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From: Oleg Nesterov <oleg@redhat.com>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: linux-trace-kernel@vger.kernel.org, peterz@infradead.org,
	rostedt@goodmis.org, mhiramat@kernel.org, bpf@vger.kernel.org,
	linux-kernel@vger.kernel.org, jolsa@kernel.org,
	paulmck@kernel.org
Subject: Re: [PATCH v2 2/6] uprobes: protected uprobe lifetime with SRCU
Date: Thu, 8 Aug 2024 12:20:23 +0200	[thread overview]
Message-ID: <20240808102022.GB8020@redhat.com> (raw)
In-Reply-To: <20240808002118.918105-3-andrii@kernel.org>

On 08/07, Andrii Nakryiko wrote:
>
>  struct uprobe {
> -	struct rb_node		rb_node;	/* node in the rb tree */
> +	union {
> +		struct rb_node		rb_node;	/* node in the rb tree */
> +		struct rcu_head		rcu;		/* mutually exclusive with rb_node */

Andrii, I am sorry.

I suggested this in reply to 3/8 before I read
[PATCH 7/8] uprobes: perform lockless SRCU-protected uprobes_tree lookup

I have no idea if rb_erase() is rcu-safe or not, but this union certainly
doesn't look right if we use rb_find_rcu/etc.

Yes, this version doesn't include the SRCU-protected uprobes_tree changes,
but still...

Oleg.


  reply	other threads:[~2024-08-08 10:20 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-08  0:21 [PATCH v2 0/6] uprobes: RCU-protected hot path optimizations Andrii Nakryiko
2024-08-08  0:21 ` [PATCH v2 1/6] uprobes: revamp uprobe refcounting and lifetime management Andrii Nakryiko
2024-08-08  0:21 ` [PATCH v2 2/6] uprobes: protected uprobe lifetime with SRCU Andrii Nakryiko
2024-08-08 10:20   ` Oleg Nesterov [this message]
2024-08-08 16:58     ` Andrii Nakryiko
2024-08-08 17:51       ` Andrii Nakryiko
2024-08-08  0:21 ` [PATCH v2 3/6] uprobes: get rid of enum uprobe_filter_ctx in uprobe filter callbacks Andrii Nakryiko
2024-08-08  0:21 ` [PATCH v2 4/6] uprobes: travers uprobe's consumer list locklessly under SRCU protection Andrii Nakryiko
2024-08-08 14:40   ` Oleg Nesterov
2024-08-08 17:50     ` Andrii Nakryiko
2024-08-08  0:21 ` [PATCH v2 5/6] perf/uprobe: split uprobe_unregister() Andrii Nakryiko
2024-08-08  0:21 ` [PATCH v2 6/6] uprobes: switch to RCU Tasks Trace flavor for better performance Andrii Nakryiko

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