On Wed 16-11-16 14:53:02, Huang Shijie wrote:
> This patch intruduces a new helper huge_nodemask(),
> we can use it to get the node mask.
>
> This idea of the function is from the init_nodemask_of_mempolicy():
> Return true if we can succeed in extracting the node_mask
> for 'bind' or 'interleave' policy or initializing the node_mask
> to contain the single node for 'preferred' or 'local' policy.
It is absolutely unclear how this is going to be used from this patch.
Please make sure to also use a newly added function in the same patch.
>
> Signed-off-by: Huang Shijie <shijie.huang@xxxxxxx>
> ---
> The previous version does not treat the MPOL_PREFERRED/MPOL_INTERLEAVE cases.
> This patch adds the code to set proper node mask for
> MPOL_PREFERRED/MPOL_INTERLEAVE.
> ---
> include/linux/mempolicy.h | 8 ++++++++
> mm/mempolicy.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+)
>
> diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
> index 5e5b296..7796a40 100644
> --- a/include/linux/mempolicy.h
> +++ b/include/linux/mempolicy.h
> @@ -145,6 +145,8 @@ extern void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
> enum mpol_rebind_step step);
> extern void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new);
>
> +extern bool huge_nodemask(struct vm_area_struct *vma,
> + unsigned long addr, nodemask_t *mask);
> extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
> unsigned long addr, gfp_t gfp_flags,
> struct mempolicy **mpol, nodemask_t **nodemask);
> @@ -261,6 +263,12 @@ static inline void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
> {
> }
>
> +static inline bool huge_nodemask(struct vm_area_struct *vma,
> + unsigned long addr, nodemask_t *mask)
> +{
> + return false;
> +}
> +
> static inline struct zonelist *huge_zonelist(struct vm_area_struct *vma,
> unsigned long addr, gfp_t gfp_flags,
> struct mempolicy **mpol, nodemask_t **nodemask)
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 6d3639e..5063a69 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1800,6 +1800,53 @@ static inline unsigned interleave_nid(struct mempolicy *pol,
>
> #ifdef CONFIG_HUGETLBFS
> /*
> + * huge_nodemask(@vma, @addr, @mask)
> + * @vma: virtual memory area whose policy is sought
> + * @addr: address in @vma
> + * @mask: a nodemask pointer
> + *
> + * Return true if we can succeed in extracting the policy nodemask
> + * for 'bind' or 'interleave' policy into the argument @mask, or
> + * initializing the argument @mask to contain the single node for
> + * 'preferred' or 'local' policy.
> + */
> +bool huge_nodemask(struct vm_area_struct *vma, unsigned long addr,
> + nodemask_t *mask)
> +{
> + struct mempolicy *mpol;
> + bool ret = true;
> + int nid;
> +
> + if (!mask)
> + return false;
> +
> + mpol = get_vma_policy(vma, addr);
> +
> + switch (mpol->mode) {
> + case MPOL_PREFERRED:
> + if (mpol->flags & MPOL_F_LOCAL)
> + nid = numa_node_id();
> + else
> + nid = mpol->v.preferred_node;
> + init_nodemask_of_node(mask, nid);
> + break;
> +
> + case MPOL_BIND:
> + /* Fall through */
> + case MPOL_INTERLEAVE:
> + *mask = mpol->v.nodes;
> + break;
> +
> + default:
> + ret = false;
> + break;
> + }
> + mpol_cond_put(mpol);
> +
> + return ret;
> +}
> +
> +/*
> * huge_zonelist(@vma, @addr, @gfp_flags, @mpol)
> * @vma: virtual memory area whose policy is sought
> * @addr: address in @vma for shared policy lookup and interleave policy
> --
> 2.5.5
>
--
Michal Hocko
SUSE Labs
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