On Tue, Mar 22, 2016 at 03:30:43PM +0530, Vaishali Thakkar wrote:
> When any unsupported hugepage size is specified, 'hugepagesz=' and
> 'hugepages=' should be ignored during command line parsing until any
> supported hugepage size is found. But currently incorrect number of
> hugepages are allocated when unsupported size is specified as it fails
> to ignore the 'hugepages=' command.
>
> Test case:
>
> Note that this is specific to x86 architecture.
>
> Boot the kernel with command line option 'hugepagesz=256M hugepages=X'.
> After boot, dmesg output shows that X number of hugepages of the size 2M
> is pre-allocated instead of 0.
>
> So, to handle such command line options, introduce new routine
> hugetlb_bad_size. The routine hugetlb_bad_size sets the global variable
> parsed_valid_hugepagesz. We are using parsed_valid_hugepagesz to save the
> state when unsupported hugepagesize is found so that we can ignore the
> 'hugepages=' parameters after that and then reset the variable when
> supported hugepage size is found.
>
> The routine hugetlb_bad_size can be called while setting 'hugepagesz='
> parameter in an architecture specific code.
> Signed-off-by: Vaishali Thakkar <vaishali.thakkar@xxxxxxxxxx>
> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Yaowei Bai <baiyaowei@xxxxxxxxxxxxxxxxxxxx>
> Cc: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Maybe parsed_hstate can do what parsed_valid_hugepagesz does, but both
are __initdata so it's not a big deal.
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
> The patch is having 2 checkpatch.pl warnings. I have just followed
> the current code to maintain consistency. If we decide to silent
> these warnings then may be we should silent those warnings as well.
> I am fine with any option whichever works best for everyone else.
> ---
> include/linux/hugetlb.h | 1 +
> mm/hugetlb.c | 14 +++++++++++++-
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 7d953c2..e44c578 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -338,6 +338,7 @@ int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
> /* arch callback */
> int __init alloc_bootmem_huge_page(struct hstate *h);
>
> +void __init hugetlb_bad_size(void);
> void __init hugetlb_add_hstate(unsigned order);
> struct hstate *size_to_hstate(unsigned long size);
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 06058ea..44fae6a 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -51,6 +51,7 @@ __initdata LIST_HEAD(huge_boot_pages);
> static struct hstate * __initdata parsed_hstate;
> static unsigned long __initdata default_hstate_max_huge_pages;
> static unsigned long __initdata default_hstate_size;
> +static bool __initdata parsed_valid_hugepagesz = true;
>
> /*
> * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
> @@ -2659,6 +2660,11 @@ static int __init hugetlb_init(void)
> subsys_initcall(hugetlb_init);
>
> /* Should be called on processing a hugepagesz=... option */
> +void __init hugetlb_bad_size(void)
> +{
> + parsed_valid_hugepagesz = false;
> +}
> +
> void __init hugetlb_add_hstate(unsigned int order)
> {
> struct hstate *h;
> @@ -2691,11 +2697,17 @@ static int __init hugetlb_nrpages_setup(char *s)
> unsigned long *mhp;
> static unsigned long *last_mhp;
>
> + if (!parsed_valid_hugepagesz) {
> + pr_warn("hugepages = %s preceded by "
> + "an unsupported hugepagesz, ignoring\n", s);
> + parsed_valid_hugepagesz = true;
> + return 1;
> + }
> /*
> * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
> * so this hugepages= parameter goes to the "default hstate".
> */
> - if (!hugetlb_max_hstate)
> + else if (!hugetlb_max_hstate)
> mhp = &default_hstate_max_huge_pages;
> else
> mhp = &parsed_hstate->max_huge_pages;
> --
> 2.1.4
>
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