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hugetlb_cgroup: add reservation accounting for private mappings

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Normally the pointer to the cgroup to uncharge hangs off the struct page,
and gets queried when it's time to free the page.  With hugetlb_cgroup
reservations, this is not possible.  Because it's possible for a page to
be reserved by one task and actually faulted in by another task.

The best place to put the hugetlb_cgroup pointer to uncharge for
reservations is in the resv_map.  But, because the resv_map has different
semantics for private and shared mappings, the code patch to
charge/uncharge shared and private mappings is different.  This patch
implements charging and uncharging for private mappings.

For private mappings, the counter to uncharge is in
resv_map->reservation_counter.  On initializing the resv_map this is set
to NULL.  On reservation of a region in private mapping, the tasks
hugetlb_cgroup is charged and the hugetlb_cgroup is placed is
resv_map->reservation_counter.

On hugetlb_vm_op_close, we uncharge resv_map->reservation_counter.

[akpm@linux-foundation.org: forward declare struct resv_map]
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-3-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mina Almasry 2020-04-01 21:11:21 -07:00 committed by Linus Torvalds
parent 9808895e1a
commit e9fe92ae0c
4 changed files with 99 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/hugetlb.h
View File

@ -46,6 +46,16 @@ struct resv_map {
long adds_in_progress;
struct list_head region_cache;
long region_cache_count;
#ifdef CONFIG_CGROUP_HUGETLB
/*
* On private mappings, the counter to uncharge reservations is stored
* here. If these fields are 0, then either the mapping is shared, or
* cgroup accounting is disabled for this resv_map.
*/
struct page_counter *reservation_counter;
unsigned long pages_per_hpage;
struct cgroup_subsys_state *css;
#endif
};
extern struct resv_map *resv_map_alloc(void);
void resv_map_release(struct kref *ref);

41
include/linux/hugetlb_cgroup.h
View File

@ -18,6 +18,8 @@
#include <linux/mmdebug.h>
struct hugetlb_cgroup;
struct resv_map;
/*
* Minimum page order trackable by hugetlb cgroup.
* At least 4 pages are necessary for all the tracking information.
@ -27,6 +29,33 @@ struct hugetlb_cgroup;
#define HUGETLB_CGROUP_MIN_ORDER 2
#ifdef CONFIG_CGROUP_HUGETLB
enum hugetlb_memory_event {
HUGETLB_MAX,
HUGETLB_NR_MEMORY_EVENTS,
};
struct hugetlb_cgroup {
struct cgroup_subsys_state css;
/*
* the counter to account for hugepages from hugetlb.
*/
struct page_counter hugepage[HUGE_MAX_HSTATE];
/*
* the counter to account for hugepage reservations from hugetlb.
*/
struct page_counter rsvd_hugepage[HUGE_MAX_HSTATE];
atomic_long_t events[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS];
atomic_long_t events_local[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS];
/* Handle for "hugetlb.events" */
struct cgroup_file events_file[HUGE_MAX_HSTATE];
/* Handle for "hugetlb.events.local" */
struct cgroup_file events_local_file[HUGE_MAX_HSTATE];
};
static inline struct hugetlb_cgroup *
__hugetlb_cgroup_from_page(struct page *page, bool rsvd)
@ -102,9 +131,9 @@ extern void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
struct hugetlb_cgroup *h_cg);
extern void hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages,
struct hugetlb_cgroup *h_cg);
extern void hugetlb_cgroup_uncharge_counter(struct page_counter *p,
unsigned long nr_pages,
struct cgroup_subsys_state *css);
extern void hugetlb_cgroup_uncharge_counter(struct resv_map *resv,
unsigned long start,
unsigned long end);
extern void hugetlb_cgroup_file_init(void) __init;
extern void hugetlb_cgroup_migrate(struct page *oldhpage,
@ -193,6 +222,12 @@ hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages,
{
}
static inline void hugetlb_cgroup_uncharge_counter(struct resv_map *resv,
unsigned long start,
unsigned long end)
{
}
static inline void hugetlb_cgroup_file_init(void)
{
}

47
mm/hugetlb.c
View File

@ -650,6 +650,25 @@ static void set_vma_private_data(struct vm_area_struct *vma,
vma->vm_private_data = (void *)value;
}
static void
resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
struct hugetlb_cgroup *h_cg,
struct hstate *h)
{
#ifdef CONFIG_CGROUP_HUGETLB
if (!h_cg || !h) {
resv_map->reservation_counter = NULL;
resv_map->pages_per_hpage = 0;
resv_map->css = NULL;
} else {
resv_map->reservation_counter =
&h_cg->rsvd_hugepage[hstate_index(h)];
resv_map->pages_per_hpage = pages_per_huge_page(h);
resv_map->css = &h_cg->css;
}
#endif
}
struct resv_map *resv_map_alloc(void)
{
struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
@ -666,6 +685,13 @@ struct resv_map *resv_map_alloc(void)
INIT_LIST_HEAD(&resv_map->regions);
resv_map->adds_in_progress = 0;
/*
* Initialize these to 0. On shared mappings, 0's here indicate these
* fields don't do cgroup accounting. On private mappings, these will be
* re-initialized to the proper values, to indicate that hugetlb cgroup
* reservations are to be un-charged from here.
*/
resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
INIT_LIST_HEAD(&resv_map->region_cache);
list_add(&rg->link, &resv_map->region_cache);
@ -3296,9 +3322,7 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
end = vma_hugecache_offset(h, vma, vma->vm_end);
reserve = (end - start) - region_count(resv, start, end);
kref_put(&resv->refs, resv_map_release);
hugetlb_cgroup_uncharge_counter(resv, start, end);
if (reserve) {
/*
* Decrement reserve counts. The global reserve count may be
@ -3307,6 +3331,8 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
hugetlb_acct_memory(h, -gbl_reserve);
}
kref_put(&resv->refs, resv_map_release);
}
static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
@ -4691,6 +4717,7 @@ int hugetlb_reserve_pages(struct inode *inode,
struct hstate *h = hstate_inode(inode);
struct hugepage_subpool *spool = subpool_inode(inode);
struct resv_map *resv_map;
struct hugetlb_cgroup *h_cg;
long gbl_reserve;
/* This should never happen */
@ -4724,12 +4751,26 @@ int hugetlb_reserve_pages(struct inode *inode,
chg = region_chg(resv_map, from, to);
} else {
/* Private mapping. */
resv_map = resv_map_alloc();
if (!resv_map)
return -ENOMEM;
chg = to - from;
if (hugetlb_cgroup_charge_cgroup_rsvd(
hstate_index(h), chg * pages_per_huge_page(h),
&h_cg)) {
kref_put(&resv_map->refs, resv_map_release);
return -ENOMEM;
}
/*
* Since this branch handles private mappings, we attach the
* counter to uncharge for this reservation off resv_map.
*/
resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
set_vma_resv_map(vma, resv_map);
set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
}

41
mm/hugetlb_cgroup.c
View File

@ -23,34 +23,6 @@
#include <linux/hugetlb.h>
#include <linux/hugetlb_cgroup.h>
enum hugetlb_memory_event {
HUGETLB_MAX,
HUGETLB_NR_MEMORY_EVENTS,
};
struct hugetlb_cgroup {
struct cgroup_subsys_state css;
/*
* the counter to account for hugepages from hugetlb.
*/
struct page_counter hugepage[HUGE_MAX_HSTATE];
/*
* the counter to account for hugepage reservations from hugetlb.
*/
struct page_counter rsvd_hugepage[HUGE_MAX_HSTATE];
atomic_long_t events[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS];
atomic_long_t events_local[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS];
/* Handle for "hugetlb.events" */
struct cgroup_file events_file[HUGE_MAX_HSTATE];
/* Handle for "hugetlb.events.local" */
struct cgroup_file events_local_file[HUGE_MAX_HSTATE];
};
#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
#define MEMFILE_IDX(val) (((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val) ((val) & 0xffff)
@ -407,15 +379,16 @@ void hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages,
__hugetlb_cgroup_uncharge_cgroup(idx, nr_pages, h_cg, true);
}
void hugetlb_cgroup_uncharge_counter(struct page_counter *p,
unsigned long nr_pages,
struct cgroup_subsys_state *css)
void hugetlb_cgroup_uncharge_counter(struct resv_map *resv, unsigned long start,
unsigned long end)
{
if (hugetlb_cgroup_disabled() || !p || !css)
if (hugetlb_cgroup_disabled() || !resv || !resv->reservation_counter ||
!resv->css)
return;
page_counter_uncharge(p, nr_pages);
css_put(css);
page_counter_uncharge(resv->reservation_counter,
(end - start) * resv->pages_per_hpage);
css_put(resv->css);
}
enum {