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 <mike.kravetz@xxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 90 ++++++++++++++++++++++++++++++++++++++-----------
include/linux/hugetlb.h | 3 +-
mm/hugetlb.c | 25 +++++++++++---
3 files changed, 94 insertions(+), 24 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 5eba47f..38d2bc83e 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -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 {
@@ -73,7 +74,7 @@ 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,
};
@@ -84,6 +85,7 @@ 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},
};
@@ -761,14 +763,38 @@ 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;
@@ -806,10 +832,10 @@ 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;
}
@@ -832,6 +858,17 @@ 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;
@@ -839,15 +876,22 @@ hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
}
}
- /* 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;
@@ -866,12 +910,13 @@ 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;
@@ -885,8 +930,15 @@ 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;
}
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 2ec06a1..d2b41f4 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -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);
int PageHuge(struct page *page);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 28a15c3..84511b6 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -61,6 +61,9 @@ 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);
@@ -68,12 +71,18 @@ static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
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;
@@ -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;
}
--
2.1.0
--
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