On Fri, 17 Feb 2012 13:22:44 +0800, bill4carson <bill4carson@xxxxxxxxx> wrote:
>
>
> On 2012年02月11日 05:36, Aneesh Kumar K.V wrote:
> > From: "Aneesh Kumar K.V"<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> >
> > HugeTLB controller is different from a memory controller in that we charge
> > controller during mmap() time and not fault time. This make sure userspace
> > can fallback to non-hugepage allocation when mmap fails due to controller
> > limit.
> >
> > For private mapping we always charge/uncharge from the current task cgroup.
> > Charging happens during mmap(2) and uncharge happens during the
> > vm_operations->close when resv_map refcount reaches zero. The uncharge count
> > is stored in struct resv_map. For child task after fork the charging happens
> > during fault time in alloc_huge_page. We also need to make sure for private
> > mapping each vma for hugeTLB mapping have struct resv_map allocated so that we
> > can store the uncharge count in resv_map.
> >
> > Signed-off-by: Aneesh Kumar K.V<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> > ---
> > fs/hugetlbfs/hugetlb_cgroup.c | 50 ++++++++++++++++++++++++++++++++
> > include/linux/hugetlb.h | 7 ++++
> > include/linux/hugetlb_cgroup.h | 16 ++++++++++
> > mm/hugetlb.c | 62 ++++++++++++++++++++++++++++++++--------
> > 4 files changed, 123 insertions(+), 12 deletions(-)
> >
> > diff --git a/fs/hugetlbfs/hugetlb_cgroup.c b/fs/hugetlbfs/hugetlb_cgroup.c
> > index c478fb0..f828fb2 100644
> > --- a/fs/hugetlbfs/hugetlb_cgroup.c
> > +++ b/fs/hugetlbfs/hugetlb_cgroup.c
> > @@ -458,3 +458,53 @@ long hugetlb_truncate_cgroup_charge(struct hstate *h,
> > }
> > return chg;
> > }
> > +
> > +int hugetlb_priv_page_charge(struct resv_map *map, struct hstate *h, long chg)
> > +{
> > + long csize;
> > + int idx, ret;
> > + struct hugetlb_cgroup *h_cg;
> > + struct res_counter *fail_res;
> > +
> > + /*
> > + * Get the task cgroup within rcu_readlock and also
> > + * get cgroup reference to make sure cgroup destroy won't
> > + * race with page_charge. We don't allow a cgroup destroy
> > + * when the cgroup have some charge against it
> > + */
> > + rcu_read_lock();
> > + h_cg = task_hugetlbcgroup(current);
> > + css_get(&h_cg->css);
> > + rcu_read_unlock();
> > +
> > + if (hugetlb_cgroup_is_root(h_cg)) {
> > + ret = chg;
> > + goto err_out;
> > + }
> > +
> > + csize = chg * huge_page_size(h);
> > + idx = h - hstates;
> > + ret = res_counter_charge(&h_cg->memhuge[idx], csize,&fail_res);
> > + if (!ret) {
> > + map->nr_pages[idx] += chg<< huge_page_order(h);
> > + ret = chg;
> > + }
> > +err_out:
> > + css_put(&h_cg->css);
> > + return ret;
> > +}
> > +
> > +void hugetlb_priv_page_uncharge(struct resv_map *map, int idx, int nr_pages)
> > +{
> > + struct hugetlb_cgroup *h_cg;
> > + unsigned long csize = nr_pages * PAGE_SIZE;
> > +
> > + rcu_read_lock();
> > + h_cg = task_hugetlbcgroup(current);
> > + if (!hugetlb_cgroup_is_root(h_cg)) {
> > + res_counter_uncharge(&h_cg->memhuge[idx], csize);
> > + map->nr_pages[idx] -= nr_pages;
> > + }
> > + rcu_read_unlock();
> > + return;
> > +}
> > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> > index 4392b6a..e2ba381 100644
> > --- a/include/linux/hugetlb.h
> > +++ b/include/linux/hugetlb.h
> > @@ -233,6 +233,12 @@ struct hstate {
> > char name[HSTATE_NAME_LEN];
> > };
> >
> > +struct resv_map {
> > + struct kref refs;
> > + int nr_pages[HUGE_MAX_HSTATE];
> > + struct list_head regions;
> > +};
> > +
>
> Please put resv_map after HUGE_MAX_HSTATE definition,
> otherwise it will break on non-x86 arches, which has no
> HUGE_MAX_HSTATE definition.
>
>
> #ifndef HUGE_MAX_HSTATE
> #define HUGE_MAX_HSTATE 1
> #endif
>
> +struct resv_map {
> + struct kref refs;
> + int nr_pages[HUGE_MAX_HSTATE];
> + struct list_head regions;
> +};
>
>
>
>
Will do in the next iteration.
Thanks for the review
-aneesh
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