linux-kernel - [PATCH] PM: hibernate: make compression threads configurable via kernel parameter

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250826091937.991667-1-luoxueqin@kylinos.cn>
Date: Tue, 26 Aug 2025 17:19:37 +0800
From: Xueqin Luo <luoxueqin@...inos.cn>
To: rafael@...nel.org,
	pavel@...nel.org,
	lenb@...nel.org,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Xueqin Luo <luoxueqin@...inos.cn>
Subject: [PATCH] PM: hibernate: make compression threads configurable via kernel parameter

A new kernel parameter 'cmp_threads=' is introduced to
allow tuning the number of compression/decompression threads at boot.

Signed-off-by: Xueqin Luo <luoxueqin@...inos.cn>
---
 kernel/power/swap.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index ad13c461b657..43280e08a4ad 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -520,7 +520,8 @@ static int swap_writer_finish(struct swap_map_handle *handle,
 #define CMP_SIZE	(CMP_PAGES * PAGE_SIZE)
 
 /* Maximum number of threads for compression/decompression. */
-#define CMP_THREADS	3
+#define CMP_MAX_THREADS	12
+static int cmp_threads = 3
 
 /* Minimum/maximum number of pages for read buffering. */
 #define CMP_MIN_RD_PAGES	1024
@@ -585,8 +586,8 @@ struct crc_data {
 	wait_queue_head_t go;                     /* start crc update */
 	wait_queue_head_t done;                   /* crc update done */
 	u32 *crc32;                               /* points to handle's crc32 */
-	size_t *unc_len[CMP_THREADS];             /* uncompressed lengths */
-	unsigned char *unc[CMP_THREADS];          /* uncompressed data */
+	size_t *unc_len[CMP_MAX_THREADS];             /* uncompressed lengths */
+	unsigned char *unc[CMP_MAX_THREADS];          /* uncompressed data */
 };
 
 /*
@@ -703,7 +704,7 @@ static int save_compressed_image(struct swap_map_handle *handle,
 	 * footprint.
 	 */
 	nr_threads = num_online_cpus() - 1;
-	nr_threads = clamp_val(nr_threads, 1, CMP_THREADS);
+	nr_threads = clamp_val(nr_threads, 1, cmp_threads);
 
 	page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
 	if (!page) {
@@ -1223,7 +1224,7 @@ static int load_compressed_image(struct swap_map_handle *handle,
 	 * footprint.
 	 */
 	nr_threads = num_online_cpus() - 1;
-	nr_threads = clamp_val(nr_threads, 1, CMP_THREADS);
+	nr_threads = clamp_val(nr_threads, 1, cmp_threads);
 
 	page = vmalloc(array_size(CMP_MAX_RD_PAGES, sizeof(*page)));
 	if (!page) {
@@ -1667,3 +1668,14 @@ static int __init swsusp_header_init(void)
 }
 
 core_initcall(swsusp_header_init);
+
+static int __init cmp_threads_setup(char *str)
+{
+       int rc = kstrtouint(str, 0, &cmp_threads);
+       if (rc)
+               return rc;
+       return 1;
+
+}
+
+__setup("cmp_threads=", cmp_threads_setup);
-- 
2.43.0