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hugetlbfs: accept subpool min_size mount option and setup accordingly
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Make 'min_size=<value>' be an option when mounting a hugetlbfs.  This
option takes the same value as the 'size' option.  min_size can be
specified without specifying size.  If both are specified, min_size must
be less that or equal to size else the mount will fail.  If min_size is
specified, then at mount time an attempt is made to reserve min_size
pages.  If the reservation fails, the mount fails.  At umount time, the
reserved pages are released.

Signed-off-by: Mike Kravetz <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Aneesh Kumar <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@mjkravetz @torvalds
mjkravetz authored and torvalds committed Apr 15, 2015
1 parent 1c5ecae commit 7ca02d0
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Showing 3 changed files with 94 additions and 24 deletions.
90 changes: 71 additions & 19 deletions fs/hugetlbfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,9 +47,10 @@ struct hugetlbfs_config {
kuid_t uid;
kgid_t gid;
umode_t mode;
long nr_blocks;
long max_hpages;
long nr_inodes;
struct hstate *hstate;
long min_hpages;
};

struct hugetlbfs_inode_info {
Expand All @@ -67,7 +68,7 @@ int sysctl_hugetlb_shm_group;
enum {
Opt_size, Opt_nr_inodes,
Opt_mode, Opt_uid, Opt_gid,
Opt_pagesize,
Opt_pagesize, Opt_min_size,
Opt_err,
};

Expand All @@ -78,6 +79,7 @@ static const match_table_t tokens = {
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_pagesize, "pagesize=%s"},
{Opt_min_size, "min_size=%s"},
{Opt_err, NULL},
};

Expand Down Expand Up @@ -754,14 +756,38 @@ static const struct super_operations hugetlbfs_ops = {
.show_options = generic_show_options,
};

enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };

/*
* Convert size option passed from command line to number of huge pages
* in the pool specified by hstate. Size option could be in bytes
* (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
*/
static long long
hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
int val_type)
{
if (val_type == NO_SIZE)
return -1;

if (val_type == SIZE_PERCENT) {
size_opt <<= huge_page_shift(h);
size_opt *= h->max_huge_pages;
do_div(size_opt, 100);
}

size_opt >>= huge_page_shift(h);
return size_opt;
}

static int
hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
{
char *p, *rest;
substring_t args[MAX_OPT_ARGS];
int option;
unsigned long long size = 0;
enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
unsigned long long max_size_opt = 0, min_size_opt = 0;
int max_val_type = NO_SIZE, min_val_type = NO_SIZE;

if (!options)
return 0;
Expand Down Expand Up @@ -799,10 +825,10 @@ hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(*args[0].from))
goto bad_val;
size = memparse(args[0].from, &rest);
setsize = SIZE_STD;
max_size_opt = memparse(args[0].from, &rest);
max_val_type = SIZE_STD;
if (*rest == '%')
setsize = SIZE_PERCENT;
max_val_type = SIZE_PERCENT;
break;
}

Expand All @@ -825,22 +851,40 @@ hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
break;
}

case Opt_min_size: {
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(*args[0].from))
goto bad_val;
min_size_opt = memparse(args[0].from, &rest);
min_val_type = SIZE_STD;
if (*rest == '%')
min_val_type = SIZE_PERCENT;
break;
}

default:
pr_err("Bad mount option: \"%s\"\n", p);
return -EINVAL;
break;
}
}

/* Do size after hstate is set up */
if (setsize > NO_SIZE) {
struct hstate *h = pconfig->hstate;
if (setsize == SIZE_PERCENT) {
size <<= huge_page_shift(h);
size *= h->max_huge_pages;
do_div(size, 100);
}
pconfig->nr_blocks = (size >> huge_page_shift(h));
/*
* Use huge page pool size (in hstate) to convert the size
* options to number of huge pages. If NO_SIZE, -1 is returned.
*/
pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
max_size_opt, max_val_type);
pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
min_size_opt, min_val_type);

/*
* If max_size was specified, then min_size must be smaller
*/
if (max_val_type > NO_SIZE &&
pconfig->min_hpages > pconfig->max_hpages) {
pr_err("minimum size can not be greater than maximum size\n");
return -EINVAL;
}

return 0;
Expand All @@ -859,12 +903,13 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)

save_mount_options(sb, data);

config.nr_blocks = -1; /* No limit on size by default */
config.max_hpages = -1; /* No limit on size by default */
config.nr_inodes = -1; /* No limit on number of inodes by default */
config.uid = current_fsuid();
config.gid = current_fsgid();
config.mode = 0755;
config.hstate = &default_hstate;
config.min_hpages = -1; /* No default minimum size */
ret = hugetlbfs_parse_options(data, &config);
if (ret)
return ret;
Expand All @@ -878,8 +923,15 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
sbinfo->max_inodes = config.nr_inodes;
sbinfo->free_inodes = config.nr_inodes;
sbinfo->spool = NULL;
if (config.nr_blocks != -1) {
sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
/*
* Allocate and initialize subpool if maximum or minimum size is
* specified. Any needed reservations (for minimim size) are taken
* taken when the subpool is created.
*/
if (config.max_hpages != -1 || config.min_hpages != -1) {
sbinfo->spool = hugepage_new_subpool(config.hstate,
config.max_hpages,
config.min_hpages);
if (!sbinfo->spool)
goto out_free;
}
Expand Down
3 changes: 2 additions & 1 deletion include/linux/hugetlb.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,8 @@ extern int hugetlb_max_hstate __read_mostly;
#define for_each_hstate(h) \
for ((h) = hstates; (h) < &hstates[hugetlb_max_hstate]; (h)++)

struct hugepage_subpool *hugepage_new_subpool(long nr_blocks);
struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
long min_hpages);
void hugepage_put_subpool(struct hugepage_subpool *spool);

void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
Expand Down
25 changes: 21 additions & 4 deletions mm/hugetlb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,19 +61,28 @@ DEFINE_SPINLOCK(hugetlb_lock);
static int num_fault_mutexes;
static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp;

/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
{
bool free = (spool->count == 0) && (spool->used_hpages == 0);

spin_unlock(&spool->lock);

/* If no pages are used, and no other handles to the subpool
* remain, free the subpool the subpool remain */
if (free)
* remain, give up any reservations mased on minimum size and
* free the subpool */
if (free) {
if (spool->min_hpages != -1)
hugetlb_acct_memory(spool->hstate,
-spool->min_hpages);
kfree(spool);
}
}

struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
long min_hpages)
{
struct hugepage_subpool *spool;

Expand All @@ -83,7 +92,15 @@ struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)

spin_lock_init(&spool->lock);
spool->count = 1;
spool->max_hpages = nr_blocks;
spool->max_hpages = max_hpages;
spool->hstate = h;
spool->min_hpages = min_hpages;

if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
kfree(spool);
return NULL;
}
spool->rsv_hpages = min_hpages;

return spool;
}
Expand Down

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