On Fri, Nov 19, 2010 at 04:33:52PM -0700, Eric B Munson wrote:
> This patch adds a check for MAP_HUGETLB support and a flag in
> __hugetlb_opts for holding the availability.
>
> Signed-off-by: Eric B Munson <emun...@mgebm.net>
> ---
> hugeutils.c | 21 +++++++++++++++++++++
> init.c | 1 +
> libhugetlbfs_internal.h | 3 +++
> 3 files changed, 25 insertions(+), 0 deletions(-)
>
> diff --git a/hugeutils.c b/hugeutils.c
> index 3b442c3..646dea1 100644
> --- a/hugeutils.c
> +++ b/hugeutils.c
> @@ -340,6 +340,27 @@ void hugetlbfs_check_safe_noreserve()
> }
> }
>
> +void hugetlbfs_check_map_hugetlb()
> +{
> +/*
> + * FIXME: MAP_HUGETLB has not been picked up by glibc so even though the
> + * kernel may support it, without the userspace mmap flag it cannot be
> + * used. This ifdef should be removed when the MAP_HUGETLB flag makes it
> + * into glibc.
> + */
> +#ifdef MAP_HUGETLB
> + /*
> + * Kernels after 2.6.32 support mmaping pseudo-anonymous regions
> + * backed by huge pages, use this feature for huge pages we
> + * don't intend to share.
> + */
> + if (hugetlbfs_test_feature(HUGETLB_FEATURE_MAP_HUGETLB) > 0) {
> + INFO("Kernel supports MAP_HUGETLB\n");
> + __hugetlb_opts.map_hugetlb = 1;
> + }
> +#endif
> +}
> +
> /*
> * Pool counters are typically exposed in sysfs in modern kernels, the
> * counters for the default page size are exposed in procfs in all kernels
> diff --git a/init.c b/init.c
> index 049c9e2..c7f5a05 100644
> --- a/init.c
> +++ b/init.c
> @@ -27,6 +27,7 @@ static void __attribute__ ((constructor))
> setup_libhugetlbfs(void)
> setup_features();
> hugetlbfs_check_priv_resv();
> hugetlbfs_check_safe_noreserve();
> + hugetlbfs_check_map_hugetlb();
> #ifndef NO_ELFLINK
> hugetlbfs_setup_elflink();
> #endif
> diff --git a/libhugetlbfs_internal.h b/libhugetlbfs_internal.h
> index 6e9379e..ace64bd 100644
> --- a/libhugetlbfs_internal.h
> +++ b/libhugetlbfs_internal.h
> @@ -61,6 +61,7 @@ struct libhugeopts_t {
> int shrink_ok;
> int shm_enabled;
> int no_reserve;
> + int map_hugetlb;
> unsigned long force_elfmap;
Bah, just a side-note but some of these should have been bool, not int.
> char *ld_preload;
> char *elfmap;
> @@ -103,6 +104,8 @@ extern void setup_features();
> extern void hugetlbfs_check_priv_resv();
> #define hugetlbfs_check_safe_noreserve __lh_hugetlbfs_check_safe_noreserve
> extern void hugetlbfs_check_safe_noreserve();
> +#define hugetlbfs_check_map_hugetlb __lh_hugetblfs_check_map_hugetlb
> +extern void hugetlbfs_check_map_hugetlb();
> #define __hugetlbfs_hostname __lh___hugetlbfs_hostname
> extern char __hugetlbfs_hostname[];
> #define hugetlbfs_prefault __lh_hugetlbfs_prefault
Otherwise;
Acked-by: Mel Gorman <m...@csn.ul.ie>
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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