Re: [PATCH] MM: Support more pagesizes for MAP_HUGETLB/SHM_HUGETLB v5

From: Hillf Danton
Date: Sat Oct 13 2012 - 23:34:12 EST


Hi Andi,

On Sat, Oct 13, 2012 at 11:38 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> v2: Port to new tree. Fix unmount.
> v3: Ported to latest tree.
> v4: Ported to latest tree. Minor changes for review feedback. Updated
> description.
> v5: Remove unnecessary prototypes to fix merge error (Hillf Dalton)

s/Dalton/Danton/

> 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)
> + struct user_struct **user,
> + int creat_flags, int page_size_log)
> {
> int error = -ENOMEM;
> struct file *file;
> @@ -944,9 +957,14 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
> struct qstr quick_string;
> struct hstate *hstate;
> unsigned long num_pages;
> + int hstate_idx;
> +
> + hstate_idx = get_hstate_idx(page_size_log);
> + if (hstate_idx < 0)
> + return ERR_PTR(-ENODEV);
>
> *user = NULL;
> - if (!hugetlbfs_vfsmount)
> + if (!hugetlbfs_vfsmount[hstate_idx])

Maybe
if (IS_ERR(hugetlbfs_vfsmount[hstate_idx]))
since ...

> static int __init init_hugetlbfs_fs(void)
> {
> + struct hstate *h;
> int error;
> - struct vfsmount *vfsmount;
> + int i;
>
> error = bdi_init(&hugetlbfs_backing_dev_info);
> if (error)
> @@ -1029,14 +1048,26 @@ static int __init init_hugetlbfs_fs(void)
> if (error)
> goto out;
>
> - vfsmount = kern_mount(&hugetlbfs_fs_type);
> + i = 0;
> + for_each_hstate (h) {
> + char buf[50];
> + unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
>
> - if (!IS_ERR(vfsmount)) {
> - hugetlbfs_vfsmount = vfsmount;
> - return 0;
> - }
> + snprintf(buf, sizeof buf, "pagesize=%uK", ps_kb);
> + hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
> + buf);
>
> - error = PTR_ERR(vfsmount);
> + if (IS_ERR(hugetlbfs_vfsmount[i])) {
> + pr_err(
> + "hugetlb: Cannot mount internal hugetlbfs for page size %uK",
> + ps_kb);
> + error = PTR_ERR(hugetlbfs_vfsmount[i]);

... hugetlbfs_vfsmount[i] is not reset.

> + }
> + i++;
> + }
> + /* Non default hstates are optional */
> + if (hugetlbfs_vfsmount[default_hstate_idx])

ditto.

BTW, resetting looks simpler?

> + return 0;
--
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