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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>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Michal Hocko <mhocko@kernel.org>,
	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>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
	Zi Yan <zi.yan@cs.rutgers.edu>,
	Daniel Jordan <daniel.m.jordan@oracle.com>
Subject: [PATCH -V5 RESEND 02/21] swap: Add __swap_duplicate_locked()
Date: Wed, 12 Sep 2018 08:43:55 +0800	[thread overview]
Message-ID: <20180912004414.22583-3-ying.huang@intel.com> (raw)
In-Reply-To: <20180912004414.22583-1-ying.huang@intel.com>

The part of __swap_duplicate() with lock held is separated into a new
function __swap_duplicate_locked().  Because we will add more logic
about the PMD swap mapping into __swap_duplicate() and keep the most
PTE swap mapping related logic in __swap_duplicate_locked().

Just mechanical code refactoring, there is no any functional change in
this patch.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
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: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
---
 mm/swapfile.c | 63 +++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 35 insertions(+), 28 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 97a1bd1a7c9a..6a570ef00fa7 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3436,32 +3436,12 @@ void si_swapinfo(struct sysinfo *val)
 	spin_unlock(&swap_lock);
 }
 
-/*
- * Verify that a swap entry is valid and increment its swap map count.
- *
- * Returns error code in following case.
- * - success -> 0
- * - swp_entry is invalid -> EINVAL
- * - swp_entry is migration entry -> EINVAL
- * - swap-cache reference is requested but there is already one. -> EEXIST
- * - swap-cache reference is requested but the entry is not used. -> ENOENT
- * - swap-mapped reference requested but needs continued swap count. -> ENOMEM
- */
-static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
+static int __swap_duplicate_locked(struct swap_info_struct *p,
+				   unsigned long offset, unsigned char usage)
 {
-	struct swap_info_struct *p;
-	struct swap_cluster_info *ci;
-	unsigned long offset;
 	unsigned char count;
 	unsigned char has_cache;
-	int err = -EINVAL;
-
-	p = get_swap_device(entry);
-	if (!p)
-		goto out;
-
-	offset = swp_offset(entry);
-	ci = lock_cluster_or_swap_info(p, offset);
+	int err = 0;
 
 	count = p->swap_map[offset];
 
@@ -3471,12 +3451,11 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
 	 */
 	if (unlikely(swap_count(count) == SWAP_MAP_BAD)) {
 		err = -ENOENT;
-		goto unlock_out;
+		goto out;
 	}
 
 	has_cache = count & SWAP_HAS_CACHE;
 	count &= ~SWAP_HAS_CACHE;
-	err = 0;
 
 	if (usage == SWAP_HAS_CACHE) {
 
@@ -3503,11 +3482,39 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
 
 	p->swap_map[offset] = count | has_cache;
 
-unlock_out:
+out:
+	return err;
+}
+
+/*
+ * Verify that a swap entry is valid and increment its swap map count.
+ *
+ * Returns error code in following case.
+ * - success -> 0
+ * - swp_entry is invalid -> EINVAL
+ * - swp_entry is migration entry -> EINVAL
+ * - swap-cache reference is requested but there is already one. -> EEXIST
+ * - swap-cache reference is requested but the entry is not used. -> ENOENT
+ * - swap-mapped reference requested but needs continued swap count. -> ENOMEM
+ */
+static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
+{
+	struct swap_info_struct *p;
+	struct swap_cluster_info *ci;
+	unsigned long offset;
+	int err = -EINVAL;
+
+	p = get_swap_device(entry);
+	if (!p)
+		goto out;
+
+	offset = swp_offset(entry);
+	ci = lock_cluster_or_swap_info(p, offset);
+	err = __swap_duplicate_locked(p, offset, usage);
 	unlock_cluster_or_swap_info(p, ci);
+
+	put_swap_device(p);
 out:
-	if (p)
-		put_swap_device(p);
 	return err;
 }
 
-- 
2.16.4


  parent reply	other threads:[~2018-09-12  0:44 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-12  0:43 [PATCH -V5 RESEND 00/21] swap: Swapout/swapin THP in one piece Huang Ying
2018-09-12  0:43 ` [PATCH -V5 RESEND 01/21] swap: Enable PMD swap operations for CONFIG_THP_SWAP Huang Ying
2018-09-12  0:43 ` Huang Ying [this message]
2018-09-12  0:43 ` [PATCH -V5 RESEND 03/21] swap: Support PMD swap mapping in swap_duplicate() Huang Ying
2018-09-12  0:43 ` [PATCH -V5 RESEND 04/21] swap: Support PMD swap mapping in put_swap_page() Huang Ying
2018-09-12  0:43 ` [PATCH -V5 RESEND 05/21] swap: Support PMD swap mapping in free_swap_and_cache()/swap_free() Huang Ying
2018-09-12  0:43 ` [PATCH -V5 RESEND 06/21] swap: Support PMD swap mapping when splitting huge PMD Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 07/21] swap: Support PMD swap mapping in split_swap_cluster() Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 08/21] swap: Support to read a huge swap cluster for swapin a THP Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 09/21] swap: Swapin a THP in one piece Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 10/21] swap: Support to count THP swapin and its fallback Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 11/21] swap: Add sysfs interface to configure THP swapin Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 12/21] swap: Support PMD swap mapping in swapoff Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 13/21] swap: Support PMD swap mapping in madvise_free() Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 14/21] swap: Support to move swap account for PMD swap mapping Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 15/21] swap: Support to copy PMD swap mapping when fork() Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 16/21] swap: Free PMD swap mapping when zap_huge_pmd() Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 17/21] swap: Support PMD swap mapping for MADV_WILLNEED Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 18/21] swap: Support PMD swap mapping in mincore() Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 19/21] swap: Support PMD swap mapping in common path Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 20/21] swap: create PMD swap mapping when unmap the THP Huang Ying
2018-09-12  0:44 ` [PATCH -V5 RESEND 21/21] swap: Update help of CONFIG_THP_SWAP Huang Ying
2018-09-25  7:13 [PATCH -V5 RESEND 00/21] swap: Swapout/swapin THP in one piece Huang Ying
2018-09-25  7:13 ` [PATCH -V5 RESEND 02/21] swap: Add __swap_duplicate_locked() Huang Ying

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