On Mon, 5 Oct 2009, Lee Schermerhorn wrote:
> Index: linux-2.6.31-mmotm-090925-1435/mm/mempolicy.c
> ===================================================================
> --- linux-2.6.31-mmotm-090925-1435.orig/mm/mempolicy.c 2009-09-30 12:48:45.000000000 -0400
> +++ linux-2.6.31-mmotm-090925-1435/mm/mempolicy.c 2009-09-30 12:48:46.000000000 -0400
> @@ -1564,6 +1564,53 @@ struct zonelist *huge_zonelist(struct vm
> }
> return zl;
> }
> +
> +/*
> + * init_nodemask_of_mempolicy
> + *
> + * If the current task's mempolicy is "default" [NULL], return 'false'
> + * to indicate * default policy. Otherwise, extract the policy nodemask
> + * for 'bind' * or 'interleave' policy into the argument nodemask, or
> + * initialize the argument nodemask to contain the single node for
> + * 'preferred' or * 'local' policy and return 'true' to indicate presence
> + * of non-default mempolicy.
> + *
Looks like some mangling of the comment, there's spurious '*' throughout.
> + * We don't bother with reference counting the mempolicy [mpol_get/put]
> + * because the current task is examining it's own mempolicy and a task's
> + * mempolicy is only ever changed by the task itself.
> + *
> + * N.B., it is the caller's responsibility to free a returned nodemask.
> + */
> +bool init_nodemask_of_mempolicy(nodemask_t *mask)
> +{
> + struct mempolicy *mempolicy;
> + int nid;
> +
> + if (!current->mempolicy)
> + return false;
> +
> + mempolicy = current->mempolicy;
> + switch (mempolicy->mode) {
> + case MPOL_PREFERRED:
> + if (mempolicy->flags & MPOL_F_LOCAL)
> + nid = numa_node_id();
> + else
> + nid = mempolicy->v.preferred_node;
> + init_nodemask_of_node(mask, nid);
> + break;
> +
> + case MPOL_BIND:
> + /* Fall through */
> + case MPOL_INTERLEAVE:
> + *mask = mempolicy->v.nodes;
> + break;
> +
> + default:
> + BUG();
> + }
> +
> + return true;
> +}
> #endif
>
> /* Allocate a page in interleaved policy.
> Index: linux-2.6.31-mmotm-090925-1435/include/linux/mempolicy.h
> ===================================================================
> --- linux-2.6.31-mmotm-090925-1435.orig/include/linux/mempolicy.h 2009-09-30 12:48:45.000000000 -0400
> +++ linux-2.6.31-mmotm-090925-1435/include/linux/mempolicy.h 2009-09-30 12:48:46.000000000 -0400
> @@ -201,6 +201,7 @@ extern void mpol_fix_fork_child_flag(str
> extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
> unsigned long addr, gfp_t gfp_flags,
> struct mempolicy **mpol, nodemask_t **nodemask);
> +extern bool init_nodemask_of_mempolicy(nodemask_t *mask);
> extern unsigned slab_node(struct mempolicy *policy);
>
> extern enum zone_type policy_zone;
> @@ -328,6 +329,8 @@ static inline struct zonelist *huge_zone
> return node_zonelist(0, gfp_flags);
> }
>
> +static inline bool init_nodemask_of_mempolicy(nodemask_t *m) { return false; }
> +
> static inline int do_migrate_pages(struct mm_struct *mm,
> const nodemask_t *from_nodes,
> const nodemask_t *to_nodes, int flags)
> Index: linux-2.6.31-mmotm-090925-1435/mm/hugetlb.c
> ===================================================================
> --- linux-2.6.31-mmotm-090925-1435.orig/mm/hugetlb.c 2009-09-30 12:48:45.000000000 -0400
> +++ linux-2.6.31-mmotm-090925-1435/mm/hugetlb.c 2009-10-02 21:22:04.000000000 -0400
> @@ -1334,29 +1334,71 @@ static struct hstate *kobj_to_hstate(str
> return NULL;
> }
>
> -static ssize_t nr_hugepages_show(struct kobject *kobj,
> +static ssize_t nr_hugepages_show_common(struct kobject *kobj,
> struct kobj_attribute *attr, char *buf)
> {
> struct hstate *h = kobj_to_hstate(kobj);
> return sprintf(buf, "%lu\n", h->nr_huge_pages);
> }
> -static ssize_t nr_hugepages_store(struct kobject *kobj,
> - struct kobj_attribute *attr, const char *buf, size_t count)
> +static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
> + struct kobject *kobj, struct kobj_attribute *attr,
> + const char *buf, size_t len)
> {
> int err;
> - unsigned long input;
> + unsigned long count;
> struct hstate *h = kobj_to_hstate(kobj);
> + NODEMASK_ALLOC(nodemask, nodes_allowed);
>
In the two places you do NODEMASK_ALLOC(), here and
hugetlb_sysctl_handler(), you'll need to check that nodes_allowed is
non-NULL since it's possible that kmalloc() will return NULL for
CONFIG_NODES_SHIFT > 8.
In such a case, it's probably sufficient to simply set nodes_allowed to
node_states[N_HIGH_MEMORY] so that we can still free hugepages when we're
oom, a common memory freeing tactic.
You could do that by simply returning false from
init_nodemask_of_mempolicy() if !nodes_allowed since NODEMASK_FREE() can
take a NULL pointer, but it may be easier to factor that logic into your
conditional below:
> - err = strict_strtoul(buf, 10, &input);
> + err = strict_strtoul(buf, 10, &count);
> if (err)
> return 0;
>
> - h->max_huge_pages = set_max_huge_pages(h, input, &node_online_map);
> + if (!(obey_mempolicy && init_nodemask_of_mempolicy(nodes_allowed))) {
> + NODEMASK_FREE(nodes_allowed);
> + nodes_allowed = &node_online_map;
> + }
> + h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
>
You can get away with just testing !nodes_allowed here since the stack
allocation variation of NODEMASK_ALLOC() is such that nodes_allowed will
always be an initialized pointer pointing to _nodes_allowed so you won't
have an uninitialized warning.
Once that's done, you can get rid of the check for a NULL nodes_allowed in
try_to_free_low() from patch 2 since it will always be valid in
set_max_huge_pages().
> - return count;
> + if (nodes_allowed != &node_online_map)
> + NODEMASK_FREE(nodes_allowed);
> +
> + return len;
> +}
> +
> +static ssize_t nr_hugepages_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + return nr_hugepages_show_common(kobj, attr, buf);
> +}
> +
> +static ssize_t nr_hugepages_store(struct kobject *kobj,
> + struct kobj_attribute *attr, const char *buf, size_t len)
> +{
> + return nr_hugepages_store_common(false, kobj, attr, buf, len);
> }
> HSTATE_ATTR(nr_hugepages);
>
> +#ifdef CONFIG_NUMA
> +
> +/*
> + * hstate attribute for optionally mempolicy-based constraint on persistent
> + * huge page alloc/free.
> + */
> +static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + return nr_hugepages_show_common(kobj, attr, buf);
> +}
> +
> +static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
> + struct kobj_attribute *attr, const char *buf, size_t len)
> +{
> + return nr_hugepages_store_common(true, kobj, attr, buf, len);
> +}
> +HSTATE_ATTR(nr_hugepages_mempolicy);
> +#endif
> +
> +
> static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
> struct kobj_attribute *attr, char *buf)
> {
> @@ -1412,6 +1454,9 @@ static struct attribute *hstate_attrs[]
> &free_hugepages_attr.attr,
> &resv_hugepages_attr.attr,
> &surplus_hugepages_attr.attr,
> +#ifdef CONFIG_NUMA
> + &nr_hugepages_mempolicy_attr.attr,
> +#endif
> NULL,
> };
>
> @@ -1578,9 +1623,9 @@ static unsigned int cpuset_mems_nr(unsig
> }
>
> #ifdef CONFIG_SYSCTL
> -int hugetlb_sysctl_handler(struct ctl_table *table, int write,
> - void __user *buffer,
> - size_t *length, loff_t *ppos)
> +static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
> + struct ctl_table *table, int write,
> + void __user *buffer, size_t *length, loff_t *ppos)
> {
> struct hstate *h = &default_hstate;
> unsigned long tmp;
> @@ -1592,13 +1637,39 @@ int hugetlb_sysctl_handler(struct ctl_ta
> table->maxlen = sizeof(unsigned long);
> proc_doulongvec_minmax(table, write, buffer, length, ppos);
>
> - if (write)
> - h->max_huge_pages = set_max_huge_pages(h, tmp,
> - &node_online_map);
> + if (write) {
> + NODEMASK_ALLOC(nodemask, nodes_allowed);
> + if (!(obey_mempolicy &&
> + init_nodemask_of_mempolicy(nodes_allowed))) {
> + NODEMASK_FREE(nodes_allowed);
> + nodes_allowed = &node_states[N_HIGH_MEMORY];
> + }
> + h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
> +
> + if (nodes_allowed != &node_states[N_HIGH_MEMORY])
> + NODEMASK_FREE(nodes_allowed);
> + }
>
> return 0;
> }
>
> +int hugetlb_sysctl_handler(struct ctl_table *table, int write,
> + void __user *buffer, size_t *length, loff_t *ppos)
> +{
> +
> + return hugetlb_sysctl_handler_common(false, table, write,
> + buffer, length, ppos);
> +}
> +
> +#ifdef CONFIG_NUMA
> +int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
> + void __user *buffer, size_t *length, loff_t *ppos)
> +{
> + return hugetlb_sysctl_handler_common(true, table, write,
> + buffer, length, ppos);
> +}
> +#endif /* CONFIG_NUMA */
> +
> int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
> void __user *buffer,
> size_t *length, loff_t *ppos)
> Index: linux-2.6.31-mmotm-090925-1435/include/linux/hugetlb.h
> ===================================================================
> --- linux-2.6.31-mmotm-090925-1435.orig/include/linux/hugetlb.h 2009-09-30 12:48:45.000000000 -0400
> +++ linux-2.6.31-mmotm-090925-1435/include/linux/hugetlb.h 2009-09-30 12:48:46.000000000 -0400
> @@ -23,6 +23,12 @@ void reset_vma_resv_huge_pages(struct vm
> int hugetlb_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
> int hugetlb_overcommit_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
> int hugetlb_treat_movable_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
> +
> +#ifdef CONFIG_NUMA
> +int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int,
> + void __user *, size_t *, loff_t *);
> +#endif
> +
> int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
> int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
> struct page **, struct vm_area_struct **,
> Index: linux-2.6.31-mmotm-090925-1435/kernel/sysctl.c
> ===================================================================
> --- linux-2.6.31-mmotm-090925-1435.orig/kernel/sysctl.c 2009-09-30 12:48:45.000000000 -0400
> +++ linux-2.6.31-mmotm-090925-1435/kernel/sysctl.c 2009-09-30 12:48:46.000000000 -0400
> @@ -1164,7 +1164,7 @@ static struct ctl_table vm_table[] = {
> .extra2 = &one_hundred,
> },
> #ifdef CONFIG_HUGETLB_PAGE
> - {
> + {
> .procname = "nr_hugepages",
> .data = NULL,
> .maxlen = sizeof(unsigned long),
> @@ -1172,7 +1172,19 @@ static struct ctl_table vm_table[] = {
> .proc_handler = &hugetlb_sysctl_handler,
> .extra1 = (void *)&hugetlb_zero,
> .extra2 = (void *)&hugetlb_infinity,
> - },
> + },
> +#ifdef CONFIG_NUMA
> + {
> + .ctl_name = CTL_UNNUMBERED,
> + .procname = "nr_hugepages_mempolicy",
> + .data = NULL,
> + .maxlen = sizeof(unsigned long),
> + .mode = 0644,
> + .proc_handler = &hugetlb_mempolicy_sysctl_handler,
> + .extra1 = (void *)&hugetlb_zero,
> + .extra2 = (void *)&hugetlb_infinity,
> + },
> +#endif
> {
> .ctl_name = VM_HUGETLB_GROUP,
> .procname = "hugetlb_shm_group",
>
There's some whitespace damage in the nr_hugepages_mempolicy hunk, it
needs tabs instead of spaces for alignment.
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