On 04/06/2016 12:53 AM, Hugh Dickins wrote:
> +static void shmem_recovery_work(struct work_struct *work)
> +{
> + struct recovery *recovery;
> + struct shmem_inode_info *info;
> + struct address_space *mapping;
> + struct page *page;
> + struct page *head = NULL;
> + int error = -ENOENT;
> +
> + recovery = container_of(work, struct recovery, work);
> + info = SHMEM_I(recovery->inode);
> + if (!shmem_work_still_useful(recovery)) {
> + shr_stats(work_too_late);
> + goto out;
> + }
> +
> + /* Are we resuming from an earlier partially successful attempt? */
> + mapping = recovery->inode->i_mapping;
> + spin_lock_irq(&mapping->tree_lock);
> + page = shmem_clear_tag_hugehole(mapping, recovery->head_index);
> + if (page)
> + head = team_head(page);
> + spin_unlock_irq(&mapping->tree_lock);
> + if (head) {
> + /* Serialize with shrinker so it won't mess with our range */
> + spin_lock(&shmem_shrinklist_lock);
> + spin_unlock(&shmem_shrinklist_lock);
> + }
> +
> + /* If team is now complete, no tag and head would be found above */
> + page = recovery->page;
> + if (PageTeam(page))
> + head = team_head(page);
> +
> + /* Get a reference to the head of the team already being assembled */
> + if (head) {
> + if (!get_page_unless_zero(head))
> + head = NULL;
> + else if (!PageTeam(head) || head->mapping != mapping ||
> + head->index != recovery->head_index) {
> + put_page(head);
> + head = NULL;
> + }
> + }
> +
> + if (head) {
> + /* We are resuming work from a previous partial recovery */
> + if (PageTeam(page))
> + shr_stats(resume_teamed);
> + else
> + shr_stats(resume_tagged);
> + } else {
> + gfp_t gfp = mapping_gfp_mask(mapping);
> + /*
> + * XXX: Note that with swapin readahead, page_to_nid(page) will
> + * often choose an unsuitable NUMA node: something to fix soon,
> + * but not an immediate blocker.
> + */
> + head = __alloc_pages_node(page_to_nid(page),
> + gfp | __GFP_NOWARN | __GFP_THISNODE, HPAGE_PMD_ORDER);
> + if (!head) {
> + shr_stats(huge_failed);
> + error = -ENOMEM;
> + goto out;
> + }
Should this head marked PageTeam? Because in patch 27/31 when given as a hint to shmem_getpage_gfp() :
hugehint = NULL;
+ if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+ sgp == SGP_TEAM && *pagep) {
+ struct page *head;
+
+ if (!get_page_unless_zero(*pagep)) {
+ error = -ENOENT;
+ goto decused;
+ }
+ page = *pagep;
+ lock_page(page);
+ head = page - (index & (HPAGE_PMD_NR-1));
we fail always because :
+ if (!PageTeam(head)) {
+ error = -ENOENT;
+ goto decused;
+ }
> + if (!shmem_work_still_useful(recovery)) {
> + __free_pages(head, HPAGE_PMD_ORDER);
> + shr_stats(huge_too_late);
> + goto out;
> + }
> + split_page(head, HPAGE_PMD_ORDER);
> + get_page(head);
> + shr_stats(huge_alloced);
> + }
Thanks,
Mika
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