From: Huang Ying <ying.huang@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Huang Ying <ying.huang@intel.com>, Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shaohua Li <shli@kernel.org>, Hugh Dickins <hughd@google.com>,
Minchan Kim <minchan@kernel.org>, Rik van Riel <riel@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: [PATCH v4 3/8] swap: Use swap_count() in swap_page_trans_huge_swapped()
Date: Fri, 20 Jul 2018 15:18:40 +0800 [thread overview]
Message-ID: <20180720071845.17920-4-ying.huang@intel.com> (raw)
In-Reply-To: <20180720071845.17920-1-ying.huang@intel.com>
In swap_page_trans_huge_swapped(), to identify whether there's any
page table mapping for a 4k sized swap entry, "si->swap_map[i] !=
SWAP_HAS_CACHE" is used. This works correctly now, because all users
of the function will only call it after checking SWAP_HAS_CACHE. But
as pointed out by Daniel, it is better to use "swap_count(map[i])"
here, because it works for "map[i] == 0" case too.
And this makes the implementation more consistent between normal and
huge swap entry.
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-and-reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
---
mm/swapfile.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 7283104bfafa..833613e59ef7 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1497,12 +1497,12 @@ static bool swap_page_trans_huge_swapped(struct swap_info_struct *si,
ci = lock_cluster_or_swap_info(si, offset);
if (!ci || !cluster_is_huge(ci)) {
- if (map[roffset] != SWAP_HAS_CACHE)
+ if (swap_count(map[roffset]))
ret = true;
goto unlock_out;
}
for (i = 0; i < SWAPFILE_CLUSTER; i++) {
- if (map[offset + i] != SWAP_HAS_CACHE) {
+ if (swap_count(map[offset + i])) {
ret = true;
break;
}
--
2.16.4
next prev parent reply other threads:[~2018-07-20 7:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-20 7:18 [PATCH v4 0/8] swap: THP optimizing refactoring Huang Ying
2018-07-20 7:18 ` [PATCH v4 1/8] swap: Add comments to lock_cluster_or_swap_info() Huang Ying
2018-07-20 7:18 ` [PATCH v4 2/8] mm/swapfile.c: Replace some #ifdef with IS_ENABLED() Huang Ying
2018-07-20 7:18 ` Huang Ying [this message]
2018-07-20 7:18 ` [PATCH v4 4/8] swap: Unify normal/huge code path in swap_page_trans_huge_swapped() Huang Ying
2018-07-20 7:18 ` [PATCH v4 5/8] swap: Unify normal/huge code path in put_swap_page() Huang Ying
2018-07-20 7:18 ` [PATCH v4 6/8] swap, get_swap_pages: Use entry_size instead of cluster in parameter Huang Ying
2018-07-20 7:18 ` [PATCH v4 7/8] swap: Add __swap_entry_free_locked() Huang Ying
2018-07-20 7:18 ` [PATCH v4 8/8] swap, put_swap_page: Share more between huge/normal code path Huang Ying
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