This adds a new flag, PF_USER_WORKER, that's used for behavior common to
to both PF_IO_WORKER and users like vhost which will use a new helper
instead of create_io_thread because they require different behavior for
operations like signal handling.
The common behavior PF_USER_WORKER covers is the vm reclaim handling.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
include/linux/sched.h | 1 +
include/linux/sched/task.h | 3 ++-
kernel/fork.c | 4 ++++
mm/vmscan.c | 4 ++--
4 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c46f3a63b758..d7cd2037430b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1701,6 +1701,7 @@ extern struct pid *cad_pid;
#define PF_MEMALLOC 0x00000800 /* Allocating memory */
#define PF_NPROC_EXCEEDED 0x00001000 /* set_user() noticed that RLIMIT_NPROC was exceeded */
#define PF_USED_MATH 0x00002000 /* If unset the fpu must be initialized before use */
+#define PF_USER_WORKER 0x00004000 /* Kernel thread cloned from userspace thread */
#define PF_NOFREEZE 0x00008000 /* This thread should not be frozen */
#define PF_FROZEN 0x00010000 /* Frozen for system suspend */
#define PF_KSWAPD 0x00020000 /* I am kswapd */
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index b0a9d6c75bcc..9e20fa18c41f 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -18,7 +18,8 @@ struct css_set;
/* All the bits taken by the old clone syscall. */
#define CLONE_LEGACY_FLAGS 0xffffffffULL
-#define USER_WORKER_IO BIT(0)
+#define USER_WORKER BIT(0)
+#define USER_WORKER_IO BIT(1)
struct kernel_clone_args {
u64 flags;
diff --git a/kernel/fork.c b/kernel/fork.c
index 49fedb79925b..604c7f3cdde8 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2074,6 +2074,10 @@ static __latent_entropy struct task_struct *copy_process(
p->flags &= ~PF_KTHREAD;
if (args->kthread)
p->flags |= PF_KTHREAD;
+
+ if (args->worker_flags & USER_WORKER)
+ p->flags |= PF_USER_WORKER;
+
if (args->worker_flags & USER_WORKER_IO) {
/*
* Mark us an IO worker, and block any signal that isn't
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f7d9a683e3a7..6d771d8a3a4a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1047,12 +1047,12 @@ void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason)
DEFINE_WAIT(wait);
/*
- * Do not throttle IO workers, kthreads other than kswapd or
+ * Do not throttle user workers, kthreads other than kswapd or
* workqueues. They may be required for reclaim to make
* forward progress (e.g. journalling workqueues or kthreads).
*/
if (!current_is_kswapd() &&
- current->flags & (PF_IO_WORKER|PF_KTHREAD)) {
+ current->flags & (PF_USER_WORKER|PF_KTHREAD)) {
cond_resched();
return;
}
--
2.25.1
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