Make 'min_size=' be an option when mounting a hugetlbfs. This option takes the same value as the 'size' option. min_size can be specified with 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]> --- fs/hugetlbfs/inode.c | 75 ++++++++++++++++++++++++++++++++++++++----------- include/linux/hugetlb.h | 3 +- mm/hugetlb.c | 26 +++++++++++++---- 3 files changed, 80 insertions(+), 24 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 5eba47f..7a20a1b 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -50,6 +50,7 @@ struct hugetlbfs_config { long nr_blocks; long nr_inodes; struct hstate *hstate; + long min_size; }; 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 +763,32 @@ static const struct super_operations hugetlbfs_ops = { .show_options = generic_show_options, }; +enum { NO_SIZE, SIZE_STD, SIZE_PERCENT }; + +static bool +hugetlbfs_options_setsize(struct hstate *h, long long *size, int setsize) +{ + if (setsize == NO_SIZE) + return false; + + if (setsize == SIZE_PERCENT) { + *size <<= huge_page_shift(h); + *size *= h->max_huge_pages; + do_div(*size, 100); + } + + *size >>= huge_page_shift(h); + return true; +} + 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 = 0, min_size = 0; + int max_setsize = NO_SIZE, min_setsize = NO_SIZE; if (!options) return 0; @@ -806,10 +826,10 @@ 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 = memparse(args[0].from, &rest); + max_setsize = SIZE_STD; if (*rest == '%') - setsize = SIZE_PERCENT; + max_setsize = SIZE_PERCENT; break; } @@ -832,6 +852,17 @@ 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 = memparse(args[0].from, &rest); + min_setsize = SIZE_STD; + if (*rest == '%') + min_setsize = SIZE_PERCENT; + break; + } + default: pr_err("Bad mount option: \"%s\"\n", p); return -EINVAL; @@ -839,15 +870,17 @@ 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)); + /* Calculate number of huge pages based on hstate */ + if (hugetlbfs_options_setsize(pconfig->hstate, &max_size, max_setsize)) + pconfig->nr_blocks = max_size; + if (hugetlbfs_options_setsize(pconfig->hstate, &min_size, min_setsize)) + pconfig->min_size = min_size; + + /* If max_size specified, then min_size must be smaller */ + if (max_setsize > NO_SIZE && min_setsize > NO_SIZE && + pconfig->min_size > pconfig->nr_blocks) { + pr_err("minimum size can not be greater than maximum size\n"); + return -EINVAL; } return 0; @@ -872,6 +905,7 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) config.gid = current_fsgid(); config.mode = 0755; config.hstate = &default_hstate; + config.min_size = 0; /* No default minimum size */ ret = hugetlbfs_parse_options(data, &config); if (ret) return ret; @@ -885,8 +919,15 @@ 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.nr_blocks != -1 || config.min_size != 0) { + sbinfo->spool = hugepage_new_subpool(config.hstate, + config.nr_blocks, + config.min_size); if (!sbinfo->spool) goto out_free; } diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index cfe13fd..6883fca 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -40,7 +40,8 @@ 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 nr_blocks, + long min_size); void hugepage_put_subpool(struct hugepage_subpool *spool); int PageHuge(struct page *page); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ab2ea1e..7d4be33 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) + 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 nr_blocks, + long min_size) { struct hugepage_subpool *spool; @@ -85,9 +94,14 @@ struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) spool->count = 1; spool->max_hpages = nr_blocks; spool->used_hpages = 0; - spool->hstate = NULL; - spool->min_hpages = 0; - spool->rsv_hpages = 0; + spool->hstate = h; + spool->min_hpages = min_size; + + if (min_size && hugetlb_acct_memory(h, min_size)) { + kfree(spool); + return NULL; + } + spool->rsv_hpages = min_size; return spool; } -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
