lkml.org 
[lkml]   [2012]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] Correct alignment of huge page requests.
Date
When calling shmget() with SHM_HUGETLB, shmget aligns the request size to PAGE_SIZE, but this is not sufficient.  Modified hugetlb_file_setup() to align requests to the huge page size.  Also modified mmap_pgoff() to avoid duplicating this check and to align against the start address.

Signed-off-by: Steven Truelove <steven.truelove@utoronto.ca>
---
fs/hugetlbfs/inode.c | 9 ++++++---
mm/mmap.c | 6 +++++-
2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 1e85a7a..b4bed46 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -938,6 +938,8 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
struct path path;
struct dentry *root;
struct qstr quick_string;
+ struct hstate *hstate;
+ int num_pages;

*user = NULL;
if (!hugetlbfs_vfsmount)
@@ -967,10 +969,11 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
if (!inode)
goto out_dentry;

+ hstate = hstate_inode(inode);
+ num_pages = ALIGN(size, huge_page_size(hstate)) >>
+ huge_page_shift(hstate);
error = -ENOMEM;
- if (hugetlb_reserve_pages(inode, 0,
- size >> huge_page_shift(hstate_inode(inode)), NULL,
- acctflag))
+ if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
goto out_inode;

d_instantiate(path.dentry, inode);
diff --git a/mm/mmap.c b/mm/mmap.c
index 3f758c7..1f44ccf 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1098,8 +1098,12 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
* taken when vm_ops->mmap() is called
* A dummy user value is used because we are not locking
* memory so no accounting is necessary
+ * Length is increased by the amount necessary to align
+ * the base address to the huge page size.
+ * hugetlb_file_setup() aligns the end of the buffer to
+ * the huge page size.
*/
- len = ALIGN(len, huge_page_size(&default_hstate));
+ len += ALIGN(addr, huge_page_size(&default_hstate)) - addr;
file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
&user, HUGETLB_ANONHUGE_INODE);
if (IS_ERR(file))
--
1.7.3.4


\
 
 \ /
  Last update: 2012-02-28 05:03    [W:0.029 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site