On Mon, 27 Feb 2012 09:09:28 -0500 Steven Truelove <steven.truelove@xxxxxxxxxxx> wrote: > 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. > > Signed-off-by: Steven Truelove <steven.truelove@xxxxxxxxxxx> > --- > fs/hugetlbfs/inode.c | 9 ++++++--- > 1 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 1e85a7a..6c23f09 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 = (size + huge_page_size(hstate) - 1) >> > + 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); A few things... - sys_mmap_pgoff() does the rounding up prior to calling hugetlb_file_setup(). ipc/shm.c:newseg() does not. We should be consistent here: do it in the caller or the callee, not both (or neither!). I guess doing it in the callee would be best. - The above code could/should have used ALIGN(). Or round_up(): the difference presently escapes me, even though it was so obvious that we left all these things undocumented. - What's the point in aligning the length if we don't also look at the start address? If that isn't a multiple of huge_page_size(), we will need an additional page. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>