Re: More convenient way to grab hugepage memory

From: David Gibson
Date: Thu May 13 2004 - 01:24:23 EST

On Thu, May 13, 2004 at 09:05:50AM +0300, Muli Ben-Yehuda wrote:
> On Thu, May 13, 2004 at 03:55:20PM +1000, David Gibson wrote:
>
> > +++ working-2.6/mm/mmap.c 2004-04-27 13:40:01.062285976 +1000
> > @@ -21,6 +21,7 @@
> > #include <linux/profile.h>
> > #include <linux/module.h>
> > #include <linux/mount.h>
> > +#include <linux/err.h>
> >
> > #include <asm/uaccess.h>
> > #include <asm/pgalloc.h>
> > @@ -62,6 +63,9 @@
> > EXPORT_SYMBOL(sysctl_max_map_count);
> > EXPORT_SYMBOL(vm_committed_space);
> >
> > +int mmap_use_hugepages = 0;
> > +int mmap_hugepages_map_sz = 256;
>
> These two global variables do not appear to be used anywhere in this
> patch?

Bother, they leaked in there from the other patch I had on top of
this. Revised version below.

> > +static inline unsigned long __do_mmap_pgoff(struct file * file, unsigned long addr,
>
> __do_mmap_pgoff seems rather long to be inline?

Well, it's only called in one place - it's really the one function,
just split up to let us put the wrapper creating the hugetlb file in
the right place without excessive indentation. I guess it doesn't
really matter, with -funit-at-a-time it will end up the same anyway.

Add a new MAP_HUGETLB mmap() flag to easily request that a block of
anonymous memory come from hugepages.

Index: working-2.6/include/asm-i386/mman.h
===================================================================
--- working-2.6.orig/include/asm-i386/mman.h 2003-10-03 11:24:48.000000000 +1000
+++ working-2.6/include/asm-i386/mman.h 2004-05-13 14:51:18.698011208 +1000
@@ -16,6 +16,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed by hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-ppc64/mman.h
===================================================================
--- working-2.6.orig/include/asm-ppc64/mman.h 2003-10-01 11:47:33.000000000 +1000
+++ working-2.6/include/asm-ppc64/mman.h 2004-05-13 14:51:18.705010144 +1000
@@ -26,6 +26,7 @@
#define MAP_LOCKED 0x80

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */

Index: working-2.6/include/linux/mman.h
===================================================================
--- working-2.6.orig/include/linux/mman.h 2003-10-07 10:31:58.000000000 +1000
+++ working-2.6/include/linux/mman.h 2004-05-13 14:51:18.712009080 +1000
@@ -58,6 +58,9 @@
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
_calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
+#ifdef CONFIG_HUGETLB_PAGE
+ _calc_vm_trans(flags, MAP_HUGETLB, VM_HUGETLB ) |
+#endif
_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED );
}

Index: working-2.6/include/asm-sh/mman.h
===================================================================
--- working-2.6.orig/include/asm-sh/mman.h 2003-10-01 11:47:40.000000000 +1000
+++ working-2.6/include/asm-sh/mman.h 2004-05-13 14:51:18.718008168 +1000
@@ -16,6 +16,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-ia64/mman.h
===================================================================
--- working-2.6.orig/include/asm-ia64/mman.h 2004-01-28 10:55:18.000000000 +1100
+++ working-2.6/include/asm-ia64/mman.h 2004-05-13 14:51:18.721007712 +1000
@@ -24,6 +24,7 @@

#define MAP_GROWSDOWN 0x00100 /* stack-like segment */
#define MAP_GROWSUP 0x00200 /* register stack-like segment */
+#define MAP_HUGETLB 0x00400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x00800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x01000 /* mark it as an executable */
#define MAP_LOCKED 0x02000 /* pages are locked */
Index: working-2.6/include/asm-sparc64/mman.h
===================================================================
--- working-2.6.orig/include/asm-sparc64/mman.h 2003-10-01 11:47:45.000000000 +1000
+++ working-2.6/include/asm-sparc64/mman.h 2004-05-13 14:51:18.724007256 +1000
@@ -24,6 +24,7 @@
#define _MAP_NEW 0x80000000 /* Binary compatibility is fun... */

#define MAP_GROWSDOWN 0x0200 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */

Index: working-2.6/include/asm-x86_64/mman.h
===================================================================
--- working-2.6.orig/include/asm-x86_64/mman.h 2003-10-01 11:47:50.000000000 +1000
+++ working-2.6/include/asm-x86_64/mman.h 2004-05-13 14:51:18.726006952 +1000
@@ -17,6 +17,7 @@
#define MAP_32BIT 0x40 /* only give out 32bit addresses */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-ppc/mman.h
===================================================================
--- working-2.6.orig/include/asm-ppc/mman.h 2003-10-01 11:47:28.000000000 +1000
+++ working-2.6/include/asm-ppc/mman.h 2004-05-13 14:51:18.733005888 +1000
@@ -19,6 +19,7 @@
#define MAP_LOCKED 0x80

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
Index: working-2.6/include/asm-alpha/mman.h
===================================================================
--- working-2.6.orig/include/asm-alpha/mman.h 2003-10-01 11:46:52.000000000 +1000
+++ working-2.6/include/asm-alpha/mman.h 2004-05-13 14:51:18.735005584 +1000
@@ -28,6 +28,7 @@
#define MAP_NORESERVE 0x10000 /* don't check for reservations */
#define MAP_POPULATE 0x20000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x40000 /* do not block on IO */
+#define MAP_HUGETLB 0x80000 /* Backed with hugetlb pages */

#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_SYNC 2 /* synchronous memory sync */
Index: working-2.6/include/asm-arm/mman.h
===================================================================
--- working-2.6.orig/include/asm-arm/mman.h 2003-10-01 11:46:53.000000000 +1000
+++ working-2.6/include/asm-arm/mman.h 2004-05-13 14:51:18.741004672 +1000
@@ -16,6 +16,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-arm26/mman.h
===================================================================
--- working-2.6.orig/include/asm-arm26/mman.h 2003-10-01 11:47:01.000000000 +1000
+++ working-2.6/include/asm-arm26/mman.h 2004-05-13 14:51:18.744004216 +1000
@@ -16,6 +16,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-cris/mman.h
===================================================================
--- working-2.6.orig/include/asm-cris/mman.h 2003-10-01 11:47:02.000000000 +1000
+++ working-2.6/include/asm-cris/mman.h 2004-05-13 14:51:18.751003152 +1000
@@ -18,6 +18,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-h8300/mman.h
===================================================================
--- working-2.6.orig/include/asm-h8300/mman.h 2003-10-01 11:47:05.000000000 +1000
+++ working-2.6/include/asm-h8300/mman.h 2004-05-13 14:51:18.764001176 +1000
@@ -15,6 +15,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-m68k/mman.h
===================================================================
--- working-2.6.orig/include/asm-m68k/mman.h 2003-10-01 11:47:14.000000000 +1000
+++ working-2.6/include/asm-m68k/mman.h 2004-05-13 14:51:18.771000112 +1000
@@ -16,6 +16,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-mips/mman.h
===================================================================
--- working-2.6.orig/include/asm-mips/mman.h 2003-10-01 11:47:19.000000000 +1000
+++ working-2.6/include/asm-mips/mman.h 2004-05-13 14:51:18.779998744 +1000
@@ -38,6 +38,7 @@
#define MAP_AUTORSRV 0x100 /* Logical swap reserved on demand */

/* These are linux-specific */
+#define MAP_HUGETLB 0x0200 /* Backed with hugetlb pages */
#define MAP_NORESERVE 0x0400 /* don't check for reservations */
#define MAP_ANONYMOUS 0x0800 /* don't use a file */
#define MAP_GROWSDOWN 0x1000 /* stack-like segment */
Index: working-2.6/include/asm-parisc/mman.h
===================================================================
--- working-2.6.orig/include/asm-parisc/mman.h 2003-10-01 11:47:25.000000000 +1000
+++ working-2.6/include/asm-parisc/mman.h 2004-05-13 14:51:18.785997832 +1000
@@ -15,6 +15,7 @@
#define MAP_FIXED 0x04 /* Interpret addr exactly */
#define MAP_ANONYMOUS 0x10 /* don't use a file */

+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-s390/mman.h
===================================================================
--- working-2.6.orig/include/asm-s390/mman.h 2003-10-01 11:47:38.000000000 +1000
+++ working-2.6/include/asm-s390/mman.h 2004-05-13 14:51:18.791996920 +1000
@@ -24,6 +24,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/include/asm-sparc/mman.h
===================================================================
--- working-2.6.orig/include/asm-sparc/mman.h 2003-10-01 11:47:43.000000000 +1000
+++ working-2.6/include/asm-sparc/mman.h 2004-05-13 14:51:18.797996008 +1000
@@ -24,6 +24,7 @@
#define _MAP_NEW 0x80000000 /* Binary compatibility is fun... */

#define MAP_GROWSDOWN 0x0200 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */

Index: working-2.6/include/asm-v850/mman.h
===================================================================
--- working-2.6.orig/include/asm-v850/mman.h 2003-10-01 11:47:49.000000000 +1000
+++ working-2.6/include/asm-v850/mman.h 2004-05-13 14:51:18.803995096 +1000
@@ -15,6 +15,7 @@
#define MAP_ANONYMOUS 0x20 /* don't use a file */

#define MAP_GROWSDOWN 0x0100 /* stack-like segment */
+#define MAP_HUGETLB 0x0400 /* Backed with hugetlb pages */
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_LOCKED 0x2000 /* pages are locked */
Index: working-2.6/mm/mmap.c
===================================================================
--- working-2.6.orig/mm/mmap.c 2004-04-20 10:50:09.000000000 +1000
+++ working-2.6/mm/mmap.c 2004-05-13 16:13:58.213950408 +1000
@@ -21,6 +21,7 @@
#include <linux/profile.h>
#include <linux/module.h>
#include <linux/mount.h>
+#include <linux/err.h>

#include <asm/uaccess.h>
#include <asm/pgalloc.h>
@@ -476,13 +477,9 @@
return NULL;
}

-/*
- * The caller must hold down_write(current->mm->mmap_sem).
- */
-
-unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
- unsigned long len, unsigned long prot,
- unsigned long flags, unsigned long pgoff)
+static inline unsigned long __do_mmap_pgoff(struct file * file, unsigned long addr,
+ unsigned long len, unsigned long prot,
+ unsigned long flags, unsigned long pgoff)
{
struct mm_struct * mm = current->mm;
struct vm_area_struct * vma, * prev;
@@ -494,40 +491,19 @@
int accountable = 1;
unsigned long charged = 0;

- if (file) {
- if (is_file_hugepages(file))
- accountable = 0;
-
- if (!file->f_op || !file->f_op->mmap)
- return -ENODEV;
-
- if ((prot & PROT_EXEC) && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
- return -EPERM;
- }
-
- if (!len)
- return addr;
-
- /* Careful about overflows.. */
- len = PAGE_ALIGN(len);
- if (!len || len > TASK_SIZE)
- return -EINVAL;
-
- /* offset overflow? */
- if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
- return -EINVAL;
-
- /* Too many mappings? */
- if (mm->map_count > sysctl_max_map_count)
- return -ENOMEM;
-
- /* Obtain the address to map to. we verify (or select) it and ensure
- * that it represents a valid section of the address space.
+ /* Obtain the address to map to. we verify (or select) it and
+ * ensure that it represents a valid section of the address
+ * space. VM_HUGETLB will never appear in vm_flags when
+ * CONFIG_HUGETLB is unset.
*/
addr = get_unmapped_area(file, addr, len, pgoff, flags);
if (addr & ~PAGE_MASK)
return addr;

+ /* Huge pages aren't accounted for here */
+ if (file && is_file_hugepages(file))
+ accountable = 0;
+
/* Do simple checking here so the lower-level routines won't have
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
@@ -724,11 +700,17 @@
unmap_and_free_vma:
if (correct_wcount)
atomic_inc(&inode->i_writecount);
- vma->vm_file = NULL;
- fput(file);

- /* Undo any partial mapping done by a device driver. */
+ /*
+ * Undo any partial mapping done by a device driver.
+ * hugetlb wants to know the vma's file etc. so nuke
+ * the file afterward.
+ */
zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
+
+ if (file)
+ fput(vma->vm_file);
+
free_vma:
kmem_cache_free(vm_area_cachep, vma);
unacct_error:
@@ -737,6 +719,62 @@
return error;
}

+/*
+ * The caller must hold down_write(current->mm->mmap_sem).
+ */
+
+unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
+ unsigned long len, unsigned long prot,
+ unsigned long flags, unsigned long pgoff)
+{
+ struct file *hugetlb_file = NULL;
+ unsigned long result;
+
+ if (file) {
+ if ((flags & MAP_HUGETLB) && !is_file_hugepages(file))
+ return -EINVAL;
+
+ if (!file->f_op || !file->f_op->mmap)
+ return -ENODEV;
+
+ if ((prot & PROT_EXEC) && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
+ return -EPERM;
+ }
+
+ if (!len)
+ return addr;
+
+ /* Careful about overflows.. */
+ len = PAGE_ALIGN(len);
+ if (!len || len > TASK_SIZE)
+ return -EINVAL;
+
+ /* offset overflow? */
+ if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
+ return -EINVAL;
+
+ /* Too many mappings? */
+ if (current->mm->map_count > sysctl_max_map_count)
+ return -ENOMEM;
+
+ /* Create an implicit hugetlb file if necessary */
+ if (!file && (flags & MAP_HUGETLB)) {
+ file = hugetlb_file = hugetlb_zero_setup(len);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+ }
+
+ result = __do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+
+ /* Drop reference to implicit hugetlb file, it's already been
+ * "gotten" in __do_mmap_pgoff in case of success
+ */
+ if (hugetlb_file)
+ fput(hugetlb_file);
+
+ return result;
+}
+
EXPORT_SYMBOL(do_mmap_pgoff);

/* Get an address range which is currently unmapped.


--
David Gibson | For every complex problem there is a
david AT gibson.dropbear.id.au | solution which is simple, neat and
| wrong.
http://www.ozlabs.org/people/dgibson

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