From: Oleg Nesterov <oleg@redhat.com>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: linux-trace-kernel@vger.kernel.org, rostedt@goodmis.org,
mhiramat@kernel.org, peterz@infradead.org, mingo@redhat.com,
bpf@vger.kernel.org, jolsa@kernel.org, paulmck@kernel.org,
clm@meta.com
Subject: Re: [PATCH 04/12] uprobes: revamp uprobe refcounting and lifetime management
Date: Tue, 25 Jun 2024 16:44:09 +0200 [thread overview]
Message-ID: <20240625144409.GA21366@redhat.com> (raw)
In-Reply-To: <20240625002144.3485799-5-andrii@kernel.org>
Again, I'll try to read (at least this) patch later this week,
just one cosmetic nit for now...
On 06/24, Andrii Nakryiko wrote:
>
> + * UPROBE_REFCNT_GET constant is chosen such that it will *increment both*
> + * epoch and refcnt parts atomically with one atomic_add().
> + * UPROBE_REFCNT_PUT is chosen such that it will *decrement* refcnt part and
> + * *increment* epoch part.
> + */
> +#define UPROBE_REFCNT_GET ((1LL << 32) | 1LL)
> +#define UPROBE_REFCNT_PUT (0xffffffffLL)
How about
#define UPROBE_REFCNT_GET ((1ULL << 32) + 1ULL)
#define UPROBE_REFCNT_PUT ((1ULL << 32) - 1ULL)
? this makes them symmetrical and makes it clear why
atomic64_add(UPROBE_REFCNT_PUT) works as described in the comment.
Feel free to ignore if you don't like it.
Oleg.
next prev parent reply other threads:[~2024-06-25 14:45 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-25 0:21 [PATCH 00/12] uprobes: add batched register/unregister APIs and per-CPU RW semaphore Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 01/12] uprobes: update outdated comment Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 02/12] uprobes: grab write mmap lock in unapply_uprobe() Andrii Nakryiko
2024-06-25 1:29 ` Masami Hiramatsu
2024-06-25 14:49 ` Oleg Nesterov
2024-06-25 17:37 ` Andrii Nakryiko
2024-06-25 19:07 ` Oleg Nesterov
2024-06-26 16:38 ` Andrii Nakryiko
2024-06-25 10:50 ` Oleg Nesterov
2024-06-25 0:21 ` [PATCH 03/12] uprobes: simplify error handling for alloc_uprobe() Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 04/12] uprobes: revamp uprobe refcounting and lifetime management Andrii Nakryiko
2024-06-25 14:44 ` Oleg Nesterov [this message]
2024-06-25 17:30 ` Andrii Nakryiko
2024-06-26 6:02 ` kernel test robot
2024-06-26 16:39 ` Andrii Nakryiko
2024-06-27 2:29 ` Masami Hiramatsu
2024-06-27 16:43 ` Andrii Nakryiko
2024-07-01 21:59 ` Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 05/12] uprobes: move offset and ref_ctr_offset into uprobe_consumer Andrii Nakryiko
2024-06-27 3:06 ` Masami Hiramatsu
2024-06-25 0:21 ` [PATCH 06/12] uprobes: add batch uprobe register/unregister APIs Andrii Nakryiko
2024-06-26 11:27 ` Jiri Olsa
2024-06-26 16:44 ` Andrii Nakryiko
2024-06-27 13:04 ` Masami Hiramatsu
2024-06-27 16:47 ` Andrii Nakryiko
2024-06-28 6:28 ` Masami Hiramatsu
2024-06-28 16:34 ` Andrii Nakryiko
2024-06-29 23:30 ` Masami Hiramatsu
2024-07-01 17:55 ` Andrii Nakryiko
2024-07-01 22:15 ` Andrii Nakryiko
2024-07-02 1:01 ` Masami Hiramatsu
2024-07-02 1:34 ` Andrii Nakryiko
2024-07-02 15:19 ` Masami Hiramatsu
2024-07-02 16:53 ` Steven Rostedt
2024-07-02 21:23 ` Andrii Nakryiko
2024-07-02 23:16 ` Masami Hiramatsu
2024-06-25 0:21 ` [PATCH 07/12] uprobes: inline alloc_uprobe() logic into __uprobe_register() Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 08/12] uprobes: split uprobe allocation and uprobes_tree insertion steps Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 09/12] uprobes: batch uprobes_treelock during registration Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 10/12] uprobes: improve lock batching for uprobe_unregister_batch Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 11/12] uprobes,bpf: switch to batch uprobe APIs for BPF multi-uprobes Andrii Nakryiko
2024-06-25 0:21 ` [PATCH 12/12] uprobes: switch uprobes_treelock to per-CPU RW semaphore Andrii Nakryiko
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