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From: Zhen Ni <zhen.ni@easystack.cn>
To: tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com
Cc: cgroups@vger.kernel.org, Zhen Ni <zhen.ni@easystack.cn>
Subject: [PATCH] cgroup: Simplify cgroup_disable loop given limited count
Date: Wed, 30 Jul 2025 16:10:15 +0800	[thread overview]
Message-ID: <20250730081015.910435-1-zhen.ni@easystack.cn> (raw)

This patch refactors the cgroup_disable loop in cgroup_disable() to
leverage the fact that OPT_FEATURE_COUNT can only be 0 or 1, making
the loop structure unnecessary complex.

Key insights:
- OPT_FEATURE_COUNT is defined as an enum value that is either:
  * 0 when CONFIG_PSI is disabled (no optional features)
  * 1 when CONFIG_PSI is enabled (only "pressure" feature)
- Therefore, the loop will either:
  * Run 0 times (when no features exist)
  * Run exactly 1 time (when only one feature exists)

Performance considerations:
- The change has no performance impact since the loop runs at most once

Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
---
 kernel/cgroup/cgroup.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index a723b7dc6e4e..71059b61b341 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6895,11 +6895,11 @@ static int __init cgroup_disable(char *str)
 		}
 
 		for (i = 0; i < OPT_FEATURE_COUNT; i++) {
-			if (strcmp(token, cgroup_opt_feature_names[i]))
-				continue;
-			cgroup_feature_disable_mask |= 1 << i;
-			pr_info("Disabling %s control group feature\n",
-				cgroup_opt_feature_names[i]);
+			if (!strcmp(token, cgroup_opt_feature_names[i])) {
+				cgroup_feature_disable_mask |= 1 << i;
+				pr_info("Disabling %s control group feature\n",
+					cgroup_opt_feature_names[i]);
+			}
 			break;
 		}
 	}
-- 
2.20.1


             reply	other threads:[~2025-07-30  8:15 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-30  8:10 Zhen Ni [this message]
2025-07-30  8:36 ` [PATCH] cgroup: Simplify cgroup_disable loop given limited count Michal Koutný

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