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authorMike Kravetz <mike.kravetz@oracle.com>2023-10-19 05:31:06 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-10-26 02:47:07 +0300
commitcfb8c75099dbf152db1b075eead5029c5a30ce51 (patch)
treedcce91e1071ed741f26166bbf0c1aebc1acb2910 /mm/hugetlb.c
parent79359d6d24df2f304abbf6f137b01d2b76175ce3 (diff)
downloadlinux-cfb8c75099dbf152db1b075eead5029c5a30ce51.tar.xz
hugetlb: perform vmemmap restoration on a list of pages
The routine update_and_free_pages_bulk already performs vmemmap restoration on the list of hugetlb pages in a separate step. In preparation for more functionality to be added in this step, create a new routine hugetlb_vmemmap_restore_folios() that will restore vmemmap for a list of folios. This new routine must provide sufficient feedback about errors and actual restoration performed so that update_and_free_pages_bulk can perform optimally. Special care must be taken when encountering an error from hugetlb_vmemmap_restore_folios. We want to continue making as much forward progress as possible. A new routine bulk_vmemmap_restore_error handles this specific situation. Link: https://lkml.kernel.org/r/20231019023113.345257-5-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Barry Song <21cnbao@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: James Houghton <jthoughton@google.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Konrad Dybcio <konradybcio@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Usama Arif <usama.arif@bytedance.com> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c99
1 files changed, 71 insertions, 28 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 8b171f866d0a..cf834bb7f820 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1859,50 +1859,93 @@ static void update_and_free_hugetlb_folio(struct hstate *h, struct folio *folio,
schedule_work(&free_hpage_work);
}
-static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list)
+static void bulk_vmemmap_restore_error(struct hstate *h,
+ struct list_head *folio_list,
+ struct list_head *non_hvo_folios)
{
struct folio *folio, *t_folio;
- bool clear_dtor = false;
- /*
- * First allocate required vmemmmap (if necessary) for all folios on
- * list. If vmemmap can not be allocated, we can not free folio to
- * lower level allocator, so add back as hugetlb surplus page.
- * add_hugetlb_folio() removes the page from THIS list.
- * Use clear_dtor to note if vmemmap was successfully allocated for
- * ANY page on the list.
- */
- list_for_each_entry_safe(folio, t_folio, list, lru) {
- if (folio_test_hugetlb_vmemmap_optimized(folio)) {
+ if (!list_empty(non_hvo_folios)) {
+ /*
+ * Free any restored hugetlb pages so that restore of the
+ * entire list can be retried.
+ * The idea is that in the common case of ENOMEM errors freeing
+ * hugetlb pages with vmemmap we will free up memory so that we
+ * can allocate vmemmap for more hugetlb pages.
+ */
+ list_for_each_entry_safe(folio, t_folio, non_hvo_folios, lru) {
+ list_del(&folio->lru);
+ spin_lock_irq(&hugetlb_lock);
+ __clear_hugetlb_destructor(h, folio);
+ spin_unlock_irq(&hugetlb_lock);
+ update_and_free_hugetlb_folio(h, folio, false);
+ cond_resched();
+ }
+ } else {
+ /*
+ * In the case where there are no folios which can be
+ * immediately freed, we loop through the list trying to restore
+ * vmemmap individually in the hope that someone elsewhere may
+ * have done something to cause success (such as freeing some
+ * memory). If unable to restore a hugetlb page, the hugetlb
+ * page is made a surplus page and removed from the list.
+ * If are able to restore vmemmap and free one hugetlb page, we
+ * quit processing the list to retry the bulk operation.
+ */
+ list_for_each_entry_safe(folio, t_folio, folio_list, lru)
if (hugetlb_vmemmap_restore(h, &folio->page)) {
+ list_del(&folio->lru);
spin_lock_irq(&hugetlb_lock);
add_hugetlb_folio(h, folio, true);
spin_unlock_irq(&hugetlb_lock);
- } else
- clear_dtor = true;
- }
+ } else {
+ list_del(&folio->lru);
+ spin_lock_irq(&hugetlb_lock);
+ __clear_hugetlb_destructor(h, folio);
+ spin_unlock_irq(&hugetlb_lock);
+ update_and_free_hugetlb_folio(h, folio, false);
+ cond_resched();
+ break;
+ }
}
+}
+
+static void update_and_free_pages_bulk(struct hstate *h,
+ struct list_head *folio_list)
+{
+ long ret;
+ struct folio *folio, *t_folio;
+ LIST_HEAD(non_hvo_folios);
/*
- * If vmemmmap allocation was performed on any folio above, take lock
- * to clear destructor of all folios on list. This avoids the need to
- * lock/unlock for each individual folio.
- * The assumption is vmemmap allocation was performed on all or none
- * of the folios on the list. This is true expect in VERY rare cases.
+ * First allocate required vmemmmap (if necessary) for all folios.
+ * Carefully handle errors and free up any available hugetlb pages
+ * in an effort to make forward progress.
*/
- if (clear_dtor) {
+retry:
+ ret = hugetlb_vmemmap_restore_folios(h, folio_list, &non_hvo_folios);
+ if (ret < 0) {
+ bulk_vmemmap_restore_error(h, folio_list, &non_hvo_folios);
+ goto retry;
+ }
+
+ /*
+ * At this point, list should be empty, ret should be >= 0 and there
+ * should only be pages on the non_hvo_folios list.
+ * Do note that the non_hvo_folios list could be empty.
+ * Without HVO enabled, ret will be 0 and there is no need to call
+ * __clear_hugetlb_destructor as this was done previously.
+ */
+ VM_WARN_ON(!list_empty(folio_list));
+ VM_WARN_ON(ret < 0);
+ if (!list_empty(&non_hvo_folios) && ret) {
spin_lock_irq(&hugetlb_lock);
- list_for_each_entry(folio, list, lru)
+ list_for_each_entry(folio, &non_hvo_folios, lru)
__clear_hugetlb_destructor(h, folio);
spin_unlock_irq(&hugetlb_lock);
}
- /*
- * Free folios back to low level allocators. vmemmap and destructors
- * were taken care of above, so update_and_free_hugetlb_folio will
- * not need to take hugetlb lock.
- */
- list_for_each_entry_safe(folio, t_folio, list, lru) {
+ list_for_each_entry_safe(folio, t_folio, &non_hvo_folios, lru) {
update_and_free_hugetlb_folio(h, folio, false);
cond_resched();
}