From: Baoquan He <bhe@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, ryncsn@gmail.com,
chrisl@kernel.org, Baoquan He <bhe@redhat.com>
Subject: [PATCH 07/12] mm/swapfile.c: optimize code in setup_clusters()
Date: Wed, 5 Feb 2025 17:27:16 +0800 [thread overview]
Message-ID: <20250205092721.9395-8-bhe@redhat.com> (raw)
In-Reply-To: <20250205092721.9395-1-bhe@redhat.com>
In the last 'for' loop inside setup_clusters(), using two local variable
'k' and 'j' are obvisouly redundant. Using 'j' is enough and simpler.
And also move macro SWAP_CLUSTER_COLS close to its only user
setup_clusters().
Signed-off-by: Baoquan He <bhe@redhat.com>
---
mm/swapfile.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9ee2238042a5..78b7329ad2c7 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3123,13 +3123,6 @@ static unsigned long read_swap_header(struct swap_info_struct *si,
return maxpages;
}
-#define SWAP_CLUSTER_INFO_COLS \
- DIV_ROUND_UP(L1_CACHE_BYTES, sizeof(struct swap_cluster_info))
-#define SWAP_CLUSTER_SPACE_COLS \
- DIV_ROUND_UP(SWAP_ADDRESS_SPACE_PAGES, SWAPFILE_CLUSTER)
-#define SWAP_CLUSTER_COLS \
- max_t(unsigned int, SWAP_CLUSTER_INFO_COLS, SWAP_CLUSTER_SPACE_COLS)
-
static int setup_swap_map_and_extents(struct swap_info_struct *si,
union swap_header *swap_header,
unsigned char *swap_map,
@@ -3169,13 +3162,20 @@ static int setup_swap_map_and_extents(struct swap_info_struct *si,
return nr_extents;
}
+#define SWAP_CLUSTER_INFO_COLS \
+ DIV_ROUND_UP(L1_CACHE_BYTES, sizeof(struct swap_cluster_info))
+#define SWAP_CLUSTER_SPACE_COLS \
+ DIV_ROUND_UP(SWAP_ADDRESS_SPACE_PAGES, SWAPFILE_CLUSTER)
+#define SWAP_CLUSTER_COLS \
+ max_t(unsigned int, SWAP_CLUSTER_INFO_COLS, SWAP_CLUSTER_SPACE_COLS)
+
static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
union swap_header *swap_header,
unsigned long maxpages)
{
unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER);
struct swap_cluster_info *cluster_info;
- unsigned long i, j, k, idx;
+ unsigned long i, j, idx;
int cpu, err = -ENOMEM;
cluster_info = kvcalloc(nr_clusters, sizeof(*cluster_info), GFP_KERNEL);
@@ -3236,8 +3236,7 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
* Reduce false cache line sharing between cluster_info and
* sharing same address space.
*/
- for (k = 0; k < SWAP_CLUSTER_COLS; k++) {
- j = k % SWAP_CLUSTER_COLS;
+ for (j = 0; j < SWAP_CLUSTER_COLS; j++) {
for (i = 0; i < DIV_ROUND_UP(nr_clusters, SWAP_CLUSTER_COLS); i++) {
struct swap_cluster_info *ci;
idx = i * SWAP_CLUSTER_COLS + j;
--
2.41.0
next prev parent reply other threads:[~2025-02-05 9:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-05 9:27 [PATCH 00/12] Tiny cleanup and improvements about SWAP code Baoquan He
2025-02-05 9:27 ` [PATCH 01/12] mm/swap_state.c: fix the obsolete code comment Baoquan He
2025-02-05 9:27 ` [PATCH 02/12] mm/swap_state.c: optimize the code in clear_shadow_from_swap_cache() Baoquan He
2025-02-05 9:27 ` [PATCH 03/12] mm/swap: remove SWAP_FLAG_PRIO_SHIFT Baoquan He
2025-02-05 9:27 ` [PATCH 04/12] mm/swap: skip scanning cluster range if it's empty cluster Baoquan He
2025-02-05 17:07 ` Kairui Song
2025-02-06 1:40 ` Baoquan He
2025-02-06 2:14 ` Kairui Song
2025-02-05 9:27 ` [PATCH 05/12] mm/swap: rename swap_is_has_cache() to swap_only_has_cache() Baoquan He
2025-02-05 9:27 ` [PATCH 06/12] mm/swapfile.c: update the code comment above swap_count_continued() Baoquan He
2025-02-06 7:50 ` Kairui Song
2025-02-07 2:46 ` Baoquan He
2025-02-07 2:50 ` [PATCH v2 " Baoquan He
2025-02-05 9:27 ` Baoquan He [this message]
2025-02-05 9:27 ` [PATCH 08/12] mm/swap_state.c: remove the meaningless code comment Baoquan He
2025-02-05 9:27 ` [PATCH 09/12] mm/swapfile.c: remove the unneeded checking Baoquan He
2025-02-05 9:27 ` [PATCH 10/12] mm/swap: rename swap_swapcount() to swap_entry_swapped() Baoquan He
2025-02-05 9:27 ` [PATCH 11/12] mm/swapfile.c: remove the incorrect code comment Baoquan He
2025-02-05 9:27 ` [PATCH 12/12] mm/swapfile.c: open code cluster_alloc_swap() Baoquan He
2025-02-07 9:36 ` [PATCH 00/12] Tiny cleanup and improvements about SWAP code Kairui Song
2025-02-08 1:08 ` Baoquan He
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250205092721.9395-8-bhe@redhat.com \
--to=bhe@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=chrisl@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ryncsn@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox