Joonsoo Kim]

In current implementation, we used ARM-specific flag, that is,
VM_ARM_STATIC_MAPPING, for distinguishing ARM specific static mapped area.
The purpose of static mapped area is to re-use static mapped area when
entire physical address range of the ioremap request can be covered
by this area.

This implementation causes needless overhead for some cases.
For example, assume that there is only one static mapped area and
vmlist has 300 areas. Every time we call ioremap, we check 300 areas for
deciding whether it is matched or not. Moreover, even if there is
no static mapped area and vmlist has 300 areas, every time we call
ioremap, we check 300 areas in now.

If we construct a extra list for static mapped area, we can eliminate
above mentioned overhead.
With a extra list, if there is one static mapped area,
we just check only one area and proceed next operation quickly.

In fact, it is not a critical problem, because ioremap is not frequently
used. But reducing overhead is better idea.

Another reason for doing this work is for removing architecture dependency
on vmalloc layer. I think that vmlist and vmlist_lock is internal data
structure for vmalloc layer. Some codes for debugging and stat inevitably
use vmlist and vmlist_lock. But it is preferable that they are used
as least as possible in outside of vmalloc.c

Changelog
v1->v2: 
  [2/3]: patch description is improved.
  Rebased on v3.7-rc7

Joonsoo Kim (3):
  ARM: vmregion: remove vmregion code entirely
  ARM: static_vm: introduce an infrastructure for static mapped area
  ARM: mm: use static_vm for managing static mapped areas

 arch/arm/include/asm/mach/static_vm.h |   51 ++++++++
 arch/arm/mm/Makefile                  |    2 +-
 arch/arm/mm/ioremap.c                 |   69 ++++-------
 arch/arm/mm/mm.h                      |   10 --
 arch/arm/mm/mmu.c                     |   55 +++++----
 arch/arm/mm/static_vm.c               |   97 ++++++++++++++++
 arch/arm/mm/vmregion.c                |  205 ---------------------------------
 arch/arm/mm/vmregion.h                |   31 -----
 8 files changed, 208 insertions(+), 312 deletions(-)
 create mode 100644 arch/arm/include/asm/mach/static_vm.h
 create mode 100644 arch/arm/mm/static_vm.c
 delete mode 100644 arch/arm/mm/vmregion.c
 delete mode 100644 arch/arm/mm/vmregion.h

-- 
1.7.9.5

[PATCH v2 1/3] ARM: vmregion: remove vmregion code entirely

[Joonsoo Kim]

Now, there is no user for vmregion.
So remove it.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>

diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 8a9c4cb..4e333fa 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -6,7 +6,7 @@ obj-y				:= dma-mapping.o extable.o fault.o init.o \
 				   iomap.o
 
 obj-$(CONFIG_MMU)		+= fault-armv.o flush.o idmap.o ioremap.o \
-				   mmap.o pgd.o mmu.o vmregion.o
+				   mmap.o pgd.o mmu.o
 
 ifneq ($(CONFIG_MMU),y)
 obj-y				+= nommu.o
diff --git a/arch/arm/mm/vmregion.c b/arch/arm/mm/vmregion.c
deleted file mode 100644
index a631016..0000000
--- a/arch/arm/mm/vmregion.c
+++ /dev/null
@@ -1,205 +0,0 @@
-#include <linux/fs.h>
-#include <linux/spinlock.h>
-#include <linux/list.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/slab.h>
-
-#include "vmregion.h"
-
-/*
- * VM region handling support.
- *
- * This should become something generic, handling VM region allocations for
- * vmalloc and similar (ioremap, module space, etc).
- *
- * I envisage vmalloc()'s supporting vm_struct becoming:
- *
- *  struct vm_struct {
- *    struct vmregion	region;
- *    unsigned long	flags;
- *    struct page	**pages;
- *    unsigned int	nr_pages;
- *    unsigned long	phys_addr;
- *  };
- *
- * get_vm_area() would then call vmregion_alloc with an appropriate
- * struct vmregion head (eg):
- *
- *  struct vmregion vmalloc_head = {
- *	.vm_list	= LIST_HEAD_INIT(vmalloc_head.vm_list),
- *	.vm_start	= VMALLOC_START,
- *	.vm_end		= VMALLOC_END,
- *  };
- *
- * However, vmalloc_head.vm_start is variable (typically, it is dependent on
- * the amount of RAM found at boot time.)  I would imagine that get_vm_area()
- * would have to initialise this each time prior to calling vmregion_alloc().
- */
-
-struct arm_vmregion *
-arm_vmregion_alloc(struct arm_vmregion_head *head, size_t align,
-		   size_t size, gfp_t gfp, const void *caller)
-{
-	unsigned long start = head->vm_start, addr = head->vm_end;
-	unsigned long flags;
-	struct arm_vmregion *c, *new;
-
-	if (head->vm_end - head->vm_start < size) {
-		printk(KERN_WARNING "%s: allocation too big (requested %#x)\n",
-			__func__, size);
-		goto out;
-	}
-
-	new = kmalloc(sizeof(struct arm_vmregion), gfp);
-	if (!new)
-		goto out;
-
-	new->caller = caller;
-
-	spin_lock_irqsave(&head->vm_lock, flags);
-
-	addr = rounddown(addr - size, align);
-	list_for_each_entry_reverse(c, &head->vm_list, vm_list) {
-		if (addr >= c->vm_end)
-			goto found;
-		addr = rounddown(c->vm_start - size, align);
-		if (addr < start)
-			goto nospc;
-	}
-
- found:
-	/*
-	 * Insert this entry after the one we found.
-	 */
-	list_add(&new->vm_list, &c->vm_list);
-	new->vm_start = addr;
-	new->vm_end = addr + size;
-	new->vm_active = 1;
-
-	spin_unlock_irqrestore(&head->vm_lock, flags);
-	return new;
-
- nospc:
-	spin_unlock_irqrestore(&head->vm_lock, flags);
-	kfree(new);
- out:
-	return NULL;
-}
-
-static struct arm_vmregion *__arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
-{
-	struct arm_vmregion *c;
-
-	list_for_each_entry(c, &head->vm_list, vm_list) {
-		if (c->vm_active && c->vm_start == addr)
-			goto out;
-	}
-	c = NULL;
- out:
-	return c;
-}
-
-struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
-{
-	struct arm_vmregion *c;
-	unsigned long flags;
-
-	spin_lock_irqsave(&head->vm_lock, flags);
-	c = __arm_vmregion_find(head, addr);
-	spin_unlock_irqrestore(&head->vm_lock, flags);
-	return c;
-}
-
-struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *head, unsigned long addr)
-{
-	struct arm_vmregion *c;
-	unsigned long flags;
-
-	spin_lock_irqsave(&head->vm_lock, flags);
-	c = __arm_vmregion_find(head, addr);
-	if (c)
-		c->vm_active = 0;
-	spin_unlock_irqrestore(&head->vm_lock, flags);
-	return c;
-}
-
-void arm_vmregion_free(struct arm_vmregion_head *head, struct arm_vmregion *c)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&head->vm_lock, flags);
-	list_del(&c->vm_list);
-	spin_unlock_irqrestore(&head->vm_lock, flags);
-
-	kfree(c);
-}
-
-#ifdef CONFIG_PROC_FS
-static int arm_vmregion_show(struct seq_file *m, void *p)
-{
-	struct arm_vmregion *c = list_entry(p, struct arm_vmregion, vm_list);
-
-	seq_printf(m, "0x%08lx-0x%08lx %7lu", c->vm_start, c->vm_end,
-		c->vm_end - c->vm_start);
-	if (c->caller)
-		seq_printf(m, " %pS", (void *)c->caller);
-	seq_putc(m, '\n');
-	return 0;
-}
-
-static void *arm_vmregion_start(struct seq_file *m, loff_t *pos)
-{
-	struct arm_vmregion_head *h = m->private;
-	spin_lock_irq(&h->vm_lock);
-	return seq_list_start(&h->vm_list, *pos);
-}
-
-static void *arm_vmregion_next(struct seq_file *m, void *p, loff_t *pos)
-{
-	struct arm_vmregion_head *h = m->private;
-	return seq_list_next(p, &h->vm_list, pos);
-}
-
-static void arm_vmregion_stop(struct seq_file *m, void *p)
-{
-	struct arm_vmregion_head *h = m->private;
-	spin_unlock_irq(&h->vm_lock);
-}
-
-static const struct seq_operations arm_vmregion_ops = {
-	.start	= arm_vmregion_start,
-	.stop	= arm_vmregion_stop,
-	.next	= arm_vmregion_next,
-	.show	= arm_vmregion_show,
-};
-
-static int arm_vmregion_open(struct inode *inode, struct file *file)
-{
-	struct arm_vmregion_head *h = PDE(inode)->data;
-	int ret = seq_open(file, &arm_vmregion_ops);
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-		m->private = h;
-	}
-	return ret;
-}
-
-static const struct file_operations arm_vmregion_fops = {
-	.open	= arm_vmregion_open,
-	.read	= seq_read,
-	.llseek	= seq_lseek,
-	.release = seq_release,
-};
-
-int arm_vmregion_create_proc(const char *path, struct arm_vmregion_head *h)
-{
-	proc_create_data(path, S_IRUSR, NULL, &arm_vmregion_fops, h);
-	return 0;
-}
-#else
-int arm_vmregion_create_proc(const char *path, struct arm_vmregion_head *h)
-{
-	return 0;
-}
-#endif
diff --git a/arch/arm/mm/vmregion.h b/arch/arm/mm/vmregion.h
deleted file mode 100644
index 0f5a5f2..0000000
--- a/arch/arm/mm/vmregion.h
+++ /dev/null
@@ -1,31 +0,0 @@
-#ifndef VMREGION_H
-#define VMREGION_H
-
-#include <linux/spinlock.h>
-#include <linux/list.h>
-
-struct page;
-
-struct arm_vmregion_head {
-	spinlock_t		vm_lock;
-	struct list_head	vm_list;
-	unsigned long		vm_start;
-	unsigned long		vm_end;
-};
-
-struct arm_vmregion {
-	struct list_head	vm_list;
-	unsigned long		vm_start;
-	unsigned long		vm_end;
-	int			vm_active;
-	const void		*caller;
-};
-
-struct arm_vmregion *arm_vmregion_alloc(struct arm_vmregion_head *, size_t, size_t, gfp_t, const void *);
-struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *, unsigned long);
-struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *, unsigned long);
-void arm_vmregion_free(struct arm_vmregion_head *, struct arm_vmregion *);
-
-int arm_vmregion_create_proc(const char *, struct arm_vmregion_head *);
-
-#endif
-- 
1.7.9.5

[PATCH v2 2/3] ARM: static_vm: introduce an infrastructure for static mapped area

[Joonsoo Kim]

In current implementation, we used ARM-specific flag, that is,
VM_ARM_STATIC_MAPPING, for distinguishing ARM specific static mapped area.
The purpose of static mapped area is to re-use static mapped area when
entire physical address range of the ioremap request can be covered
by this area.

This implementation causes needless overhead for some cases.
For example, assume that there is only one static mapped area and
vmlist has 300 areas. Every time we call ioremap, we check 300 areas for
deciding whether it is matched or not. Moreover, even if there is
no static mapped area and vmlist has 300 areas, every time we call
ioremap, we check 300 areas in now.

If we construct a extra list for static mapped area, we can eliminate
above mentioned overhead.
With a extra list, if there is one static mapped area,
we just check only one area and proceed next operation quickly.

In fact, it is not a critical problem, because ioremap is not frequently
used. But reducing overhead is better idea.

Another reason for doing this work is for removing architecture dependency
on vmalloc layer. I think that vmlist and vmlist_lock is internal data
structure for vmalloc layer. Some codes for debugging and stat inevitably
use vmlist and vmlist_lock. But it is preferable that they are used
as least as possible in outside of vmalloc.c

Now, I introduce an ARM-specific infrastructure for static mapped area. In
the following patch, we will use this and resolve above mentioned problem.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>

diff --git a/arch/arm/include/asm/mach/static_vm.h b/arch/arm/include/asm/mach/static_vm.h
new file mode 100644
index 0000000..1bb6604
--- /dev/null
+++ b/arch/arm/include/asm/mach/static_vm.h
@@ -0,0 +1,45 @@
+/*
+ * arch/arm/include/asm/mach/static_vm.h
+ *
+ * Copyright (C) 2012 LG Electronics, Joonsoo Kim <js1304@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _ASM_MACH_STATIC_VM_H
+#define _ASM_MACH_STATIC_VM_H
+
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+
+struct static_vm {
+	struct static_vm	*next;
+	void			*vaddr;
+	unsigned long		size;
+	unsigned long		flags;
+	phys_addr_t		paddr;
+	const void		*caller;
+};
+
+extern struct static_vm *static_vmlist;
+extern spinlock_t static_vmlist_lock;
+
+extern struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
+			size_t size, unsigned long flags);
+extern struct static_vm *find_static_vm_vaddr(void *vaddr, unsigned long flags);
+extern void init_static_vm(struct static_vm *static_vm,
+			struct vm_struct *vm, unsigned long flags);
+extern void insert_static_vm(struct static_vm *vm);
+
+#endif /* _ASM_MACH_STATIC_VM_H */
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 4e333fa..57b329a 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -6,7 +6,7 @@ obj-y				:= dma-mapping.o extable.o fault.o init.o \
 				   iomap.o
 
 obj-$(CONFIG_MMU)		+= fault-armv.o flush.o idmap.o ioremap.o \
-				   mmap.o pgd.o mmu.o
+				   mmap.o pgd.o mmu.o static_vm.o
 
 ifneq ($(CONFIG_MMU),y)
 obj-y				+= nommu.o
diff --git a/arch/arm/mm/static_vm.c b/arch/arm/mm/static_vm.c
new file mode 100644
index 0000000..d7677cf
--- /dev/null
+++ b/arch/arm/mm/static_vm.c
@@ -0,0 +1,97 @@
+/*
+ * arch/arm/mm/static_vm.c
+ *
+ * Copyright (C) 2012 LG Electronics, Joonsoo Kim <js1304@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/spinlock.h>
+
+#include <asm/mach/static_vm.h>
+
+struct static_vm *static_vmlist;
+DEFINE_SPINLOCK(static_vmlist_lock);
+
+struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
+			size_t size, unsigned long flags)
+{
+	struct static_vm *area;
+
+	spin_lock(&static_vmlist_lock);
+	for (area = static_vmlist; area; area = area->next) {
+		if ((area->flags & flags) != flags)
+			continue;
+
+		if (area->paddr > paddr ||
+			paddr + size - 1 > area->paddr + area->size - 1)
+			continue;
+
+		spin_unlock(&static_vmlist_lock);
+		return area;
+	}
+	spin_unlock(&static_vmlist_lock);
+
+	return NULL;
+}
+
+struct static_vm *find_static_vm_vaddr(void *vaddr, unsigned long flags)
+{
+	struct static_vm *area;
+
+	spin_lock(&static_vmlist_lock);
+	for (area = static_vmlist; area; area = area->next) {
+		/* static_vmlist is ascending order */
+		if (area->vaddr > vaddr)
+			break;
+
+		if ((area->flags & flags) != flags)
+			continue;
+
+		if (area->vaddr <= vaddr && area->vaddr + area->size > vaddr) {
+			spin_unlock(&static_vmlist_lock);
+			return area;
+		}
+	}
+	spin_unlock(&static_vmlist_lock);
+
+	return NULL;
+}
+
+void init_static_vm(struct static_vm *static_vm,
+				struct vm_struct *vm, unsigned long flags)
+{
+	static_vm->vaddr = vm->addr;
+	static_vm->size = vm->size;
+	static_vm->paddr = vm->phys_addr;
+	static_vm->caller = vm->caller;
+	static_vm->flags = flags;
+}
+
+void insert_static_vm(struct static_vm *vm)
+{
+	struct static_vm *tmp, **p;
+
+	spin_lock(&static_vmlist_lock);
+	for (p = &static_vmlist; (tmp = *p) != NULL; p = &tmp->next) {
+		if (tmp->vaddr >= vm->vaddr) {
+			BUG_ON(tmp->vaddr < vm->vaddr + vm->size);
+			break;
+		} else
+			BUG_ON(tmp->vaddr + tmp->size > vm->vaddr);
+	}
+	vm->next = *p;
+	*p = vm;
+	spin_unlock(&static_vmlist_lock);
+}
-- 
1.7.9.5

[PATCH v2 3/3] ARM: mm: use static_vm for managing static mapped areas

[Joonsoo Kim]

A static mapped area is ARM-specific, so it is better not to use
generic vmalloc data structure, that is, vmlist and vmlist_lock
for managing static mapped area. And it causes some needless overhead and
reducing this overhead is better idea.

Now, we have newly introduced static_vm infrastructure.
With it, we don't need to iterate all mapped areas. Instead, we just
iterate static mapped areas. It helps to reduce an overhead of finding
matched area. And architecture dependency on vmalloc layer is removed,
so it will help to maintainability for vmalloc layer.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>

diff --git a/arch/arm/include/asm/mach/static_vm.h b/arch/arm/include/asm/mach/static_vm.h
index 1bb6604..0d9c685 100644
--- a/arch/arm/include/asm/mach/static_vm.h
+++ b/arch/arm/include/asm/mach/static_vm.h
@@ -32,6 +32,12 @@ struct static_vm {
 	const void		*caller;
 };
 
+#define STATIC_VM_MEM		0x00000001
+#define STATIC_VM_EMPTY		0x00000002
+
+/* mtype should be less than 28 */
+#define STATIC_VM_MTYPE(mt)	(1UL << ((mt) + 4))
+
 extern struct static_vm *static_vmlist;
 extern spinlock_t static_vmlist_lock;
 
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 5dcc2fd..b7f3c27 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -36,6 +36,7 @@
 #include <asm/system_info.h>
 
 #include <asm/mach/map.h>
+#include <asm/mach/static_vm.h>
 #include <asm/mach/pci.h>
 #include "mm.h"
 
@@ -197,7 +198,8 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
 	const struct mem_type *type;
 	int err;
 	unsigned long addr;
- 	struct vm_struct * area;
+	struct vm_struct *area;
+	phys_addr_t paddr = __pfn_to_phys(pfn);
 
 #ifndef CONFIG_ARM_LPAE
 	/*
@@ -219,24 +221,17 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
 	/*
 	 * Try to reuse one of the static mapping whenever possible.
 	 */
-	read_lock(&vmlist_lock);
-	for (area = vmlist; area; area = area->next) {
-		if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000))
-			break;
-		if (!(area->flags & VM_ARM_STATIC_MAPPING))
-			continue;
-		if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
-			continue;
-		if (__phys_to_pfn(area->phys_addr) > pfn ||
-		    __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1)
-			continue;
-		/* we can drop the lock here as we know *area is static */
-		read_unlock(&vmlist_lock);
-		addr = (unsigned long)area->addr;
-		addr += __pfn_to_phys(pfn) - area->phys_addr;
-		return (void __iomem *) (offset + addr);
+	if (size && !((sizeof(phys_addr_t) == 4 && pfn >= 0x100000))) {
+		struct static_vm *static_vm;
+
+		static_vm = find_static_vm_paddr(__pfn_to_phys(pfn), size,
+				STATIC_VM_MEM | STATIC_VM_MTYPE(mtype));
+		if (static_vm) {
+			addr = (unsigned long)static_vm->vaddr;
+			addr += paddr - static_vm->paddr;
+			return (void __iomem *) (offset + addr);
+		}
 	}
-	read_unlock(&vmlist_lock);
 
 	/*
 	 * Don't allow RAM to be mapped - this causes problems with ARMv6+
@@ -248,7 +243,7 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
  	if (!area)
  		return NULL;
  	addr = (unsigned long)area->addr;
-	area->phys_addr = __pfn_to_phys(pfn);
+	area->phys_addr = paddr;
 
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 	if (DOMAIN_IO == 0 &&
@@ -346,34 +341,20 @@ __arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached)
 void __iounmap(volatile void __iomem *io_addr)
 {
 	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
-	struct vm_struct *vm;
-
-	read_lock(&vmlist_lock);
-	for (vm = vmlist; vm; vm = vm->next) {
-		if (vm->addr > addr)
-			break;
-		if (!(vm->flags & VM_IOREMAP))
-			continue;
-		/* If this is a static mapping we must leave it alone */
-		if ((vm->flags & VM_ARM_STATIC_MAPPING) &&
-		    (vm->addr <= addr) && (vm->addr + vm->size > addr)) {
-			read_unlock(&vmlist_lock);
-			return;
-		}
+	struct static_vm *static_vm;
+
+	static_vm = find_static_vm_vaddr(addr, STATIC_VM_MEM);
+	if (static_vm)
+		return;
+
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
-		/*
-		 * If this is a section based mapping we need to handle it
-		 * specially as the VM subsystem does not know how to handle
-		 * such a beast.
-		 */
-		if ((vm->addr == addr) &&
-		    (vm->flags & VM_ARM_SECTION_MAPPING)) {
+	{
+		struct vm_struct *vm;
+		vm = find_vm_area(addr);
+		if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
 			unmap_area_sections((unsigned long)vm->addr, vm->size);
-			break;
-		}
-#endif
 	}
-	read_unlock(&vmlist_lock);
+#endif
 
 	vunmap(addr);
 }
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index a8ee92d..3ae75e5 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -52,16 +52,6 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page
 /* (super)section-mapped I/O regions used by ioremap()/iounmap() */
 #define VM_ARM_SECTION_MAPPING	0x80000000
 
-/* permanent static mappings from iotable_init() */
-#define VM_ARM_STATIC_MAPPING	0x40000000
-
-/* empty mapping */
-#define VM_ARM_EMPTY_MAPPING	0x20000000
-
-/* mapping type (attributes) for permanent static mappings */
-#define VM_ARM_MTYPE(mt)		((mt) << 20)
-#define VM_ARM_MTYPE_MASK	(0x1f << 20)
-
 /* consistent regions used by dma_alloc_attrs() */
 #define VM_ARM_DMA_CONSISTENT	0x20000000
 
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 941dfb9..6c154c1 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -31,6 +31,7 @@
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
+#include <asm/mach/static_vm.h>
 #include <asm/mach/pci.h>
 
 #include "mm.h"
@@ -757,21 +758,28 @@ void __init iotable_init(struct map_desc *io_desc, int nr)
 {
 	struct map_desc *md;
 	struct vm_struct *vm;
+	struct static_vm *static_vm;
 
 	if (!nr)
 		return;
 
 	vm = early_alloc_aligned(sizeof(*vm) * nr, __alignof__(*vm));
+	static_vm = early_alloc_aligned(sizeof(*static_vm) * nr,
+						__alignof__(*static_vm));
 
 	for (md = io_desc; nr; md++, nr--) {
 		create_mapping(md);
+
 		vm->addr = (void *)(md->virtual & PAGE_MASK);
 		vm->size = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
 		vm->phys_addr = __pfn_to_phys(md->pfn);
-		vm->flags = VM_IOREMAP | VM_ARM_STATIC_MAPPING;
-		vm->flags |= VM_ARM_MTYPE(md->type);
+		vm->flags = VM_IOREMAP;
 		vm->caller = iotable_init;
+
+		init_static_vm(static_vm, vm, STATIC_VM_MEM |
+						STATIC_VM_MTYPE(md->type));
 		vm_area_add_early(vm++);
+		insert_static_vm(static_vm++);
 	}
 }
 
@@ -779,13 +787,20 @@ void __init vm_reserve_area_early(unsigned long addr, unsigned long size,
 				  void *caller)
 {
 	struct vm_struct *vm;
+	struct static_vm *static_vm;
 
 	vm = early_alloc_aligned(sizeof(*vm), __alignof__(*vm));
+	static_vm = early_alloc_aligned(sizeof(*static_vm),
+					__alignof__(*static_vm));
+
 	vm->addr = (void *)addr;
 	vm->size = size;
-	vm->flags = VM_IOREMAP | VM_ARM_EMPTY_MAPPING;
+	vm->flags = VM_IOREMAP;
 	vm->caller = caller;
+
+	init_static_vm(static_vm, vm, STATIC_VM_EMPTY);
 	vm_area_add_early(vm);
+	insert_static_vm(static_vm);
 }
 
 #ifndef CONFIG_ARM_LPAE
@@ -810,15 +825,19 @@ static void __init pmd_empty_section_gap(unsigned long addr)
 
 static void __init fill_pmd_gaps(void)
 {
-	struct vm_struct *vm;
+	struct static_vm *area;
 	unsigned long addr, next = 0;
 	pmd_t *pmd;
 
-	/* we're still single threaded hence no lock needed here */
-	for (vm = vmlist; vm; vm = vm->next) {
-		if (!(vm->flags & (VM_ARM_STATIC_MAPPING | VM_ARM_EMPTY_MAPPING)))
-			continue;
-		addr = (unsigned long)vm->addr;
+	/*
+	 * We should not take a lock here, because pmd_empty_section_gap()
+	 * invokes vm_reserve_area_early(), and then it call insert_static_vm()
+	 * which try to take a lock.
+	 * We're still single thread, so traverse whole list without a lock
+	 * is safe for now. And inserting new entry is also safe.
+	 */
+	for (area = static_vmlist; area; area = area->next) {
+		addr = (unsigned long)area->vaddr;
 		if (addr < next)
 			continue;
 
@@ -838,7 +857,7 @@ static void __init fill_pmd_gaps(void)
 		 * If so and the second section entry for this PMD is empty
 		 * then we block the corresponding virtual address.
 		 */
-		addr += vm->size;
+		addr += area->size;
 		if ((addr & ~PMD_MASK) == SECTION_SIZE) {
 			pmd = pmd_off_k(addr) + 1;
 			if (pmd_none(*pmd))
@@ -857,19 +876,13 @@ static void __init fill_pmd_gaps(void)
 #if defined(CONFIG_PCI) && !defined(CONFIG_NEED_MACH_IO_H)
 static void __init pci_reserve_io(void)
 {
-	struct vm_struct *vm;
-	unsigned long addr;
+	struct static_vm *static_vm;
 
-	/* we're still single threaded hence no lock needed here */
-	for (vm = vmlist; vm; vm = vm->next) {
-		if (!(vm->flags & VM_ARM_STATIC_MAPPING))
-			continue;
-		addr = (unsigned long)vm->addr;
-		addr &= ~(SZ_2M - 1);
-		if (addr == PCI_IO_VIRT_BASE)
-			return;
+	static_vm = find_static_vm_vaddr((void *)PCI_IO_VIRT_BASE,
+						STATIC_VM_MEM);
+	if (static_vm)
+		return;
 
-	}
 	vm_reserve_area_early(PCI_IO_VIRT_BASE, SZ_2M, pci_reserve_io);
 }
 #else
-- 
1.7.9.5

Re: [PATCH v2 0/3] introduce static_vm for ARM-specific static mapped area

[JoonSoo Kim]

2012/11/28 Joonsoo Kim <js1304@gmail.com>:
> In current implementation, we used ARM-specific flag, that is,
> VM_ARM_STATIC_MAPPING, for distinguishing ARM specific static mapped area.
> The purpose of static mapped area is to re-use static mapped area when
> entire physical address range of the ioremap request can be covered
> by this area.
>
> This implementation causes needless overhead for some cases.
> For example, assume that there is only one static mapped area and
> vmlist has 300 areas. Every time we call ioremap, we check 300 areas for
> deciding whether it is matched or not. Moreover, even if there is
> no static mapped area and vmlist has 300 areas, every time we call
> ioremap, we check 300 areas in now.
>
> If we construct a extra list for static mapped area, we can eliminate
> above mentioned overhead.
> With a extra list, if there is one static mapped area,
> we just check only one area and proceed next operation quickly.
>
> In fact, it is not a critical problem, because ioremap is not frequently
> used. But reducing overhead is better idea.
>
> Another reason for doing this work is for removing architecture dependency
> on vmalloc layer. I think that vmlist and vmlist_lock is internal data
> structure for vmalloc layer. Some codes for debugging and stat inevitably
> use vmlist and vmlist_lock. But it is preferable that they are used
> as least as possible in outside of vmalloc.c
>
> Changelog
> v1->v2:
>   [2/3]: patch description is improved.
>   Rebased on v3.7-rc7
>
> Joonsoo Kim (3):
>   ARM: vmregion: remove vmregion code entirely
>   ARM: static_vm: introduce an infrastructure for static mapped area
>   ARM: mm: use static_vm for managing static mapped areas
>
>  arch/arm/include/asm/mach/static_vm.h |   51 ++++++++
>  arch/arm/mm/Makefile                  |    2 +-
>  arch/arm/mm/ioremap.c                 |   69 ++++-------
>  arch/arm/mm/mm.h                      |   10 --
>  arch/arm/mm/mmu.c                     |   55 +++++----
>  arch/arm/mm/static_vm.c               |   97 ++++++++++++++++
>  arch/arm/mm/vmregion.c                |  205 ---------------------------------
>  arch/arm/mm/vmregion.h                |   31 -----
>  8 files changed, 208 insertions(+), 312 deletions(-)
>  create mode 100644 arch/arm/include/asm/mach/static_vm.h
>  create mode 100644 arch/arm/mm/static_vm.c
>  delete mode 100644 arch/arm/mm/vmregion.c
>  delete mode 100644 arch/arm/mm/vmregion.h
>
> --
> 1.7.9.5
>

Hello, Russell.

Could you review this patchset, please?
I send another patchset to mm community on top of this.
That one is related to this patchset,
so I want to get a review about this patchset :)

Thanks.

Re: [PATCH v2 0/3] introduce static_vm for ARM-specific static mapped area

[JoonSoo Kim]

2012/12/7 JoonSoo Kim <js1304@gmail.com>:
> 2012/11/28 Joonsoo Kim <js1304@gmail.com>:
>> In current implementation, we used ARM-specific flag, that is,
>> VM_ARM_STATIC_MAPPING, for distinguishing ARM specific static mapped area.
>> The purpose of static mapped area is to re-use static mapped area when
>> entire physical address range of the ioremap request can be covered
>> by this area.
>>
>> This implementation causes needless overhead for some cases.
>> For example, assume that there is only one static mapped area and
>> vmlist has 300 areas. Every time we call ioremap, we check 300 areas for
>> deciding whether it is matched or not. Moreover, even if there is
>> no static mapped area and vmlist has 300 areas, every time we call
>> ioremap, we check 300 areas in now.
>>
>> If we construct a extra list for static mapped area, we can eliminate
>> above mentioned overhead.
>> With a extra list, if there is one static mapped area,
>> we just check only one area and proceed next operation quickly.
>>
>> In fact, it is not a critical problem, because ioremap is not frequently
>> used. But reducing overhead is better idea.
>>
>> Another reason for doing this work is for removing architecture dependency
>> on vmalloc layer. I think that vmlist and vmlist_lock is internal data
>> structure for vmalloc layer. Some codes for debugging and stat inevitably
>> use vmlist and vmlist_lock. But it is preferable that they are used
>> as least as possible in outside of vmalloc.c
>>
>> Changelog
>> v1->v2:
>>   [2/3]: patch description is improved.
>>   Rebased on v3.7-rc7
>>
>> Joonsoo Kim (3):
>>   ARM: vmregion: remove vmregion code entirely
>>   ARM: static_vm: introduce an infrastructure for static mapped area
>>   ARM: mm: use static_vm for managing static mapped areas
>>
>>  arch/arm/include/asm/mach/static_vm.h |   51 ++++++++
>>  arch/arm/mm/Makefile                  |    2 +-
>>  arch/arm/mm/ioremap.c                 |   69 ++++-------
>>  arch/arm/mm/mm.h                      |   10 --
>>  arch/arm/mm/mmu.c                     |   55 +++++----
>>  arch/arm/mm/static_vm.c               |   97 ++++++++++++++++
>>  arch/arm/mm/vmregion.c                |  205 ---------------------------------
>>  arch/arm/mm/vmregion.h                |   31 -----
>>  8 files changed, 208 insertions(+), 312 deletions(-)
>>  create mode 100644 arch/arm/include/asm/mach/static_vm.h
>>  create mode 100644 arch/arm/mm/static_vm.c
>>  delete mode 100644 arch/arm/mm/vmregion.c
>>  delete mode 100644 arch/arm/mm/vmregion.h
>>
>> --
>> 1.7.9.5
>>
>
> Hello, Russell.
>
> Could you review this patchset, please?
> I send another patchset to mm community on top of this.
> That one is related to this patchset,
> so I want to get a review about this patchset :)
>
> Thanks.

Hello.

Is there anyone to review this patchset?
Please let me know what I should do in order to take a review :)

Thanks.