Hi Sandeep,
On 2025/5/2 02:30, Sandeep Dhavale wrote:
Currently, when EROFS is built with per-CPU workers, the workers are
started and CPU hotplug hooks are registered during module initialization.
This leads to unnecessary worker start/stop cycles during CPU hotplug
events, particularly on Android devices that frequently suspend and resume.
This change defers the initialization of per-CPU workers and the
registration of CPU hotplug hooks until the first EROFS mount. This
ensures that these resources are only allocated and managed when EROFS is
actually in use.
The tear down of per-CPU workers and unregistration of CPU hotplug hooks
still occurs during z_erofs_exit_subsystem(), but only if they were
initialized.
Signed-off-by: Sandeep Dhavale <dhav...@google.com>
---
v4:
https://lore.kernel.org/linux-erofs/20250423061023.131354-1-dhav...@google.com/
Changes since v4:
- remove redundant blank line as suggested by Gao
- add a log for failure path as suggested by Chao
- also add success log which will help in case there was a failure
before, else stale failure log could cause unnecessary concern
fs/erofs/zdata.c | 65 ++++++++++++++++++++++++++++++++++++------------
1 file changed, 49 insertions(+), 16 deletions(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 0671184d9cf1..a5d3aef319b2 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -291,6 +291,9 @@ static struct workqueue_struct *z_erofs_workqueue
__read_mostly;
#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
static struct kthread_worker __rcu **z_erofs_pcpu_workers;
+static atomic_t erofs_percpu_workers_initialized = ATOMIC_INIT(0);
+static int erofs_cpu_hotplug_init(void);
+static void erofs_cpu_hotplug_destroy(void);
We could move downwards to avoid those forward declarations;
static void erofs_destroy_percpu_workers(void)
{
@@ -336,9 +339,45 @@ static int erofs_init_percpu_workers(void)
}
return 0;
}
+
+static int z_erofs_init_pcpu_workers(void)
How about passing in `struct super_block *` here?
Since print messages are introduced, it's much better to
know which instance caused the error/info.
+{
+ int err;
+
+ if (atomic_xchg(&erofs_percpu_workers_initialized, 1))
+ return 0;
+
+ err = erofs_init_percpu_workers();
+ if (err) {
+ erofs_err(NULL, "per-cpu workers: failed to allocate.");
+ goto err_init_percpu_workers;
+ }
+
+ err = erofs_cpu_hotplug_init();
+ if (err < 0) {
+ erofs_err(NULL, "per-cpu workers: failed CPU hotplug init.");
+ goto err_cpuhp_init;
+ }
+ erofs_info(NULL, "initialized per-cpu workers successfully.");
Otherwise it looks good to me know.
Thanks,
Gao Xiang
