diff options
| -rw-r--r-- | mm/hugetlb.c | 123 |
1 files changed, 100 insertions, 23 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4494976..499cb72 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -96,36 +96,89 @@ void hugepage_put_subpool(struct hugepage_subpool *spool) unlock_or_release_subpool(spool); } -static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, +/* + * Subpool accounting for allocating and reserving pages. + * Return -ENOMEM if there are not enough resources to satisfy the + * the request. Otherwise, return the number of pages by which the + * global pools must be adjusted (upward). The returned value may + * only be different than the passed value (delta) in the case where + * a subpool minimum size must be manitained. + */ +static long hugepage_subpool_get_pages(struct hugepage_subpool *spool, long delta) { - int ret = 0; + long ret = delta; if (!spool) - return 0; + return ret; spin_lock(&spool->lock); - if ((spool->used_hpages + delta) <= spool->max_hpages) { - spool->used_hpages += delta; - } else { - ret = -ENOMEM; + + if (spool->max_hpages != -1) { /* maximum size accounting */ + if ((spool->used_hpages + delta) <= spool->max_hpages) + spool->used_hpages += delta; + else { + ret = -ENOMEM; + goto unlock_ret; + } } - spin_unlock(&spool->lock); + if (spool->min_hpages != -1) { /* minimum size accounting */ + if (delta > spool->rsv_hpages) { + /* + * Asking for more reserves than those already taken on + * behalf of subpool. Return difference. + */ + ret = delta - spool->rsv_hpages; + spool->rsv_hpages = 0; + } else { + ret = 0; /* reserves already accounted for */ + spool->rsv_hpages -= delta; + } + } + +unlock_ret: + spin_unlock(&spool->lock); return ret; } -static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, +/* + * Subpool accounting for freeing and unreserving pages. + * Return the number of global page reservations that must be dropped. + * The return value may only be different than the passed value (delta) + * in the case where a subpool minimum size must be maintained. + */ +static long hugepage_subpool_put_pages(struct hugepage_subpool *spool, long delta) { + long ret = delta; + if (!spool) - return; + return delta; spin_lock(&spool->lock); - spool->used_hpages -= delta; - /* If hugetlbfs_put_super couldn't free spool due to - * an outstanding quota reference, free it now. */ + + if (spool->max_hpages != -1) /* maximum size accounting */ + spool->used_hpages -= delta; + + if (spool->min_hpages != -1) { /* minimum size accounting */ + if (spool->rsv_hpages + delta <= spool->min_hpages) + ret = 0; + else + ret = spool->rsv_hpages + delta - spool->min_hpages; + + spool->rsv_hpages += delta; + if (spool->rsv_hpages > spool->min_hpages) + spool->rsv_hpages = spool->min_hpages; + } + + /* + * If hugetlbfs_put_super couldn't free spool due to an outstanding + * quota reference, free it now. + */ unlock_or_release_subpool(spool); + + return ret; } static inline struct hugepage_subpool *subpool_inode(struct inode *inode) @@ -873,6 +926,14 @@ void free_huge_page(struct page *page) restore_reserve = PagePrivate(page); ClearPagePrivate(page); + /* + * A return code of zero implies that the subpool will be under its + * minimum size if the reservation is not restored after page is free. + * Therefore, force restore_reserve operation. + */ + if (hugepage_subpool_put_pages(spool, 1) == 0) + restore_reserve = true; + spin_lock(&hugetlb_lock); hugetlb_cgroup_uncharge_page(hstate_index(h), pages_per_huge_page(h), page); @@ -890,7 +951,6 @@ void free_huge_page(struct page *page) enqueue_huge_page(h, page); } spin_unlock(&hugetlb_lock); - hugepage_subpool_put_pages(spool, 1); } static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) @@ -1385,7 +1445,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, if (chg < 0) return ERR_PTR(-ENOMEM); if (chg || avoid_reserve) - if (hugepage_subpool_get_pages(spool, 1)) + if (hugepage_subpool_get_pages(spool, 1) < 0) return ERR_PTR(-ENOSPC); ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); @@ -2453,6 +2513,7 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma) struct resv_map *resv = vma_resv_map(vma); struct hugepage_subpool *spool = subpool_vma(vma); unsigned long reserve, start, end; + long gbl_reserve; if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) return; @@ -2465,8 +2526,12 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma) kref_put(&resv->refs, resv_map_release); if (reserve) { - hugetlb_acct_memory(h, -reserve); - hugepage_subpool_put_pages(spool, reserve); + /* + * Decrement reserve counts. The global reserve count may be + * adjusted if the subpool has a minimum size. + */ + gbl_reserve = hugepage_subpool_put_pages(spool, reserve); + hugetlb_acct_memory(h, -gbl_reserve); } } @@ -3446,6 +3511,7 @@ 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; + long gbl_reserve; /* * Only apply hugepage reservation if asked. At fault time, an @@ -3482,8 +3548,13 @@ int hugetlb_reserve_pages(struct inode *inode, goto out_err; } - /* There must be enough pages in the subpool for the mapping */ - if (hugepage_subpool_get_pages(spool, chg)) { + /* + * There must be enough pages in the subpool for the mapping. If + * the subpool has a minimum size, there may be some global + * reservations already in place (gbl_reserve). + */ + gbl_reserve = hugepage_subpool_get_pages(spool, chg); + if (gbl_reserve < 0) { ret = -ENOSPC; goto out_err; } @@ -3492,9 +3563,10 @@ int hugetlb_reserve_pages(struct inode *inode, * Check enough hugepages are available for the reservation. * Hand the pages back to the subpool if there are not */ - ret = hugetlb_acct_memory(h, chg); + ret = hugetlb_acct_memory(h, gbl_reserve); if (ret < 0) { - hugepage_subpool_put_pages(spool, chg); + /* put back original number of pages, chg */ + (void)hugepage_subpool_put_pages(spool, chg); goto out_err; } @@ -3524,6 +3596,7 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) struct resv_map *resv_map = inode_resv_map(inode); long chg = 0; struct hugepage_subpool *spool = subpool_inode(inode); + long gbl_reserve; if (resv_map) chg = region_truncate(resv_map, offset); @@ -3531,8 +3604,12 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) inode->i_blocks -= (blocks_per_huge_page(h) * freed); spin_unlock(&inode->i_lock); - hugepage_subpool_put_pages(spool, (chg - freed)); - hugetlb_acct_memory(h, -(chg - freed)); + /* + * If the subpool has a minimum size, the number of global + * reservations to be released may be adjusted. + */ + gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed)); + hugetlb_acct_memory(h, -gbl_reserve); } #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE |
