The items passed in the array pointed by the arg parameter
of IORING_REGISTER_IOWQ_MAX_WORKERS io_uring_register operation
carry certain semantics: they refer to different io-wq worker categories;
provide IO_WQ_* constants in the UAPI, so these categories can be referenced
in the user space code.
Suggested-by: Jens Axboe <axboe@xxxxxxxxx>
Complements: 2e480058ddc21ec5 ("io-wq: provide a way to limit max number of workers")
Signed-off-by: Eugene Syromiatnikov <esyr@xxxxxxxxxx>
---
v3:
- Constants are named in accordance with the suggestion, the internal enum
is no longer touched, BUILD_BUG_ON checks are added.
v2: https://lore.kernel.org/lkml/20210913104101.GA29616@xxxxxxxxxxxxxxxxx/
- IO_WQ_ACCT_NR is no longer exposed directly in UAPI, per Jens Axboe's
suggestion.
v1: https://lore.kernel.org/lkml/20210912122411.GA27679@xxxxxxxxxxxxxxxxx/
---
fs/io-wq.c | 5 +++++
include/uapi/linux/io_uring.h | 8 +++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 6c55362..3d21568 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -14,6 +14,7 @@
#include <linux/rculist_nulls.h>
#include <linux/cpu.h>
#include <linux/tracehook.h>
+#include <uapi/linux/io_uring.h>
#include "io-wq.h"
@@ -1287,6 +1288,10 @@ int io_wq_max_workers(struct io_wq *wq, int *new_count)
{
int i, node, prev = 0;
+ BUILD_BUG_ON((int) IO_WQ_ACCT_BOUND != (int) IO_WQ_BOUND);
+ BUILD_BUG_ON((int) IO_WQ_ACCT_UNBOUND != (int) IO_WQ_UNBOUND);
+ BUILD_BUG_ON((int) IO_WQ_ACCT_NR != 2);
+
for (i = 0; i < 2; i++) {
if (new_count[i] > task_rlimit(current, RLIMIT_NPROC))
new_count[i] = task_rlimit(current, RLIMIT_NPROC);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 59ef351..b270a07 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -317,13 +317,19 @@ enum {
IORING_REGISTER_IOWQ_AFF = 17,
IORING_UNREGISTER_IOWQ_AFF = 18,
- /* set/get max number of workers */
+ /* set/get max number of io-wq workers */
IORING_REGISTER_IOWQ_MAX_WORKERS = 19,
/* this goes last */
IORING_REGISTER_LAST
};
+/* io-wq worker categories */
+enum {
+ IO_WQ_BOUND,
+ IO_WQ_UNBOUND,
+};
+
/* deprecated, see struct io_uring_rsrc_update */
struct io_uring_files_update {
__u32 offset;
--
2.1.4
