From b57100a3d9ced8c2b78e87d313f514a3338d016e Mon Sep 17 00:00:00 2001 From: Malaya Kumar Rout Date: Tue, 14 Oct 2025 01:00:27 +0530 Subject: PM: console: Fix memory allocation error handling in pm_vt_switch_required() The pm_vt_switch_required() function fails silently when memory allocation fails, offering no indication to callers that the operation was unsuccessful. This behavior prevents drivers from handling allocation errors correctly or implementing retry mechanisms. By ensuring that failures are reported back to the caller, drivers can make informed decisions, improve robustness, and avoid unexpected behavior during critical power management operations. Change the function signature to return an integer error code and modify the implementation to return -ENOMEM when kmalloc() fails. Update both the function declaration and the inline stub in include/linux/pm.h to maintain consistency across CONFIG_VT_CONSOLE_SLEEP configurations. The function now returns: - 0 on success (including when updating existing entries) - -ENOMEM when memory allocation fails This change improves error reporting without breaking existing callers, as the current callers in drivers/video/fbdev/core/fbmem.c already ignore the return value, making this a backward-compatible improvement. Reviewed-by: Lyude Paul Signed-off-by: Malaya Kumar Rout Reviewed-by: Dhruva Gole Reviewed-by: Lyude Paul Link: https://patch.msgid.link/20251013193028.89570-1-mrout@redhat.com Signed-off-by: Rafael J. Wysocki --- kernel/power/console.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/console.c b/kernel/power/console.c index 19c48aa5355d..a906a0ac0f9b 100644 --- a/kernel/power/console.c +++ b/kernel/power/console.c @@ -44,9 +44,10 @@ static LIST_HEAD(pm_vt_switch_list); * no_console_suspend argument has been passed on the command line, VT * switches will occur. */ -void pm_vt_switch_required(struct device *dev, bool required) +int pm_vt_switch_required(struct device *dev, bool required) { struct pm_vt_switch *entry, *tmp; + int ret = 0; mutex_lock(&vt_switch_mutex); list_for_each_entry(tmp, &pm_vt_switch_list, head) { @@ -58,8 +59,10 @@ void pm_vt_switch_required(struct device *dev, bool required) } entry = kmalloc(sizeof(*entry), GFP_KERNEL); - if (!entry) + if (!entry) { + ret = -ENOMEM; goto out; + } entry->required = required; entry->dev = dev; @@ -67,6 +70,7 @@ void pm_vt_switch_required(struct device *dev, bool required) list_add(&entry->head, &pm_vt_switch_list); out: mutex_unlock(&vt_switch_mutex); + return ret; } EXPORT_SYMBOL(pm_vt_switch_required); -- cgit v1.2.3 From d3db87f89c71c34f4a6a0ee9de3dfab5eee18b22 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 9 Oct 2025 21:34:16 +0200 Subject: PM: hibernate: Rework message printing in swsusp_save() The messages printed by swsusp_save() are basically only useful for debug, so printing them every time a hibernation image is created at the "info" log level is not particularly useful. Also printing a message on a failing memory allocation is redundant. Use pm_deferred_pr_dbg() for printing those messages so they will only be printed when requested and the "deferred" variant is used because this code runs in a deeply atomic context (one CPU with interrupts off, no functional devices). Also drop the useless message printed when memory allocations fails. While at it, extend one of the messages in question so it is less cryptic. Signed-off-by: Rafael J. Wysocki [ rjw: Dropped a useless colon at the end of one of the messages ] Link: https://patch.msgid.link/10750389.nUPlyArG6x@rafael.j.wysocki --- kernel/power/snapshot.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 645f42e40478..0a946932d5c1 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -2110,22 +2110,20 @@ asmlinkage __visible int swsusp_save(void) { unsigned int nr_pages, nr_highmem; - pr_info("Creating image:\n"); + pm_deferred_pr_dbg("Creating image\n"); drain_local_pages(NULL); nr_pages = count_data_pages(); nr_highmem = count_highmem_pages(); - pr_info("Need to copy %u pages\n", nr_pages + nr_highmem); + pm_deferred_pr_dbg("Need to copy %u pages\n", nr_pages + nr_highmem); if (!enough_free_mem(nr_pages, nr_highmem)) { - pr_err("Not enough free memory\n"); + pm_deferred_pr_dbg("Not enough free memory for image creation\n"); return -ENOMEM; } - if (swsusp_alloc(©_bm, nr_pages, nr_highmem)) { - pr_err("Memory allocation failed\n"); + if (swsusp_alloc(©_bm, nr_pages, nr_highmem)) return -ENOMEM; - } /* * During allocating of suspend pagedir, new cold pages may appear. @@ -2144,7 +2142,8 @@ asmlinkage __visible int swsusp_save(void) nr_zero_pages = nr_pages - nr_copy_pages; nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE); - pr_info("Image created (%d pages copied, %d zero pages)\n", nr_copy_pages, nr_zero_pages); + pm_deferred_pr_dbg("Image created (%d pages copied, %d zero pages)\n", + nr_copy_pages, nr_zero_pages); return 0; } -- cgit v1.2.3 From e114e2eb7e85b5cc737ff5286cfe68a58caffeba Mon Sep 17 00:00:00 2001 From: Xueqin Luo Date: Tue, 21 Oct 2025 19:37:26 +0800 Subject: PM: hibernate: dynamically allocate crc->unc_len/unc for configurable threads Convert crc->unc_len and crc->unc from fixed-size arrays to dynamically allocated arrays, sized according to the actual number of threads selected at runtime. This removes the fixed limit imposed by CMP_THREADS. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/b5db63bb95729482d2649b12d3a11cb7547b7fcc.1761046167.git.luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki --- kernel/power/swap.c | 58 ++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 44 insertions(+), 14 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 0beff7eeaaba..f8c13f5672ec 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -585,10 +585,48 @@ 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; /* uncompressed lengths */ + unsigned char **unc; /* uncompressed data */ }; +static struct crc_data *alloc_crc_data(int nr_threads) +{ + struct crc_data *crc; + + crc = kzalloc(sizeof(*crc), GFP_KERNEL); + if (!crc) + return NULL; + + crc->unc = kcalloc(nr_threads, sizeof(*crc->unc), GFP_KERNEL); + if (!crc->unc) + goto err_free_crc; + + crc->unc_len = kcalloc(nr_threads, sizeof(*crc->unc_len), GFP_KERNEL); + if (!crc->unc_len) + goto err_free_unc; + + return crc; + +err_free_unc: + kfree(crc->unc); +err_free_crc: + kfree(crc); + return NULL; +} + +static void free_crc_data(struct crc_data *crc) +{ + if (!crc) + return; + + if (crc->thr) + kthread_stop(crc->thr); + + kfree(crc->unc_len); + kfree(crc->unc); + kfree(crc); +} + /* * CRC32 update function that runs in its own thread. */ @@ -719,7 +757,7 @@ static int save_compressed_image(struct swap_map_handle *handle, goto out_clean; } - crc = kzalloc(sizeof(*crc), GFP_KERNEL); + crc = alloc_crc_data(nr_threads); if (!crc) { pr_err("Failed to allocate crc\n"); ret = -ENOMEM; @@ -885,11 +923,7 @@ out_finish: out_clean: hib_finish_batch(&hb); - if (crc) { - if (crc->thr) - kthread_stop(crc->thr); - kfree(crc); - } + free_crc_data(crc); if (data) { for (thr = 0; thr < nr_threads; thr++) { if (data[thr].thr) @@ -1239,7 +1273,7 @@ static int load_compressed_image(struct swap_map_handle *handle, goto out_clean; } - crc = kzalloc(sizeof(*crc), GFP_KERNEL); + crc = alloc_crc_data(nr_threads); if (!crc) { pr_err("Failed to allocate crc\n"); ret = -ENOMEM; @@ -1506,11 +1540,7 @@ out_clean: hib_finish_batch(&hb); for (i = 0; i < ring_size; i++) free_page((unsigned long)page[i]); - if (crc) { - if (crc->thr) - kthread_stop(crc->thr); - kfree(crc); - } + free_crc_data(crc); if (data) { for (thr = 0; thr < nr_threads; thr++) { if (data[thr].thr) -- cgit v1.2.3 From 090bf5a0f40030f4ef294a3edb84c5e99b843c7f Mon Sep 17 00:00:00 2001 From: Xueqin Luo Date: Tue, 21 Oct 2025 19:37:27 +0800 Subject: PM: hibernate: make compression threads configurable MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The number of compression/decompression threads has a direct impact on hibernate image generation and resume latency. Using more threads can reduce overall resume time, but on systems with fewer CPU cores it may also introduce contention and reduce efficiency. Performance was evaluated on an 8-core ARM system, averaged over 10 runs: Threads Hibernate(s) Resume(s) -------------------------------- 3 12.14 18.86 4 12.28 17.48 5 11.09 16.77 6 11.08 16.44 With 5–6 threads, resume latency improves by approximately 12% compared to the default 3-thread configuration, with negligible impact on hibernate time. Introduce a new kernel parameter `hibernate_compression_threads=` that allows users and integrators to tune the number of compression/decompression threads at boot. This provides a way to balance performance and CPU utilization across a wide range of hardware without recompiling the kernel. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/f24b3ca6416e230a515a154ed4c121d72a7e05a6.1761046167.git.luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki --- kernel/power/swap.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index f8c13f5672ec..aa11576e92a9 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -519,8 +519,9 @@ static int swap_writer_finish(struct swap_map_handle *handle, CMP_HEADER, PAGE_SIZE) #define CMP_SIZE (CMP_PAGES * PAGE_SIZE) -/* Maximum number of threads for compression/decompression. */ -#define CMP_THREADS 3 +/* Default number of threads for compression/decompression. */ +#define CMP_THREADS 3 +static unsigned int hibernate_compression_threads = CMP_THREADS; /* Minimum/maximum number of pages for read buffering. */ #define CMP_MIN_RD_PAGES 1024 @@ -741,7 +742,7 @@ 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, hibernate_compression_threads); page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH); if (!page) { @@ -1257,7 +1258,7 @@ 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, hibernate_compression_threads); page = vmalloc_array(CMP_MAX_RD_PAGES, sizeof(*page)); if (!page) { @@ -1697,3 +1698,19 @@ static int __init swsusp_header_init(void) } core_initcall(swsusp_header_init); + +static int __init hibernate_compression_threads_setup(char *str) +{ + int rc = kstrtouint(str, 0, &hibernate_compression_threads); + + if (rc) + return rc; + + if (hibernate_compression_threads < 1) + hibernate_compression_threads = CMP_THREADS; + + return 1; + +} + +__setup("hibernate_compression_threads=", hibernate_compression_threads_setup); -- cgit v1.2.3 From ea358066ded351036cb8b69c424a05e223472a03 Mon Sep 17 00:00:00 2001 From: Xueqin Luo Date: Tue, 21 Oct 2025 19:37:28 +0800 Subject: PM: hibernate: add sysfs interface for hibernate_compression_threads Add a sysfs attribute `/sys/power/hibernate_compression_threads` to allow runtime configuration of the number of threads used for compressing and decompressing hibernation images. The new sysfs interface enables dynamic adjustment at runtime: # cat /sys/power/hibernate_compression_threads 3 # echo 4 > /sys/power/hibernate_compression_threads This change provides greater flexibility for debugging and performance tuning of hibernation without requiring a reboot. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/c68c62f97fabf32507b8794ad8c16cd22ee656ac.1761046167.git.luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki --- kernel/power/swap.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'kernel/power') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index aa11576e92a9..d173e276b494 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -1689,8 +1689,46 @@ int swsusp_unmark(void) } #endif +static ssize_t hibernate_compression_threads_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%d\n", hibernate_compression_threads); +} + +static ssize_t hibernate_compression_threads_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t n) +{ + unsigned long val; + + if (kstrtoul(buf, 0, &val)) + return -EINVAL; + + if (val < 1) + return -EINVAL; + + hibernate_compression_threads = val; + return n; +} +power_attr(hibernate_compression_threads); + +static struct attribute *g[] = { + &hibernate_compression_threads_attr.attr, + NULL, +}; + +static const struct attribute_group attr_group = { + .attrs = g, +}; + static int __init swsusp_header_init(void) { + int error; + + error = sysfs_create_group(power_kobj, &attr_group); + if (error) + return -ENOMEM; + swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL); if (!swsusp_header) panic("Could not allocate memory for swsusp_header\n"); -- cgit v1.2.3 From a10ad1b104024efe0a01d21ce7c08002cf4034c4 Mon Sep 17 00:00:00 2001 From: Riwen Lu Date: Thu, 13 Nov 2025 09:26:38 +0800 Subject: PM: suspend: Make pm_test delay interruptible by wakeup events Modify the suspend_test() function to allow the test delay to be interrupted by wakeup events. This improves the responsiveness of the system during suspend testing when wakeup events occur, allowing the suspend process to proceed without waiting for the full test delay to complete when wakeup events are detected. Additionally, using msleep() instead of mdelay() avoids potential soft lockup "CPU stuck" issues when long test delays are configured. Co-developed-by: xiongxin Signed-off-by: xiongxin Signed-off-by: Riwen Lu [ rjw: Changelog edits ] Link: https://patch.msgid.link/20251113012638.1362013-1-luriwen@kylinos.cn Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/power') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index b4ca17c2fecf..1c2f777da367 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -344,10 +344,14 @@ MODULE_PARM_DESC(pm_test_delay, static int suspend_test(int level) { #ifdef CONFIG_PM_DEBUG + int i; + if (pm_test_level == level) { pr_info("suspend debug: Waiting for %d second(s).\n", pm_test_delay); - mdelay(pm_test_delay * 1000); + for (i = 0; i < pm_test_delay && !pm_wakeup_pending(); i++) + msleep(1000); + return 1; } #endif /* !CONFIG_PM_DEBUG */ -- cgit v1.2.3