Messages in this thread | | | Date | Sun, 8 Oct 2023 19:10:01 +0800 | Subject | Re: [PATCH 2/3] delayacct: convert task->delays to a object | From | brookxu <> |
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在 2023/10/8 18:58, Peter Zijlstra 写道: > On Sun, Oct 08, 2023 at 06:49:37PM +0800, brookxu.cn wrote: >> From: Chunguang Xu <chunguang.xu@shopee.com> >> >> Since in some scenarios we still want to get the task delayacct >> through taskstats, so commit <0cd7c741f01de> introduces a sysctl to > This is not the canonical way to reference a commit. > >> enable it dynamically. However, since task->delays is allocated >> during fork(), task->delays will not be reallocated when delayacct >> is enabled later. This will make we cannot get the delayacct of old >> tasks, but the new tasks cans. This can easily lead to confusion. >> Therefore, try to workaround this issue by convert task->delays to >> an object. > And grow task_struct for no reason? I think not. > >> diff --git a/include/linux/sched.h b/include/linux/sched.h >> index 77f01ac385f7..5cc78184a31f 100644 >> --- a/include/linux/sched.h >> +++ b/include/linux/sched.h >> @@ -37,6 +37,7 @@ >> #include <linux/kcsan.h> >> #include <linux/rv.h> >> #include <linux/livepatch_sched.h> >> +#include <linux/delayacct.h> >> #include <asm/kmap_size.h> >> >> /* task_struct member predeclarations (sorted alphabetically): */ >> @@ -1331,7 +1332,7 @@ struct task_struct { >> struct page_frag task_frag; >> >> #ifdef CONFIG_TASK_DELAY_ACCT >> - struct task_delay_info *delays; >> + struct task_delay_info delays; >> #endif > Yeah, no. Yes, this way will increase about 80 bytes for task_struct, about 0.85% of size of task_struct, I think this just like sched_statistics, so that can better support dynamically enable through sysctl.
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