[PATCH 2/3] Add MAP_HUGETLB for mmaping pseudo-anonymous huge page regions V2
From: Eric B Munson <hidden>
Date: 2009-08-13 09:57:07
Also in:
linux-mm
Subsystem:
generic include/asm header files, hugetlb subsystem, memory management, memory mapping, the rest · Maintainers:
Arnd Bergmann, Muchun Song, Oscar Salvador, Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
This patch adds a flag for mmap that will be used to request a huge page region that will look like anonymous memory to user space. This is accomplished by using a file on the internal vfsmount. MAP_HUGETLB is a modifier of MAP_ANONYMOUS and so must be specified with it. The region will behave the same as a MAP_ANONYMOUS region using small pages. Signed-off-by: Eric B Munson <redacted> --- Changes from V1 Rebase to newest linux-2.6 tree Rename MAP_LARGEPAGE to MAP_HUGETLB to match flag name for huge page shm include/asm-generic/mman-common.h | 1 + include/linux/hugetlb.h | 7 +++++++ mm/mmap.c | 16 ++++++++++++++++ 3 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/include/asm-generic/mman-common.h b/include/asm-generic/mman-common.h
index 3b69ad3..12f5982 100644
--- a/include/asm-generic/mman-common.h
+++ b/include/asm-generic/mman-common.h@@ -19,6 +19,7 @@ #define MAP_TYPE 0x0f /* Mask for type of mapping */ #define MAP_FIXED 0x10 /* Interpret addr exactly */ #define MAP_ANONYMOUS 0x20 /* don't use a file */ +#define MAP_HUGETLB 0x40 /* create a huge page mapping */ #define MS_ASYNC 1 /* sync memory asynchronously */ #define MS_INVALIDATE 2 /* invalidate the caches */
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 78b6ddf..b84361c 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h@@ -109,12 +109,19 @@ static inline void hugetlb_report_meminfo(struct seq_file *m) #endif /* !CONFIG_HUGETLB_PAGE */ +#define HUGETLB_ANON_FILE "anon_hugepage" + enum { /* * The file will be used as an shm file so shmfs accounting rules * apply */ HUGETLB_SHMFS_INODE = 0x01, + /* + * The file is being created on the internal vfs mount and shmfs + * accounting rules do not apply + */ + HUGETLB_ANONHUGE_INODE = 0x02, }; #ifdef CONFIG_HUGETLBFS
diff --git a/mm/mmap.c b/mm/mmap.c
index 34579b2..3612b20 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -29,6 +29,7 @@ #include <linux/rmap.h> #include <linux/mmu_notifier.h> #include <linux/perf_counter.h> +#include <linux/hugetlb.h> #include <asm/uaccess.h> #include <asm/cacheflush.h>
@@ -954,6 +955,21 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, if (mm->map_count > sysctl_max_map_count) return -ENOMEM; + if (flags & MAP_HUGETLB) { + if (file) + return -EINVAL; + + /* + * VM_NORESERVE is used because the reservations will be + * taken when vm_ops->mmap() is called + */ + len = ALIGN(len, huge_page_size(&default_hstate)); + file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE, + HUGETLB_ANONHUGE_INODE); + if (IS_ERR(file)) + 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. */
--
1.6.3.2
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