* [PATCH v3] mm: remove unnecessary condition in remove_inode_hugepages
@ 2016-09-29 1:42 zhongjiang
2016-09-29 8:27 ` Michal Hocko
0 siblings, 1 reply; 2+ messages in thread
From: zhongjiang @ 2016-09-29 1:42 UTC (permalink / raw)
To: akpm; +Cc: mike.kravetz, n-horiguchi, mhocko, linux-mm
From: zhong jiang <zhongjiang@huawei.com>
when the huge page is added to the page cahce (huge_add_to_page_cache),
the page private flag will be cleared. since this code
(remove_inode_hugepages) will only be called for pages in the
page cahce, PagePrivate(page) will always be false.
The patch remove the code without any functional change.
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
---
fs/hugetlbfs/inode.c | 12 +++++-------
include/linux/hugetlb.h | 2 +-
mm/hugetlb.c | 4 ++--
3 files changed, 8 insertions(+), 10 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 4ea71eb..7337cac 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -416,7 +416,6 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
for (i = 0; i < pagevec_count(&pvec); ++i) {
struct page *page = pvec.pages[i];
- bool rsv_on_error;
u32 hash;
/*
@@ -458,18 +457,17 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
* cache (remove_huge_page) BEFORE removing the
* region/reserve map (hugetlb_unreserve_pages). In
* rare out of memory conditions, removal of the
- * region/reserve map could fail. Before free'ing
- * the page, note PagePrivate which is used in case
- * of error.
+ * region/reserve map could fail. Correspondingly,
+ * the subpool and global reserve usage count can need
+ * to be adjusted.
*/
- rsv_on_error = !PagePrivate(page);
+ VM_BUG_ON(PagePrivate(page));
remove_huge_page(page);
freed++;
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);
}
unlock_page(page);
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);
--
1.8.3.1
--
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v3] mm: remove unnecessary condition in remove_inode_hugepages
2016-09-29 1:42 [PATCH v3] mm: remove unnecessary condition in remove_inode_hugepages zhongjiang
@ 2016-09-29 8:27 ` Michal Hocko
0 siblings, 0 replies; 2+ messages in thread
From: Michal Hocko @ 2016-09-29 8:27 UTC (permalink / raw)
To: zhongjiang; +Cc: akpm, mike.kravetz, n-horiguchi, linux-mm
On Thu 29-09-16 09:42:03, zhongjiang wrote:
> From: zhong jiang <zhongjiang@huawei.com>
>
> when the huge page is added to the page cahce (huge_add_to_page_cache),
> the page private flag will be cleared. since this code
> (remove_inode_hugepages) will only be called for pages in the
> page cahce, PagePrivate(page) will always be false.
>
> The patch remove the code without any functional change.
>
> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
> Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
> Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> fs/hugetlbfs/inode.c | 12 +++++-------
> include/linux/hugetlb.h | 2 +-
> mm/hugetlb.c | 4 ++--
> 3 files changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 4ea71eb..7337cac 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -416,7 +416,6 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
>
> for (i = 0; i < pagevec_count(&pvec); ++i) {
> struct page *page = pvec.pages[i];
> - bool rsv_on_error;
> u32 hash;
>
> /*
> @@ -458,18 +457,17 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
> * cache (remove_huge_page) BEFORE removing the
> * region/reserve map (hugetlb_unreserve_pages). In
> * rare out of memory conditions, removal of the
> - * region/reserve map could fail. Before free'ing
> - * the page, note PagePrivate which is used in case
> - * of error.
> + * region/reserve map could fail. Correspondingly,
> + * the subpool and global reserve usage count can need
> + * to be adjusted.
> */
> - rsv_on_error = !PagePrivate(page);
> + VM_BUG_ON(PagePrivate(page));
> remove_huge_page(page);
> freed++;
> 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);
> }
>
> unlock_page(page);
> 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);
> --
> 1.8.3.1
--
Michal Hocko
SUSE Labs
--
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