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From: mengensun88@gmail.com
To: dhowells@redhat.com
Cc: jarkko@kernel.org, jmorris@namei.org, keyrings@vger.kernel.org,
	yuehongwu@tencent.com, MengEn Sun <mengensun@tencent.com>
Subject: [PATCH] keys: Add cond_resched to key_gc_unused_keys()
Date: Wed, 27 Nov 2024 11:52:41 +0800	[thread overview]
Message-ID: <1732679561-22967-1-git-send-email-mengensun@tencent.com> (raw)

From: MengEn Sun <mengensun@tencent.com>

When running the follow test:
while :
do
    stress-ng --key=64 --key-ops=1000
done

We used the bcc tools funclatency to measure the execution
latency of key_gc_unused_keys(), and the results are as
follows:

funclatency key_gc_unused_keys.constprop.5 -i 1 -m
msecs               : count
    0 -> 1          : 0
    2 -> 3          : 0
    4 -> 7          : 0
    8 -> 15         : 0
   16 -> 31         : 0
   32 -> 63         : 0
   64 -> 127        : 1

It seems that key_gc_unused_keys() takes a long time to
execute, and there are no scheduling points in this function,
which may harm latency-sensitive services.

Therefore, we have added a scheduling point to this function.

Reviewed-by: YueHong Wu <yuehongwu@tencent.com>
Signed-off-by: MengEn Sun <mengensun@tencent.com>
---
 security/keys/gc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/security/keys/gc.c b/security/keys/gc.c
index 7d687b0..14e4f1c 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -165,6 +165,7 @@ static noinline void key_gc_unused_keys(struct list_head *keys)
 
 		memzero_explicit(key, sizeof(*key));
 		kmem_cache_free(key_jar, key);
+		cond_resched();
 	}
 }
 
-- 
1.8.3.1


             reply	other threads:[~2024-11-27  3:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-27  3:52 mengensun88 [this message]
2024-11-30  2:46 ` [PATCH] keys: Add cond_resched to key_gc_unused_keys() Jarkko Sakkinen
2024-12-06  7:46   ` MengEn Sun

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