On Wed, Apr 24, 2013 at 04:14:54AM -0400, Johannes Weiner wrote:
> On Tue, Apr 23, 2013 at 01:25:22PM -0700, Andrew Morton wrote:
...
> hugetlb_get_unmapped_area() expects a hugepage-aligned size argument.
> Before do_mmap_pgoff() calls it, it does len = PAGE_ALIGN(len), which
> is why the second case works and the first one does not.
>
> How about this (untested) partial revert of the above patch that keeps
> the shm alignment fix?
I have one comment about the suggested patch.
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 84e3d85..13a7d51 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -929,9 +929,8 @@ static struct dentry_operations anon_ops = {
> .d_dname = hugetlb_dname
> };
>
> -struct file *hugetlb_file_setup(const char *name, unsigned long addr,
> - size_t size, vm_flags_t acctflag,
> - struct user_struct **user,
> +struct file *hugetlb_file_setup(const char *name, size_t size,
> + vm_flags_t acctflag, struct user_struct **user,
> int creat_flags, int page_size_log)
> {
> struct file *file = ERR_PTR(-ENOMEM);
> @@ -939,8 +938,6 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
> struct path path;
> struct super_block *sb;
> struct qstr quick_string;
> - struct hstate *hstate;
> - unsigned long num_pages;
> int hstate_idx;
>
> hstate_idx = get_hstate_idx(page_size_log);
> @@ -980,12 +977,10 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
> if (!inode)
> goto out_dentry;
>
> - hstate = hstate_inode(inode);
> - size += addr & ~huge_page_mask(hstate);
> - num_pages = ALIGN(size, huge_page_size(hstate)) >>
> - huge_page_shift(hstate);
> file = ERR_PTR(-ENOMEM);
> - if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
> + if (hugetlb_reserve_pages(inode, 0,
> + size >> huge_page_shift(hstate_inode(inode)), NULL,
> + acctflag))
> goto out_inode;
>
> d_instantiate(path.dentry, inode);
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 16e4e9a..437875c 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -185,8 +185,7 @@ static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
>
> extern const struct file_operations hugetlbfs_file_operations;
> extern const struct vm_operations_struct hugetlb_vm_ops;
> -struct file *hugetlb_file_setup(const char *name, unsigned long addr,
> - size_t size, vm_flags_t acct,
> +struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct,
> struct user_struct **user, int creat_flags,
> int page_size_log);
>
> @@ -205,9 +204,9 @@ static inline int is_file_hugepages(struct file *file)
>
> #define is_file_hugepages(file) 0
> static inline struct file *
> -hugetlb_file_setup(const char *name, unsigned long addr, size_t size,
> - vm_flags_t acctflag, struct user_struct **user, int creat_flags,
> - int page_size_log)
> +hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
> + struct user_struct **user, int creat_flags,
> + int page_size_log)
> {
> return ERR_PTR(-ENOSYS);
> }
> diff --git a/ipc/shm.c b/ipc/shm.c
> index cb858df..c1293d1 100644
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -491,10 +491,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
>
> sprintf (name, "SYSV%08x", key);
> if (shmflg & SHM_HUGETLB) {
> + unsigned int hugesize;
> +
> /* hugetlb_file_setup applies strict accounting */
> if (shmflg & SHM_NORESERVE)
> acctflag = VM_NORESERVE;
> - file = hugetlb_file_setup(name, 0, size, acctflag,
> + hugesize = ALIGN(size, huge_page_size(&default_hstate));
> + file = hugetlb_file_setup(name, hugesize, acctflag,
> &shp->mlock_user, HUGETLB_SHMFS_INODE,
> (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
> } else {
Would it be better to find proper hstate instead of using default_hstate?
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 6466699..36342dd 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1335,7 +1335,8 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
> * A dummy user value is used because we are not locking
> * memory so no accounting is necessary
> */
> - file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len,
> + len = ALIGN(len, huge_page_size(&default_hstate));
> + file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
> VM_NORESERVE,
> &user, HUGETLB_ANONHUGE_INODE,
> (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
>
ditto.
Thanks,
Naoya Horiguchi
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