From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kernel-team@lge.com, Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
Minchan Kim <minchan@kernel.org>
Subject: [PATCH v2 06/10] mm: remove SWAP_AGAIN in ttu
Date: Wed, 15 Mar 2017 14:24:49 +0900 [thread overview]
Message-ID: <1489555493-14659-7-git-send-email-minchan@kernel.org> (raw)
In-Reply-To: <1489555493-14659-1-git-send-email-minchan@kernel.org>
In 2002, [1] introduced SWAP_AGAIN.
At that time, try_to_unmap_one used spin_trylock(&mm->page_table_lock)
so it's really easy to contend and fail to hold a lock so SWAP_AGAIN
to keep LRU status makes sense.
However, now we changed it to mutex-based lock and be able to block
without skip pte so there is few of small window to return SWAP_AGAIN
so remove SWAP_AGAIN and just return SWAP_FAIL.
[1] c48c43e, minimal rmap
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/rmap.c | 11 +++--------
mm/vmscan.c | 2 --
2 files changed, 3 insertions(+), 10 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index a5af1e1..612682c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1499,13 +1499,10 @@ static int page_mapcount_is_zero(struct page *page)
* Return values are:
*
* SWAP_SUCCESS - we succeeded in removing all mappings
- * SWAP_AGAIN - we missed a mapping, try again later
* SWAP_FAIL - the page is unswappable
*/
int try_to_unmap(struct page *page, enum ttu_flags flags)
{
- int ret;
-
struct rmap_walk_control rwc = {
.rmap_one = try_to_unmap_one,
.arg = (void *)flags,
@@ -1525,13 +1522,11 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
rwc.invalid_vma = invalid_migration_vma;
if (flags & TTU_RMAP_LOCKED)
- ret = rmap_walk_locked(page, &rwc);
+ rmap_walk_locked(page, &rwc);
else
- ret = rmap_walk(page, &rwc);
+ rmap_walk(page, &rwc);
- if (!page_mapcount(page))
- ret = SWAP_SUCCESS;
- return ret;
+ return !page_mapcount(page) ? SWAP_SUCCESS : SWAP_FAIL;
}
static int page_not_mapped(struct page *page)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2a208f0..7727fbe 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1145,8 +1145,6 @@ static unsigned long shrink_page_list(struct list_head *page_list,
case SWAP_FAIL:
nr_unmap_fail++;
goto activate_locked;
- case SWAP_AGAIN:
- goto keep_locked;
case SWAP_SUCCESS:
; /* try to free the page below */
}
--
2.7.4
--
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next prev parent reply other threads:[~2017-03-15 5:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 5:24 [PATCH v2 00/10] make try_to_unmap simple Minchan Kim
2017-03-15 5:24 ` [PATCH v2 01/10] mm: remove unncessary ret in page_referenced Minchan Kim
2017-03-15 5:24 ` [PATCH v2 02/10] mm: remove SWAP_DIRTY in ttu Minchan Kim
2017-03-15 5:24 ` [PATCH v2 03/10] mm: remove SWAP_MLOCK check for SWAP_SUCCESS " Minchan Kim
2017-03-15 5:24 ` [PATCH v2 04/10] mm: make the try_to_munlock void function Minchan Kim
2017-03-15 7:31 ` Vlastimil Babka
2017-04-08 3:18 ` alexander.levin
2017-04-11 2:56 ` Minchan Kim
2017-03-15 5:24 ` [PATCH v2 05/10] mm: remove SWAP_MLOCK in ttu Minchan Kim
2017-03-15 5:24 ` Minchan Kim [this message]
2017-03-15 5:24 ` [PATCH v2 07/10] mm: make ttu's return boolean Minchan Kim
2017-03-15 5:24 ` [PATCH v2 08/10] mm: make rmap_walk void function Minchan Kim
2017-03-15 5:24 ` [PATCH v2 09/10] mm: make rmap_one boolean function Minchan Kim
2017-03-15 5:24 ` [PATCH v2 10/10] mm: remove SWAP_[SUCCESS|AGAIN|FAIL] Minchan Kim
2017-03-16 4:40 ` Sergey Senozhatsky
2017-03-16 5:33 ` Minchan Kim
2017-03-16 5:44 ` Sergey Senozhatsky
2017-03-16 5:51 ` Minchan Kim
2017-03-16 5:57 ` Sergey Senozhatsky
2017-03-16 18:54 ` kbuild test robot
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