systemd/backport-psi-util-fix-error-handling.patch
zhaoxiaohu 9b963cce2e psi-util: fix error handling
Signed-off-by: zhaoxiaohu <zhaoxiaohu@kuaishou.com>
2024-12-04 15:43:40 +08:00

61 lines
2.2 KiB
Diff

From 90ec8ebe33ec72ed6d9f451de9443d67dd351d72 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 27 Feb 2023 19:02:41 +0100
Subject: [PATCH] psi-util: fix error handling
We checked ERRNO_IS_NOT_SUPPORTED on a possible positive non-error code,
which isn't right.
Fix that. Also add caching, since we are about to call this more often.
Reference: https://github.com/systemd/systemd/pull/26610/commits/1ea90a9d409999159345ad8e193f7ef4cc7f634d
Signed-off-by: zhaoxiaohu <zhaoxiaohu@kuaishou.com>
Signed-off-by: yuwang <yuwang@kuaishou.com>
---
src/shared/psi-util.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/src/shared/psi-util.c b/src/shared/psi-util.c
index 009095e..9045ae2 100644
--- a/src/shared/psi-util.c
+++ b/src/shared/psi-util.c
@@ -106,20 +106,25 @@ int read_resource_pressure(const char *path, PressureType type, ResourcePressure
}
int is_pressure_supported(void) {
+ static thread_local int cached = -1;
const char *p;
+ int r;
- /* The pressure files, both under /proc and in cgroups, will exist
- * even if the kernel has PSI support disabled; we have to read
- * the file to make sure it doesn't return -EOPNOTSUPP */
- FOREACH_STRING(p, "/proc/pressure/cpu", "/proc/pressure/io", "/proc/pressure/memory") {
- int r;
+ /* The pressure files, both under /proc/ and in cgroups, will exist even if the kernel has PSI
+ * support disabled; we have to read the file to make sure it doesn't return -EOPNOTSUPP */
+ if (cached >= 0)
+ return cached;
+
+ FOREACH_STRING(p, "/proc/pressure/cpu", "/proc/pressure/io", "/proc/pressure/memory") {
r = read_virtual_file(p, 0, NULL, NULL);
- if (r == -ENOENT || ERRNO_IS_NOT_SUPPORTED(r))
- return 0;
- if (r < 0)
+ if (r < 0) {
+ if (r == -ENOENT || ERRNO_IS_NOT_SUPPORTED(r))
+ return (cached = false);
+
return r;
+ }
}
- return 1;
+ return (cached = true);
}
--
2.33.0