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AJvYcCWoVf64b8lRv0hFRSN9/vo+ohQjbYiKJMRjJ+uVDRBZHgtl0r5EfTfuSEnnq50+nXz7Io3py3TaXQ==@kvack.org X-Gm-Message-State: AOJu0YzWOkuTcK35aSGvjdb/1tRPyBhPG9zvLBT5DkZL66113cD2vZqH nHEKAyuknfbG8S10lxEgZjg5w5I++iTD7kkTQjCSSNwAxfJmgRD52j9Z3SKjCPAiAzBGy1b70D5 OB0ndkmboHBJcA8LtaCJ7cmBfL7OqkeP+6cE= X-Google-Smtp-Source: AGHT+IHWtZ8oBZ/r75IG/ZCzOt2Io2yL14++IpNnUCKri/jsmh7LErkKNbEwqZih9dC/IIe59HK21E10WSAVnPAmuFA= X-Received: by 2002:a17:907:1b20:b0:a86:9c41:cfc1 with SMTP id a640c23a62f3a-a90293dab74mr710886366b.8.1726255059557; Fri, 13 Sep 2024 12:17:39 -0700 (PDT) MIME-Version: 1.0 References: <20240913-mgtime-v7-0-92d4020e3b00@kernel.org> <20240913-mgtime-v7-1-92d4020e3b00@kernel.org> <8756a43fe0b7c3f418b351adb05e7a146d33bdfe.camel@kernel.org> In-Reply-To: <8756a43fe0b7c3f418b351adb05e7a146d33bdfe.camel@kernel.org> From: John Stultz Date: Fri, 13 Sep 2024 12:17:26 -0700 Message-ID: Subject: Re: [PATCH v7 01/11] timekeeping: move multigrain timestamp floor handling into timekeeper To: Jeff Layton Cc: Thomas Gleixner , Stephen Boyd , Alexander Viro , Christian Brauner , Jan Kara , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Chandan Babu R , "Darrick J. Wong" , "Theodore Ts'o" , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , Chuck Lever , Vadim Fedorenko , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Queue-Id: 8BDF220007 X-Rspamd-Server: rspam01 X-Stat-Signature: wyubx5znh9ztdn6pbofthqh9e3ftywtz X-HE-Tag: 1726255061-960891 X-HE-Meta: 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 HABLL1HG UcKHmDDqj+rQ0hEjR3kjAr4mRVbg/8S16VjoXAmPW6nwUjlr5CebsZGBfoUthXD1ARUXQKnaCf8ZpbnQ7SP6H3AwdXNfMx041zDKhHbhUNkdrvUZBLshzEtr5HF7JhUuUIzqSK0rGlMoC3I6hsIi6Zs771h2pclYlF0byTB4MTz8/3OuXDfVPT3uN7RW6MeC28+BmjF9foZkbMyJomaV0MQZyy1S/QXofIAz+BOA80v8/Esp7x1EzNtZS6mb8vBMnM3kyGlawTxEOQfqLuTllRv6hvZf7Xkp6U+9gHFDWnwLbi/N5lEV37fefapsvyocHNLVLi0MyxyGW/FWIK5+GHK1BOpIphUuHwWX7 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Sep 13, 2024 at 12:06=E2=80=AFPM Jeff Layton w= rote: > On Fri, 2024-09-13 at 11:59 -0700, John Stultz wrote: > > > +/** > > > + * ktime_get_real_ts64_mg - attempt to update floor value and return= result > > > + * @ts: pointer to the timespec to be set > > > + * @cookie: opaque cookie from earlier call to ktime_get_coarse_r= eal_ts64_mg() > > > + * > > > + * Get a current monotonic fine-grained time value and attempt to sw= ap > > > + * it into the floor using @cookie as the "old" value. @ts will be > > > + * filled with the resulting floor value, regardless of the outcome = of > > > + * the swap. > > > > I'd add more detail here to clarify that this can return a coarse > > floor value if the cookie is stale. > > > > Sure, or I can just drop the cookie, if that's better. That seems like the simpler approach, but I don't have a sense of the actual performance impact, so I'll leave that decision to you. thanks -john