[RFC] remove unnecessary condition in remove_inode_hugepages

From: zhong jiang
Date: Thu Sep 22 2016 - 21:57:55 EST

At present, we need to call hugetlb_fix_reserve_count when hugetlb_unrserve_pages fails,
and PagePrivate will decide hugetlb reserves counts.

we obtain the page from page cache. and use page both lock_page and mutex_lock.
alloc_huge_page add page to page chace always hold lock page, then bail out clearpageprivate
before unlock page.

but I' m not sure it is right or I miss the points.

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 4ea71eb..010723b 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -462,14 +462,12 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
* the page, note PagePrivate which is used in case
* of error.
- rsv_on_error = !PagePrivate(page);
if (!truncate_op) {
if (unlikely(hugetlb_unreserve_pages(inode,
next, next + 1, 1)))
- hugetlb_fix_reserve_counts(inode,
- rsv_on_error);
+ hugetlb_fix_reserve_counts(inode)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index c26d463..d2e0fc5 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -90,7 +90,7 @@ int dequeue_hwpoisoned_huge_page(struct page *page);
bool isolate_huge_page(struct page *page, struct list_head *list);
void putback_active_hugepage(struct page *page);
void free_huge_page(struct page *page);
-void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve);
+void hugetlb_fix_reserve_counts(struct inode *inode);
extern struct mutex *hugetlb_fault_mutex_table;
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
struct vm_area_struct *vma,
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 87e11d8..28a079a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -567,13 +567,13 @@ retry:
* appear as a "reserved" entry instead of simply dangling with incorrect
* counts.
-void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve)
+void hugetlb_fix_reserve_counts(struct inode *inode)
struct hugepage_subpool *spool = subpool_inode(inode);
long rsv_adjust;

rsv_adjust = hugepage_subpool_get_pages(spool, 1);
- if (restore_reserve && rsv_adjust) {
+ if (rsv_adjust) {
struct hstate *h = hstate_inode(inode);

hugetlb_acct_memory(h, 1);