From: Andreas Hindborg <a.hindborg@kernel•org>
To: "FUJITA Tomonori" <fujita.tomonori@gmail•com>
Cc: <linux-kernel@vger•kernel.org>, <daniel.almeida@collabora•com>,
<boqun.feng@gmail•com>, <gary@garyguo•net>, <me@kloenk•dev>,
<rust-for-linux@vger•kernel.org>, <netdev@vger•kernel.org>,
<andrew@lunn•ch>, <hkallweit1@gmail•com>, <tmgross@umich•edu>,
<ojeda@kernel•org>, <alex.gaynor@gmail•com>,
<bjorn3_gh@protonmail•com>, <benno.lossin@proton•me>,
<a.hindborg@samsung•com>, <aliceryhl@google•com>,
<anna-maria@linutronix•de>, <frederic@kernel•org>,
<tglx@linutronix•de>, <arnd@arndb•de>, <jstultz@google•com>,
<sboyd@kernel•org>, <mingo@redhat•com>, <peterz@infradead•org>,
<juri.lelli@redhat•com>, <vincent.guittot@linaro•org>,
<dietmar.eggemann@arm•com>, <rostedt@goodmis•org>,
<bsegall@google•com>, <mgorman@suse•de>, <vschneid@redhat•com>,
<tgunders@redhat•com>, <david.laight.linux@gmail•com>
Subject: Re: [PATCH v11 4/8] rust: time: Introduce Instant type
Date: Thu, 03 Apr 2025 12:41:52 +0200 [thread overview]
Message-ID: <87cydtv85r.fsf@kernel.org> (raw)
In-Reply-To: <20250403.134038.2188356790179825602.fujita.tomonori@gmail.com> (FUJITA Tomonori's message of "Thu, 03 Apr 2025 13:40:38 +0900")
"FUJITA Tomonori" <fujita.tomonori@gmail•com> writes:
> On Sat, 22 Mar 2025 14:58:16 +0100
> Andreas Hindborg <a.hindborg@kernel•org> wrote:
>
>> FUJITA Tomonori <fujita.tomonori@gmail•com> writes:
>>
>>> Introduce a type representing a specific point in time. We could use
>>> the Ktime type but C's ktime_t is used for both timestamp and
>>> timedelta. To avoid confusion, introduce a new Instant type for
>>> timestamp.
>>>
>>> Rename Ktime to Instant and modify their methods for timestamp.
>>>
>>> Implement the subtraction operator for Instant:
>>>
>>> Delta = Instant A - Instant B
>>>
>>> Tested-by: Daniel Almeida <daniel.almeida@collabora•com>
>>> Reviewed-by: Boqun Feng <boqun.feng@gmail•com>
>>> Reviewed-by: Gary Guo <gary@garyguo•net>
>>> Reviewed-by: Fiona Behrens <me@kloenk•dev>
>>> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail•com>
>>
>>
>> Reviewed-by: Andreas Hindborg <a.hindborg@kernel•org>
>>
>>
>> As Boqun mentioned, we should make this generic over `ClockId` when the
>> hrtimer patches land.
>
> Seems that I overlooked his mail. Can you give me a pointer?
>
> I assume that you want the Instance type to vary depending on the
> clock source.
Yea, basically it is only okay to subtract instants if they are derived
from the same clock source. Boqun suggested here [1] before hrtimer
patches landed I think.
At any rate, now we have `kernel::time::ClockId`. It is an enum though,
so I am not sure how to go about it in practice. But we would want
`Instant<RealTime> - Instant<BootTime>` to give a compiler error.
Best regards,
Andreas Hindborg
[1] https://lore.kernel.org/all/ZxwFyl0xIje5gv7J@Boquns-Mac-mini.local
next prev parent reply other threads:[~2025-04-03 10:42 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-20 7:06 [PATCH v11 0/8] rust: Add IO polling FUJITA Tomonori
2025-02-20 7:06 ` [PATCH v11 1/8] sched/core: Add __might_sleep_precision() FUJITA Tomonori
2025-02-24 1:40 ` FUJITA Tomonori
2025-02-20 7:06 ` [PATCH v11 2/8] rust: time: Add PartialEq/Eq/PartialOrd/Ord trait to Ktime FUJITA Tomonori
2025-03-22 8:51 ` Andreas Hindborg
2025-02-20 7:06 ` [PATCH v11 3/8] rust: time: Introduce Delta type FUJITA Tomonori
2025-03-22 8:50 ` Andreas Hindborg
2025-02-20 7:06 ` [PATCH v11 4/8] rust: time: Introduce Instant type FUJITA Tomonori
2025-03-22 13:58 ` Andreas Hindborg
2025-04-03 4:40 ` FUJITA Tomonori
2025-04-03 10:41 ` Andreas Hindborg [this message]
2025-04-03 12:23 ` FUJITA Tomonori
2025-02-20 7:06 ` [PATCH v11 5/8] rust: time: Add wrapper for fsleep() function FUJITA Tomonori
2025-03-21 22:05 ` Frederic Weisbecker
2025-03-22 1:24 ` FUJITA Tomonori
2025-03-22 14:15 ` Andreas Hindborg
2025-03-22 14:10 ` Andreas Hindborg
2025-02-20 7:06 ` [PATCH v11 6/8] MAINTAINERS: rust: Add new sections for DELAY/SLEEP and TIMEKEEPING API FUJITA Tomonori
2025-03-20 19:05 ` Boqun Feng
2025-03-21 19:18 ` Andreas Hindborg
2025-03-21 20:38 ` Thomas Gleixner
2025-03-21 21:00 ` Boqun Feng
2025-03-22 2:07 ` FUJITA Tomonori
2025-03-22 12:57 ` Boqun Feng
2025-03-22 22:40 ` Andreas Hindborg
2025-03-31 14:03 ` Boqun Feng
2025-03-31 19:43 ` Andreas Hindborg
2025-04-03 8:18 ` FUJITA Tomonori
2025-04-03 10:54 ` Andreas Hindborg
2025-04-03 12:57 ` FUJITA Tomonori
2025-04-04 16:40 ` Boqun Feng
2025-04-02 14:16 ` FUJITA Tomonori
2025-04-02 16:29 ` Boqun Feng
2025-04-02 23:03 ` FUJITA Tomonori
2025-04-03 0:51 ` Boqun Feng
2025-04-03 3:02 ` FUJITA Tomonori
2025-04-03 3:17 ` Boqun Feng
2025-02-20 7:06 ` [PATCH v11 7/8] rust: Add read_poll_timeout functions FUJITA Tomonori
2025-02-20 15:04 ` Fiona Behrens
2025-02-21 11:20 ` FUJITA Tomonori
2025-03-22 16:02 ` Andreas Hindborg
2025-08-11 1:53 ` FUJITA Tomonori
2025-08-11 9:42 ` Andreas Hindborg
2025-08-14 5:53 ` FUJITA Tomonori
2025-07-28 12:44 ` Daniel Almeida
2025-07-28 12:52 ` FUJITA Tomonori
2025-07-28 12:57 ` Danilo Krummrich
2025-07-28 13:08 ` FUJITA Tomonori
2025-07-28 13:15 ` Danilo Krummrich
2025-07-28 14:13 ` Daniel Almeida
2025-07-28 14:30 ` Danilo Krummrich
2025-07-28 13:13 ` Danilo Krummrich
2025-08-02 1:42 ` FUJITA Tomonori
2025-08-02 11:06 ` Danilo Krummrich
2025-08-05 13:37 ` FUJITA Tomonori
2025-08-05 13:48 ` Danilo Krummrich
2025-08-05 13:53 ` Andrew Lunn
2025-08-05 14:03 ` Danilo Krummrich
2025-08-05 14:01 ` Daniel Almeida
2025-08-05 14:19 ` Danilo Krummrich
2025-02-20 7:06 ` [PATCH v11 8/8] net: phy: qt2025: Wait until PHY becomes ready FUJITA Tomonori
2025-02-27 17:29 ` [PATCH v11 0/8] rust: Add IO polling Daniel Almeida
2025-02-27 23:05 ` FUJITA Tomonori
2025-03-20 19:04 ` Boqun Feng
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