[rfc][patch] mm: vmap rewrite #2
From: Nick Piggin
Date: Thu Jun 12 2008 - 16:19:06 EST
Made much more progress on this, it's now pretty stable and ready for
wider testing.
Changes since last time:
- builds and runs nicely on mainline kernel
- all kernel and user APIs are restored
- flush TLB without the vmap lock held
- scan for lazy freed mappings without vmap lock held
- attempt to scale per-CPU size in case of a tiny (32-bit) VMALLOC area
and lots of CPUs
- only TLB flush on vm_unmap_aliases if there actually were any lazy mappings
- lots of little bugs fixed
- basically it is ready for wider testing
Rewrite the vmap allocator to use rbtrees and lazy tlb flushing, and provide a
fast, scalable percpu frontend for small vmaps.
XEN and PAT and such do not like deferred TLB flushing because they can't
always handle multiple aliasing virtual addresses to a physical address. They
now call vm_unmap_aliases() in order to flush any deferred mappings. That call
is very expensive (well, actually not a lot more expensive than a single vunmap
under the old scheme), however it should be OK if not called too often.
The existing vmalloc API is implemented on top of the rewrite.
To use the high performance interface, you need to change your code to use
vm_map_ram / vm_unmap_ram rather than vmap/vunmap. vmap/vunmap will still
get pretty good speedups from lazy TLB flushing, but don't use the per CPU
frontend.
Very large allocations (ie. larger than 128K for 32-bit 4K page machines,
or 256K for 64-bit 4K) are not going to be so scalable, although again they
will still avoid thrashing the TLBs via lazy unmapping... if there are any
users, we could bump these sizes up a little bit just fine, or I can actually
implement a completely scalable large address size allocator, quite easily but
it will bloat up the virtual address space and make the page tables sparse,
which I want to avoid if possible (ie. it will just be a wait and see thing).
This work is a basic requirement for my large block support in fsblock,
although I will also be using other techniques such as page-at-a-time
algorithms and atomic mappings to further reduce the reliance on vmap.
Basically, when those techniques are used, I anticipate vmap to basically
be almost unused anyway, however this is going to help transition...
As a quick test of performance, I ran a test that loops in the kernel,
linearly mapping then unmapping 4 pages. Different numbers of tests were
run in parallel on an 4 core, 2 socket opteron. Results are in nanoseconds
per map+unmap.
threads vanilla vmap rewrite
1 14700 2900
2 33600 3000
4 49500 2800
8 70631 2900
So with a miserly 8 cores, the rewritten version is already 25x faster. Cost of
the old scheme is probably going up quadratically with the size of the system,
because each TLB flush has to go to N CPUs, and there are N CPUs trying to
do TLB flushing.
In a slightly more realistic test (although with an older and less scalable
version of the patch), I ripped the not-very-good vunmap batching code out of
XFS, and implemented the large buffer mapping with vm_map_ram and
vm_unmap_ram... along with a couple of other tricks, I was able to speed up a
large directory workload by 20x on a 64 CPU system. Basically I believe
vmap/vunmap is actually sped up a lot more than 20x on such a system, but I'm
running into other locks now. vmap is pretty well blown off the profiles.
Before:
1352059 total 0.1401
798784 _write_lock 8320.6667 <- vmlist_lock
529313 default_idle 1181.5022
15242 smp_call_function 15.8771 <- vmap tlb flushing
2472 __get_vm_area_node 1.9312 <- vmap
1762 remove_vm_area 4.5885 <- vunmap
316 map_vm_area 0.2297 <- vmap
312 kfree 0.1950
300 _spin_lock 3.1250
252 sn_send_IPI_phys 0.4375 <- tlb flushing
238 vmap 0.8264 <- vmap
216 find_lock_page 0.5192
196 find_next_bit 0.3603
136 sn2_send_IPI 0.2024
130 pio_phys_write_mmr 2.0312
118 unmap_kernel_range 0.1229
After:
78406 total 0.0081
40053 default_idle 89.4040
33576 ia64_spinlock_contention 349.7500
1650 _spin_lock 17.1875
319 __reg_op 0.5538
281 _atomic_dec_and_lock 1.0977
153 mutex_unlock 1.5938
123 iget_locked 0.1671
117 xfs_dir_lookup 0.1662
117 dput 0.1406
114 xfs_iget_core 0.0268
92 xfs_da_hashname 0.1917
75 d_alloc 0.0670
68 vmap_page_range 0.0462 <- vmap
58 kmem_cache_alloc 0.0604
57 memset 0.0540
52 rb_next 0.1625
50 __copy_user 0.0208
49 bitmap_find_free_region 0.2188 <- vmap
46 ia64_sn_udelay 0.1106
45 find_inode_fast 0.1406
42 memcmp 0.2188
42 finish_task_switch 0.1094
42 __d_lookup 0.0410
40 radix_tree_lookup_slot 0.1250
37 _spin_unlock_irqrestore 0.3854
36 xfs_bmapi 0.0050
36 kmem_cache_free 0.0256
35 xfs_vn_getattr 0.0322
34 radix_tree_lookup 0.1062
33 __link_path_walk 0.0035
31 xfs_da_do_buf 0.0091
30 _xfs_buf_find 0.0204
28 find_get_page 0.0875
27 xfs_iread 0.0241
27 __strncpy_from_user 0.2812
26 _xfs_buf_initialize 0.0406
24 _xfs_buf_lookup_pages 0.0179
24 vunmap_page_range 0.0250 <- vunmap
23 find_lock_page 0.0799
22 vm_map_ram 0.0087 <- vmap
20 kfree 0.0125
19 put_page 0.0330
18 __kmalloc 0.0176
17 xfs_da_node_lookup_int 0.0086
17 _read_lock 0.0885
17 page_waitqueue 0.0664
vmap has gone from being the top 5 on the profiles and flushing the
shit out of all TLBs, to using less than 1% of kernel time.
Index: linux-2.6/fs/xfs/linux-2.6/xfs_buf.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_buf.c
+++ linux-2.6/fs/xfs/linux-2.6/xfs_buf.c
@@ -166,75 +166,6 @@ test_page_region(
}
/*
- * Mapping of multi-page buffers into contiguous virtual space
- */
-
-typedef struct a_list {
- void *vm_addr;
- struct a_list *next;
-} a_list_t;
-
-static a_list_t *as_free_head;
-static int as_list_len;
-static DEFINE_SPINLOCK(as_lock);
-
-/*
- * Try to batch vunmaps because they are costly.
- */
-STATIC void
-free_address(
- void *addr)
-{
- a_list_t *aentry;
-
-#ifdef CONFIG_XEN
- /*
- * Xen needs to be able to make sure it can get an exclusive
- * RO mapping of pages it wants to turn into a pagetable. If
- * a newly allocated page is also still being vmap()ed by xfs,
- * it will cause pagetable construction to fail. This is a
- * quick workaround to always eagerly unmap pages so that Xen
- * is happy.
- */
- vunmap(addr);
- return;
-#endif
-
- aentry = kmalloc(sizeof(a_list_t), GFP_NOWAIT);
- if (likely(aentry)) {
- spin_lock(&as_lock);
- aentry->next = as_free_head;
- aentry->vm_addr = addr;
- as_free_head = aentry;
- as_list_len++;
- spin_unlock(&as_lock);
- } else {
- vunmap(addr);
- }
-}
-
-STATIC void
-purge_addresses(void)
-{
- a_list_t *aentry, *old;
-
- if (as_free_head == NULL)
- return;
-
- spin_lock(&as_lock);
- aentry = as_free_head;
- as_free_head = NULL;
- as_list_len = 0;
- spin_unlock(&as_lock);
-
- while ((old = aentry) != NULL) {
- vunmap(aentry->vm_addr);
- aentry = aentry->next;
- kfree(old);
- }
-}
-
-/*
* Internal xfs_buf_t object manipulation
*/
@@ -334,7 +265,7 @@ xfs_buf_free(
uint i;
if ((bp->b_flags & XBF_MAPPED) && (bp->b_page_count > 1))
- free_address(bp->b_addr - bp->b_offset);
+ vm_unmap_ram(bp->b_addr - bp->b_offset, bp->b_page_count);
for (i = 0; i < bp->b_page_count; i++) {
struct page *page = bp->b_pages[i];
@@ -456,10 +387,8 @@ _xfs_buf_map_pages(
bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
bp->b_flags |= XBF_MAPPED;
} else if (flags & XBF_MAPPED) {
- if (as_list_len > 64)
- purge_addresses();
- bp->b_addr = vmap(bp->b_pages, bp->b_page_count,
- VM_MAP, PAGE_KERNEL);
+ bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
+ -1, PAGE_KERNEL);
if (unlikely(bp->b_addr == NULL))
return -ENOMEM;
bp->b_addr += bp->b_offset;
@@ -1739,8 +1668,6 @@ xfsbufd(
count++;
}
- if (as_list_len > 0)
- purge_addresses();
if (count)
blk_run_address_space(target->bt_mapping);
Index: linux-2.6/mm/vmalloc.c
===================================================================
--- linux-2.6.orig/mm/vmalloc.c
+++ linux-2.6/mm/vmalloc.c
@@ -8,6 +8,7 @@
* Numa awareness, Christoph Lameter, SGI, June 2005
*/
+#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/highmem.h>
@@ -18,16 +19,17 @@
#include <linux/debugobjects.h>
#include <linux/vmalloc.h>
#include <linux/kallsyms.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/radix-tree.h>
+#include <linux/rcupdate.h>
+#include <asm/atomic.h>
#include <asm/uaccess.h>
#include <asm/tlbflush.h>
-DEFINE_RWLOCK(vmlist_lock);
-struct vm_struct *vmlist;
-
-static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
- int node, void *caller);
+/*** Page table manipulation functions ***/
static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
{
@@ -40,8 +42,7 @@ static void vunmap_pte_range(pmd_t *pmd,
} while (pte++, addr += PAGE_SIZE, addr != end);
}
-static inline void vunmap_pmd_range(pud_t *pud, unsigned long addr,
- unsigned long end)
+static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
{
pmd_t *pmd;
unsigned long next;
@@ -55,8 +56,7 @@ static inline void vunmap_pmd_range(pud_
} while (pmd++, addr = next, addr != end);
}
-static inline void vunmap_pud_range(pgd_t *pgd, unsigned long addr,
- unsigned long end)
+static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
{
pud_t *pud;
unsigned long next;
@@ -70,12 +70,10 @@ static inline void vunmap_pud_range(pgd_
} while (pud++, addr = next, addr != end);
}
-void unmap_kernel_range(unsigned long addr, unsigned long size)
+static void vunmap_page_range(unsigned long addr, unsigned long end)
{
pgd_t *pgd;
unsigned long next;
- unsigned long start = addr;
- unsigned long end = addr + size;
BUG_ON(addr >= end);
pgd = pgd_offset_k(addr);
@@ -86,16 +84,10 @@ void unmap_kernel_range(unsigned long ad
continue;
vunmap_pud_range(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
- flush_tlb_kernel_range(start, end);
-}
-
-static void unmap_vm_area(struct vm_struct *area)
-{
- unmap_kernel_range((unsigned long)area->addr, area->size);
}
static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
- unsigned long end, pgprot_t prot, struct page ***pages)
+ unsigned long end, pgprot_t prot, struct page **pages, int *nr)
{
pte_t *pte;
@@ -103,18 +95,24 @@ static int vmap_pte_range(pmd_t *pmd, un
if (!pte)
return -ENOMEM;
do {
- struct page *page = **pages;
- WARN_ON(!pte_none(*pte));
- if (!page)
+ struct page *page = pages[*nr];
+
+ if (unlikely(!pte_none(*pte))) {
+ WARN_ON(1);
+ return -EBUSY;
+ }
+ if (unlikely(!page)) {
+ WARN_ON(1);
return -ENOMEM;
+ }
set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
- (*pages)++;
+ (*nr)++;
} while (pte++, addr += PAGE_SIZE, addr != end);
return 0;
}
-static inline int vmap_pmd_range(pud_t *pud, unsigned long addr,
- unsigned long end, pgprot_t prot, struct page ***pages)
+static int vmap_pmd_range(pud_t *pud, unsigned long addr,
+ unsigned long end, pgprot_t prot, struct page **pages, int *nr)
{
pmd_t *pmd;
unsigned long next;
@@ -124,14 +122,14 @@ static inline int vmap_pmd_range(pud_t *
return -ENOMEM;
do {
next = pmd_addr_end(addr, end);
- if (vmap_pte_range(pmd, addr, next, prot, pages))
+ if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
return -ENOMEM;
} while (pmd++, addr = next, addr != end);
return 0;
}
-static inline int vmap_pud_range(pgd_t *pgd, unsigned long addr,
- unsigned long end, pgprot_t prot, struct page ***pages)
+static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
+ unsigned long end, pgprot_t prot, struct page **pages, int *nr)
{
pud_t *pud;
unsigned long next;
@@ -141,50 +139,48 @@ static inline int vmap_pud_range(pgd_t *
return -ENOMEM;
do {
next = pud_addr_end(addr, end);
- if (vmap_pmd_range(pud, addr, next, prot, pages))
+ if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
return -ENOMEM;
} while (pud++, addr = next, addr != end);
return 0;
}
-int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
+static int vmap_page_range(unsigned long addr, unsigned long end,
+ pgprot_t prot, struct page **pages)
{
pgd_t *pgd;
unsigned long next;
- unsigned long addr = (unsigned long) area->addr;
- unsigned long end = addr + area->size - PAGE_SIZE;
- int err;
+ int err = 0;
+ int nr = 0;
BUG_ON(addr >= end);
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
- err = vmap_pud_range(pgd, addr, next, prot, pages);
+ err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
if (err)
break;
} while (pgd++, addr = next, addr != end);
- flush_cache_vmap((unsigned long) area->addr, end);
- return err;
+ flush_cache_vmap(addr, end);
+ return err ? : nr;
}
-EXPORT_SYMBOL_GPL(map_vm_area);
/*
- * Map a vmalloc()-space virtual address to the physical page.
+ * Walk a vmap address to the struct page it maps.
*/
struct page *vmalloc_to_page(const void *vmalloc_addr)
{
unsigned long addr = (unsigned long) vmalloc_addr;
struct page *page = NULL;
pgd_t *pgd = pgd_offset_k(addr);
- pud_t *pud;
- pmd_t *pmd;
- pte_t *ptep, pte;
if (!pgd_none(*pgd)) {
- pud = pud_offset(pgd, addr);
+ pud_t *pud = pud_offset(pgd, addr);
if (!pud_none(*pud)) {
- pmd = pmd_offset(pud, addr);
+ pmd_t *pmd = pmd_offset(pud, addr);
if (!pmd_none(*pmd)) {
+ pte_t *ptep, pte;
+
ptep = pte_offset_map(pmd, addr);
pte = *ptep;
if (pte_present(pte))
@@ -206,13 +202,628 @@ unsigned long vmalloc_to_pfn(const void
}
EXPORT_SYMBOL(vmalloc_to_pfn);
-static struct vm_struct *
-__get_vm_area_node(unsigned long size, unsigned long flags, unsigned long start,
- unsigned long end, int node, gfp_t gfp_mask, void *caller)
+
+/*** Global kva allocator ***/
+
+#define VM_LAZY_FREE 0x01
+#define VM_LAZY_FREEING 0x02
+#define VM_VM_AREA 0x04
+
+struct vmap_area {
+ unsigned long va_start;
+ unsigned long va_end;
+ unsigned long flags;
+ struct rb_node rb_node;
+ struct list_head list;
+ struct list_head purge_list;
+ void *private;
+ struct rcu_head rcu_head;
+};
+
+static DEFINE_SPINLOCK(vmap_area_lock);
+static struct rb_root vmap_area_root = RB_ROOT;
+static LIST_HEAD(vmap_area_list);
+
+static struct vmap_area *__find_vmap_area(unsigned long addr)
+{
+ struct rb_node *n = vmap_area_root.rb_node;
+
+ while (n) {
+ struct vmap_area *va;
+
+ va = rb_entry(n, struct vmap_area, rb_node);
+ if (addr < va->va_start)
+ n = n->rb_left;
+ else if (addr > va->va_start)
+ n = n->rb_right;
+ else
+ return va;
+ }
+
+ return NULL;
+}
+
+static void __insert_vmap_area(struct vmap_area *va)
{
- struct vm_struct **p, *tmp, *area;
- unsigned long align = 1;
+ struct rb_node **p = &vmap_area_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct rb_node *tmp;
+
+ while (*p) {
+ struct vmap_area *tmp;
+
+ parent = *p;
+ tmp = rb_entry(parent, struct vmap_area, rb_node);
+ if (va->va_start < tmp->va_end)
+ p = &(*p)->rb_left;
+ else if (va->va_end > tmp->va_start)
+ p = &(*p)->rb_right;
+ else
+ BUG();
+ }
+
+ rb_link_node(&va->rb_node, parent, p);
+ rb_insert_color(&va->rb_node, &vmap_area_root);
+
+ /* address-sort this list so it is usable like the vmlist */
+ tmp = rb_prev(&va->rb_node);
+ if (tmp) {
+ struct vmap_area *prev;
+ prev = rb_entry(tmp, struct vmap_area, rb_node);
+ list_add_rcu(&va->list, &prev->list);
+ } else
+ list_add_rcu(&va->list, &vmap_area_list);
+}
+
+static void purge_vmap_area_lazy(void);
+
+static struct vmap_area *alloc_vmap_area(unsigned long size, unsigned long align,
+ unsigned long vstart, unsigned long vend,
+ int node, gfp_t gfp_mask)
+{
+ struct vmap_area *va;
+ struct rb_node *n;
unsigned long addr;
+ int purged = 0;
+
+ BUG_ON(size & ~PAGE_MASK);
+
+ addr = ALIGN(vstart, align);
+
+ va = kmalloc_node(sizeof(struct vmap_area),
+ gfp_mask & GFP_RECLAIM_MASK, node);
+ if (unlikely(!va))
+ return ERR_PTR(-ENOMEM);
+
+retry:
+ spin_lock(&vmap_area_lock);
+ /* XXX: could have a last_hole cache */
+ n = vmap_area_root.rb_node;
+ if (n) {
+ struct vmap_area *first = NULL;
+
+ do {
+ struct vmap_area *tmp;
+ tmp = rb_entry(n, struct vmap_area, rb_node);
+ if (tmp->va_end >= addr) {
+ if (!first && tmp->va_start <= addr)
+ first = tmp;
+ n = n->rb_left;
+ } else {
+ first = tmp;
+ n = n->rb_right;
+ }
+ } while (n);
+
+ if (!first)
+ goto found;
+
+ if (first->va_end < addr) {
+ n = rb_next(&first->rb_node);
+ if (n)
+ first = rb_entry(n, struct vmap_area, rb_node);
+ else
+ goto found;
+ }
+
+ while (addr + size >= first->va_start && addr + size <= vend) {
+ addr = ALIGN(first->va_end + PAGE_SIZE, align);
+
+ n = rb_next(&first->rb_node);
+ if (n)
+ first = rb_entry(n, struct vmap_area, rb_node);
+ else
+ goto found;
+ }
+ }
+found:
+ if (addr + size > vend) {
+ spin_unlock(&vmap_area_lock);
+ if (!purged) {
+ purge_vmap_area_lazy();
+ purged = 1;
+ goto retry;
+ }
+ if (printk_ratelimit())
+ printk(KERN_WARNING "vmap allocation failed: "
+ "use vmalloc=<size> to increase size.\n");
+ return ERR_PTR(-EBUSY);
+ }
+
+ BUG_ON(addr & (align-1));
+
+ va->va_start = addr;
+ va->va_end = addr + size;
+ va->flags = 0;
+ __insert_vmap_area(va);
+ spin_unlock(&vmap_area_lock);
+
+ return va;
+}
+
+static void rcu_free_va(struct rcu_head *head)
+{
+ struct vmap_area *va = container_of(head, struct vmap_area, rcu_head);
+
+ kfree(va);
+}
+
+static void __free_vmap_area(struct vmap_area *va)
+{
+ BUG_ON(RB_EMPTY_NODE(&va->rb_node));
+ rb_erase(&va->rb_node, &vmap_area_root);
+ RB_CLEAR_NODE(&va->rb_node);
+ list_del_rcu(&va->list);
+
+ call_rcu(&va->rcu_head, rcu_free_va);
+}
+
+static void free_vmap_area(struct vmap_area *va)
+{
+ spin_lock(&vmap_area_lock);
+ __free_vmap_area(va);
+ spin_unlock(&vmap_area_lock);
+}
+
+static void unmap_vmap_area(struct vmap_area *va)
+{
+ vunmap_page_range(va->va_start, va->va_end);
+}
+
+#define LAZY_MAX (64*1024*1024 / PAGE_SIZE)
+static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
+
+static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
+ int sync, int force_flush)
+{
+ static DEFINE_SPINLOCK(purge_lock);
+ LIST_HEAD(valist);
+ struct vmap_area *va;
+ int nr = 0;
+
+ if (!sync && !force_flush) {
+ if (!spin_trylock(&purge_lock))
+ return;
+ } else
+ spin_lock(&purge_lock);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(va, &vmap_area_list, list) {
+ if (va->flags & VM_LAZY_FREE) {
+ if (va->va_start < *start)
+ *start = va->va_start;
+ if (va->va_end > *end)
+ *end = va->va_end;
+ nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
+ unmap_vmap_area(va);
+ list_add_tail(&va->purge_list, &valist);
+ va->flags |= VM_LAZY_FREEING;
+ va->flags &= ~VM_LAZY_FREE;
+ }
+ }
+ rcu_read_unlock();
+
+ if (nr) {
+ BUG_ON(nr > atomic_read(&vmap_lazy_nr));
+ atomic_sub(nr, &vmap_lazy_nr);
+ }
+
+ if (nr || force_flush)
+ flush_tlb_kernel_range(*start, *end);
+
+ if (nr) {
+ spin_lock(&vmap_area_lock);
+ list_for_each_entry(va, &valist, purge_list)
+ __free_vmap_area(va);
+ spin_unlock(&vmap_area_lock);
+ }
+ spin_unlock(&purge_lock);
+}
+
+static void purge_vmap_area_lazy(void)
+{
+ unsigned long start = ULONG_MAX, end = 0;
+
+ __purge_vmap_area_lazy(&start, &end, 0, 0);
+}
+
+static void free_unmap_vmap_area(struct vmap_area *va)
+{
+ va->flags |= VM_LAZY_FREE;
+ atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr);
+ if (unlikely(atomic_read(&vmap_lazy_nr) > LAZY_MAX))
+ purge_vmap_area_lazy();
+}
+
+static struct vmap_area *find_vmap_area(unsigned long addr)
+{
+ struct vmap_area *va;
+
+ spin_lock(&vmap_area_lock);
+ va = __find_vmap_area(addr);
+ spin_unlock(&vmap_area_lock);
+
+ return va;
+}
+
+static void free_unmap_vmap_area_addr(unsigned long addr)
+{
+ struct vmap_area *va;
+
+ va = find_vmap_area(addr);
+ BUG_ON(!va);
+ free_unmap_vmap_area(va);
+}
+
+
+/*** Per cpu kva allocator ***/
+
+/*
+ * vmap space is limited especially on 32 bit architectures. Ensure there is
+ * room for at least 16 percpu vmap blocks per CPU.
+ */
+#define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START)
+#define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE)
+#define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */
+#define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */
+#define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
+#define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
+#define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
+#define VMAP_BBMAP_BITS VMAP_MIN(VMAP_BBMAP_BITS_MAX, VMAP_MAX(VMAP_BBMAP_BITS_MIN, VMALLOC_PAGES / NR_CPUS / 16))
+
+#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
+
+struct vmap_block_queue {
+ spinlock_t lock;
+ struct list_head free;
+ struct list_head dirty;
+ unsigned int nr_dirty;
+};
+
+struct vmap_block {
+ spinlock_t lock;
+ struct vmap_area *va;
+ struct vmap_block_queue *vbq;
+ unsigned long free, dirty;
+ DECLARE_BITMAP(alloc_map, VMAP_BBMAP_BITS);
+ DECLARE_BITMAP(dirty_map, VMAP_BBMAP_BITS);
+ union {
+ struct {
+ struct list_head free_list;
+ struct list_head dirty_list;
+ };
+ struct rcu_head rcu_head;
+ };
+};
+
+static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
+
+static DEFINE_SPINLOCK(vmap_block_tree_lock);
+static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
+/* XXX: have global list of vmap blocks to fall back on? */
+
+static unsigned long addr_to_vb_idx(unsigned long addr)
+{
+ addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
+ addr /= VMAP_BLOCK_SIZE;
+ return addr;
+}
+
+static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
+{
+ struct vmap_block_queue *vbq;
+ struct vmap_block *vb;
+ struct vmap_area *va;
+ int node, err;
+
+ node = numa_node_id();
+
+ vb = kmalloc_node(sizeof(struct vmap_block),
+ gfp_mask & GFP_RECLAIM_MASK, node);
+ if (unlikely(!vb))
+ return ERR_PTR(-ENOMEM);
+
+ va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
+ VMALLOC_START, VMALLOC_END,
+ node, gfp_mask);
+ if (unlikely(IS_ERR(va))) {
+ kfree(vb);
+ return ERR_PTR(PTR_ERR(va));
+ }
+
+ err = radix_tree_preload(gfp_mask);
+ if (unlikely(err)) {
+ kfree(vb);
+ free_vmap_area(va);
+ return ERR_PTR(err);
+ }
+
+ spin_lock_init(&vb->lock);
+ vb->va = va;
+ vb->free = VMAP_BBMAP_BITS;
+ vb->dirty = 0;
+ bitmap_zero(vb->alloc_map, VMAP_BBMAP_BITS);
+ bitmap_zero(vb->dirty_map, VMAP_BBMAP_BITS);
+ INIT_LIST_HEAD(&vb->free_list);
+ INIT_LIST_HEAD(&vb->dirty_list);
+
+ spin_lock(&vmap_block_tree_lock);
+ err = radix_tree_insert(&vmap_block_tree, addr_to_vb_idx(va->va_start), vb);
+ spin_unlock(&vmap_block_tree_lock);
+ BUG_ON(err);
+ radix_tree_preload_end();
+
+ vbq = &get_cpu_var(vmap_block_queue);
+ vb->vbq = vbq;
+ spin_lock(&vbq->lock);
+ list_add(&vb->free_list, &vbq->free);
+ spin_unlock(&vbq->lock);
+ put_cpu_var(vmap_cpu_blocks);
+
+ return vb;
+}
+
+static void rcu_free_vb(struct rcu_head *head)
+{
+ struct vmap_block *vb = container_of(head, struct vmap_block, rcu_head);
+
+ kfree(vb);
+}
+
+static void free_vmap_block(struct vmap_block *vb)
+{
+ struct vmap_block *tmp;
+
+ spin_lock(&vb->vbq->lock);
+ if (!list_empty(&vb->free_list))
+ list_del(&vb->free_list);
+ if (!list_empty(&vb->dirty_list))
+ list_del(&vb->dirty_list);
+ spin_unlock(&vb->vbq->lock);
+
+ spin_lock(&vmap_block_tree_lock);
+ tmp = radix_tree_delete(&vmap_block_tree, addr_to_vb_idx(vb->va->va_start));
+ spin_unlock(&vmap_block_tree_lock);
+ BUG_ON(tmp != vb);
+
+ free_unmap_vmap_area(vb->va);
+ call_rcu(&vb->rcu_head, rcu_free_vb);
+}
+
+static void *vb_alloc(unsigned long size,
+ gfp_t gfp_mask)
+{
+ struct vmap_block_queue *vbq;
+ struct vmap_block *vb;
+ unsigned long addr = 0;
+ unsigned int order;
+
+ BUG_ON(size & ~PAGE_MASK);
+ BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
+ order = get_order(size);
+
+again:
+ rcu_read_lock();
+ vbq = &get_cpu_var(vmap_block_queue);
+ list_for_each_entry_rcu(vb, &vbq->free, free_list) {
+ int i;
+
+ spin_lock(&vb->lock);
+ i = bitmap_find_free_region(vb->alloc_map, VMAP_BBMAP_BITS, order);
+
+ if (i >= 0) {
+ addr = vb->va->va_start + (i << PAGE_SHIFT);
+ BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(vb->va->va_start));
+ vb->free -= 1UL << order;
+ if (vb->free == 0) {
+ spin_lock(&vbq->lock);
+ list_del_init(&vb->free_list);
+ spin_unlock(&vbq->lock);
+ }
+ spin_unlock(&vb->lock);
+ break;
+ }
+ spin_unlock(&vb->lock);
+ }
+ put_cpu_var(vmap_cpu_blocks);
+ rcu_read_unlock();
+
+ if (!addr) {
+ vb = new_vmap_block(gfp_mask);
+ if (IS_ERR(vb))
+ return vb;
+ goto again;
+ }
+
+ return (void *)addr;
+}
+
+static void vb_free(const void *addr, unsigned long size)
+{
+ unsigned long offset;
+ unsigned int order;
+ struct vmap_block *vb;
+
+ BUG_ON(size & ~PAGE_MASK);
+ BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
+ order = get_order(size);
+
+ offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
+
+ rcu_read_lock();
+ vb = radix_tree_lookup(&vmap_block_tree, addr_to_vb_idx((unsigned long)addr));
+ rcu_read_unlock();
+ BUG_ON(!vb);
+
+ spin_lock(&vb->lock);
+ bitmap_allocate_region(vb->dirty_map, offset >> PAGE_SHIFT, order);
+ if (!vb->dirty) {
+ spin_lock(&vb->vbq->lock);
+ list_add(&vb->dirty_list, &vb->vbq->dirty);
+ spin_unlock(&vb->vbq->lock);
+ }
+ vb->dirty += 1UL << order;
+ if (vb->dirty == VMAP_BBMAP_BITS) {
+ BUG_ON(vb->free || !list_empty(&vb->free_list));
+ spin_unlock(&vb->lock);
+ free_vmap_block(vb);
+ } else
+ spin_unlock(&vb->lock);
+}
+
+void vm_unmap_aliases(void)
+{
+ unsigned long start = ULONG_MAX, end = 0;
+ int cpu;
+ int flush = 0;
+
+ for_each_possible_cpu(cpu) {
+ struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
+ struct vmap_block *vb;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(vb, &vbq->free, free_list) {
+ int i;
+
+ spin_lock(&vb->lock);
+ for (i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
+ i < VMAP_BBMAP_BITS;
+ i = find_next_bit(vb->dirty_map, VMAP_BBMAP_BITS, i)){
+ unsigned long s, e;
+ int j;
+ j = find_next_zero_bit(vb->dirty_map,
+ VMAP_BBMAP_BITS, i);
+
+ s = vb->va->va_start + (i << PAGE_SHIFT);
+ e = vb->va->va_start + (j << PAGE_SHIFT);
+ vunmap_page_range(s, e);
+ flush = 1;
+
+ if (s < start)
+ start = s;
+ if (e > end)
+ end = e;
+
+ i = j;
+ }
+ spin_unlock(&vb->lock);
+ }
+ rcu_read_unlock();
+ }
+
+ __purge_vmap_area_lazy(&start, &end, 1, flush);
+}
+
+void vm_unmap_ram(const void *mem, unsigned int count)
+{
+ unsigned long size = count << PAGE_SHIFT;
+ unsigned long addr = (unsigned long)mem;
+
+ BUG_ON(!addr || addr < VMALLOC_START || addr > VMALLOC_END || (addr & (PAGE_SIZE-1)));
+
+ debug_check_no_locks_freed(mem, size);
+
+ if (likely(count <= VMAP_MAX_ALLOC))
+ vb_free(mem, size);
+ else
+ free_unmap_vmap_area_addr(addr);
+}
+
+void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
+{
+ unsigned long size = count << PAGE_SHIFT;
+ unsigned long addr;
+ void *mem;
+
+ if (likely(count <= VMAP_MAX_ALLOC)) {
+ mem = vb_alloc(size, GFP_KERNEL);
+ if (IS_ERR(mem))
+ return NULL;
+ addr = (unsigned long)mem;
+ } else {
+ struct vmap_area *va;
+ va = alloc_vmap_area(size, PAGE_SIZE, VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
+ if (IS_ERR(va))
+ return NULL;
+
+ addr = va->va_start;
+ mem = (void *)addr;
+ }
+ if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
+ vm_unmap_ram(mem, count);
+ return NULL;
+ }
+ return mem;
+}
+
+void __init vmalloc_init(void)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct vmap_block_queue *vbq;
+
+ vbq = &per_cpu(vmap_block_queue, i);
+ spin_lock_init(&vbq->lock);
+ INIT_LIST_HEAD(&vbq->free);
+ INIT_LIST_HEAD(&vbq->dirty);
+ vbq->nr_dirty = 0;
+ }
+}
+
+void unmap_kernel_range(unsigned long addr, unsigned long size)
+{
+ unsigned long end = addr + size;
+ vunmap_page_range(addr, end);
+ flush_tlb_kernel_range(addr, end);
+}
+
+int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
+{
+ unsigned long addr = (unsigned long)area->addr;
+ int err;
+ err = vmap_page_range(addr, addr + area->size- PAGE_SIZE, prot, *pages);
+ if (err > 0) {
+ *pages += err;
+ err = 0;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(map_vm_area);
+
+/*** Old vmalloc interfaces ***/
+DEFINE_RWLOCK(vmlist_lock);
+struct vm_struct *vmlist;
+
+static struct vm_struct *__get_vm_area_node(unsigned long size,
+ unsigned long flags, unsigned long start, unsigned long end,
+ int node, gfp_t gfp_mask, void *caller)
+{
+ static struct vmap_area *va;
+ struct vm_struct *area;
+ struct vm_struct *tmp, **p;
+ unsigned long align = 1;
BUG_ON(in_interrupt());
if (flags & VM_IOREMAP) {
@@ -225,13 +836,12 @@ __get_vm_area_node(unsigned long size, u
align = 1ul << bit;
}
- addr = ALIGN(start, align);
+
size = PAGE_ALIGN(size);
if (unlikely(!size))
return NULL;
area = kmalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
-
if (unlikely(!area))
return NULL;
@@ -240,48 +850,32 @@ __get_vm_area_node(unsigned long size, u
*/
size += PAGE_SIZE;
- write_lock(&vmlist_lock);
- for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) {
- if ((unsigned long)tmp->addr < addr) {
- if((unsigned long)tmp->addr + tmp->size >= addr)
- addr = ALIGN(tmp->size +
- (unsigned long)tmp->addr, align);
- continue;
- }
- if ((size + addr) < addr)
- goto out;
- if (size + addr <= (unsigned long)tmp->addr)
- goto found;
- addr = ALIGN(tmp->size + (unsigned long)tmp->addr, align);
- if (addr > end - size)
- goto out;
- }
- if ((size + addr) < addr)
- goto out;
- if (addr > end - size)
- goto out;
-
-found:
- area->next = *p;
- *p = area;
+ va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
+ if (IS_ERR(va)) {
+ kfree(area);
+ return NULL;
+ }
area->flags = flags;
- area->addr = (void *)addr;
+ area->addr = (void *)va->va_start;
area->size = size;
area->pages = NULL;
area->nr_pages = 0;
area->phys_addr = 0;
area->caller = caller;
+ va->private = area;
+ va->flags |= VM_VM_AREA;
+
+ write_lock(&vmlist_lock);
+ for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
+ if (tmp->addr >= area->addr)
+ break;
+ }
+ area->next = *p;
+ *p = area;
write_unlock(&vmlist_lock);
return area;
-
-out:
- write_unlock(&vmlist_lock);
- kfree(area);
- if (printk_ratelimit())
- printk(KERN_WARNING "allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.\n");
- return NULL;
}
struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
@@ -321,39 +915,15 @@ struct vm_struct *get_vm_area_node(unsig
gfp_mask, __builtin_return_address(0));
}
-/* Caller must hold vmlist_lock */
-static struct vm_struct *__find_vm_area(const void *addr)
+static struct vm_struct *find_vm_area(const void *addr)
{
- struct vm_struct *tmp;
-
- for (tmp = vmlist; tmp != NULL; tmp = tmp->next) {
- if (tmp->addr == addr)
- break;
- }
+ struct vmap_area *va;
- return tmp;
-}
+ va = find_vmap_area((unsigned long)addr);
+ if (va && va->flags & VM_VM_AREA)
+ return va->private;
-/* Caller must hold vmlist_lock */
-static struct vm_struct *__remove_vm_area(const void *addr)
-{
- struct vm_struct **p, *tmp;
-
- for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) {
- if (tmp->addr == addr)
- goto found;
- }
return NULL;
-
-found:
- unmap_vm_area(tmp);
- *p = tmp->next;
-
- /*
- * Remove the guard page.
- */
- tmp->size -= PAGE_SIZE;
- return tmp;
}
/**
@@ -366,11 +936,24 @@ found:
*/
struct vm_struct *remove_vm_area(const void *addr)
{
- struct vm_struct *v;
- write_lock(&vmlist_lock);
- v = __remove_vm_area(addr);
- write_unlock(&vmlist_lock);
- return v;
+ struct vmap_area *va;
+
+ va = find_vmap_area((unsigned long)addr);
+ if (va && va->flags & VM_VM_AREA) {
+ struct vm_struct *vm = va->private;
+ struct vm_struct *tmp, **p;
+ free_unmap_vmap_area(va);
+ vm->size -= PAGE_SIZE;
+
+ write_lock(&vmlist_lock);
+ for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
+ ;
+ *p = tmp->next;
+ write_unlock(&vmlist_lock);
+
+ return vm;
+ }
+ return NULL;
}
static void __vunmap(const void *addr, int deallocate_pages)
@@ -482,6 +1065,8 @@ void *vmap(struct page **pages, unsigned
}
EXPORT_SYMBOL(vmap);
+static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
+ int node, void *caller);
static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
pgprot_t prot, int node, void *caller)
{
@@ -608,10 +1193,8 @@ void *vmalloc_user(unsigned long size)
ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
if (ret) {
- write_lock(&vmlist_lock);
- area = __find_vm_area(ret);
+ area = find_vm_area(ret);
area->flags |= VM_USERMAP;
- write_unlock(&vmlist_lock);
}
return ret;
}
@@ -691,10 +1274,8 @@ void *vmalloc_32_user(unsigned long size
ret = __vmalloc(size, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL);
if (ret) {
- write_lock(&vmlist_lock);
- area = __find_vm_area(ret);
+ area = find_vm_area(ret);
area->flags |= VM_USERMAP;
- write_unlock(&vmlist_lock);
}
return ret;
}
@@ -795,26 +1376,25 @@ int remap_vmalloc_range(struct vm_area_s
struct vm_struct *area;
unsigned long uaddr = vma->vm_start;
unsigned long usize = vma->vm_end - vma->vm_start;
- int ret;
if ((PAGE_SIZE-1) & (unsigned long)addr)
return -EINVAL;
- read_lock(&vmlist_lock);
- area = __find_vm_area(addr);
+ area = find_vm_area(addr);
if (!area)
- goto out_einval_locked;
+ return -EINVAL;
if (!(area->flags & VM_USERMAP))
- goto out_einval_locked;
+ return -EINVAL;
if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
- goto out_einval_locked;
- read_unlock(&vmlist_lock);
+ return -EINVAL;
addr += pgoff << PAGE_SHIFT;
do {
struct page *page = vmalloc_to_page(addr);
+ int ret;
+
ret = vm_insert_page(vma, uaddr, page);
if (ret)
return ret;
@@ -827,11 +1407,7 @@ int remap_vmalloc_range(struct vm_area_s
/* Prevent "things" like memory migration? VM_flags need a cleanup... */
vma->vm_flags |= VM_RESERVED;
- return ret;
-
-out_einval_locked:
- read_unlock(&vmlist_lock);
- return -EINVAL;
+ return 0;
}
EXPORT_SYMBOL(remap_vmalloc_range);
Index: linux-2.6/include/linux/vmalloc.h
===================================================================
--- linux-2.6.orig/include/linux/vmalloc.h
+++ linux-2.6/include/linux/vmalloc.h
@@ -23,7 +23,6 @@ struct vm_area_struct;
#endif
struct vm_struct {
- /* keep next,addr,size together to speedup lookups */
struct vm_struct *next;
void *addr;
unsigned long size;
@@ -37,6 +36,11 @@ struct vm_struct {
/*
* Highlevel APIs for driver use
*/
+extern void vm_unmap_ram(const void *mem, unsigned int count);
+extern void *vm_map_ram(struct page **pages, unsigned int count,
+ int node, pgprot_t prot);
+extern void vm_unmap_aliases(void);
+
extern void *vmalloc(unsigned long size);
extern void *vmalloc_user(unsigned long size);
extern void *vmalloc_node(unsigned long size, int node);
Index: linux-2.6/init/main.c
===================================================================
--- linux-2.6.orig/init/main.c
+++ linux-2.6/init/main.c
@@ -90,6 +90,7 @@ extern void pidhash_init(void);
extern void pidmap_init(void);
extern void prio_tree_init(void);
extern void radix_tree_init(void);
+extern void vmalloc_init(void);
extern void free_initmem(void);
#ifdef CONFIG_ACPI
extern void acpi_early_init(void);
@@ -635,6 +636,7 @@ asmlinkage void __init start_kernel(void
initrd_start = 0;
}
#endif
+ vmalloc_init();
vfs_caches_init_early();
cpuset_init_early();
mem_init();
Index: linux-2.6/arch/x86/xen/enlighten.c
===================================================================
--- linux-2.6.orig/arch/x86/xen/enlighten.c
+++ linux-2.6/arch/x86/xen/enlighten.c
@@ -708,6 +708,7 @@ static void xen_alloc_ptpage(struct mm_s
/* make sure there are no stray mappings of
this page */
kmap_flush_unused();
+ vm_unmap_aliases();
}
}
Index: linux-2.6/arch/x86/xen/mmu.c
===================================================================
--- linux-2.6.orig/arch/x86/xen/mmu.c
+++ linux-2.6/arch/x86/xen/mmu.c
@@ -438,6 +438,7 @@ void xen_pgd_pin(pgd_t *pgd)
/* re-enable interrupts for kmap_flush_unused */
xen_mc_issue(0);
kmap_flush_unused();
+ vm_unmap_aliases();
xen_mc_batch();
}
Index: linux-2.6/arch/x86/mm/pageattr.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/pageattr.c
+++ linux-2.6/arch/x86/mm/pageattr.c
@@ -722,6 +722,8 @@ static int change_page_attr_set_clr(unsi
WARN_ON_ONCE(1);
}
+ vm_unmap_aliases();
+
cpa.vaddr = addr;
cpa.numpages = numpages;
cpa.mask_set = mask_set;