From 0f0746589e4be071a8f890b2035c97c30c7a4e16 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minchan@kernel.org>
Date: Thu, 6 Jul 2017 15:37:24 -0700
Subject: [PATCH] mm, THP, swap: move anonymous THP split logic to vmscan
The add_to_swap aims to allocate swap_space(ie, swap slot and swapcache)
so if it fails due to lack of space in case of THP or something(hdd swap
but tries THP swapout) *caller* rather than add_to_swap itself should
split the THP page and retry it with base page which is more natural.
Link: http://lkml.kernel.org/r/20170515112522.32457-4-ying.huang@intel.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/swap.h | 4 ++--
mm/swap_state.c | 23 ++++++-----------------
mm/vmscan.c | 17 ++++++++++++++++-
3 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index ead6fd7966b4f..5ab1c98c7d274 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -353,7 +353,7 @@ extern struct address_space *swapper_spaces[];
>> SWAP_ADDRESS_SPACE_SHIFT])
extern unsigned long total_swapcache_pages(void);
extern void show_swap_cache_info(void);
-extern int add_to_swap(struct page *, struct list_head *list);
+extern int add_to_swap(struct page *page);
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
extern void __delete_from_swap_cache(struct page *);
@@ -473,7 +473,7 @@ static inline struct page *lookup_swap_cache(swp_entry_t swp)
return NULL;
}
-static inline int add_to_swap(struct page *page, struct list_head *list)
+static inline int add_to_swap(struct page *page)
{
return 0;
}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 0ad214d7a7ad2..9c71b6b2562fe 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -184,7 +184,7 @@ void __delete_from_swap_cache(struct page *page)
* Allocate swap space for the page and add the page to the
* swap cache. Caller needs to hold the page lock.
*/
-int add_to_swap(struct page *page, struct list_head *list)
+int add_to_swap(struct page *page)
{
swp_entry_t entry;
int err;
@@ -192,12 +192,12 @@ int add_to_swap(struct page *page, struct list_head *list)
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(!PageUptodate(page), page);
-retry:
entry = get_swap_page(page);
if (!entry.val)
- goto fail;
+ return 0;
+
if (mem_cgroup_try_charge_swap(page, entry))
- goto fail_free;
+ goto fail;
/*
* Radix-tree node allocations from PF_MEMALLOC contexts could
@@ -218,23 +218,12 @@ int add_to_swap(struct page *page, struct list_head *list)
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
* clear SWAP_HAS_CACHE flag.
*/
- goto fail_free;
-
- if (PageTransHuge(page)) {
- err = split_huge_page_to_list(page, list);
- if (err) {
- delete_from_swap_cache(page);
- return 0;
- }
- }
+ goto fail;
return 1;
-fail_free:
- put_swap_page(page, entry);
fail:
- if (PageTransHuge(page) && !split_huge_page_to_list(page, list))
- goto retry;
+ put_swap_page(page, entry);
return 0;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index cb7c154a4a9dc..729e37f02de67 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1125,8 +1125,23 @@ static unsigned long shrink_page_list(struct list_head *page_list,
!PageSwapCache(page)) {
if (!(sc->gfp_mask & __GFP_IO))
goto keep_locked;
- if (!add_to_swap(page, page_list))
+ if (!add_to_swap(page)) {
+ if (!PageTransHuge(page))
+ goto activate_locked;
+ /* Split THP and swap individual base pages */
+ if (split_huge_page_to_list(page, page_list))
+ goto activate_locked;
+ if (!add_to_swap(page))
+ goto activate_locked;
+ }
+
+ /* XXX: We don't support THP writes */
+ if (PageTransHuge(page) &&
+ split_huge_page_to_list(page, page_list)) {
+ delete_from_swap_cache(page);
goto activate_locked;
+ }
+
may_enter_fs = 1;
/* Adding to swap updated mapping */
--
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