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Wong" , Alexander Viro , Christian Brauner , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Chandan Babu R , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , kernel-team@fb.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH 01/10] fs: turn inode ctime fields into a single ktime_t Message-ID: References: <20240702101902.qcx73xgae2sqoso7@quack3> <958080f6de517cf9d0a1994e3ca500f23599ca33.camel@kernel.org> <09ad82419eb78a2f81dda5dca9caae10663a2a19.camel@kernel.org> <4ec1fbdc6568e16da40f41789081805e764fd83e.camel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ec1fbdc6568e16da40f41789081805e764fd83e.camel@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: B815540003 X-Stat-Signature: jqfqc19xzbyk3rdsuuh9x7yo6xah7qo7 X-HE-Tag: 1719984424-313044 X-HE-Meta: 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 gQo0F+O5 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 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 Tue, Jul 02, 2024 at 11:58:02AM -0400, Jeff Layton wrote: > Yeah, mostly. We shrink struct inode by 8 bytes with that patch, and we > (probably) get a better cache footprint, since i_version ends up in the > same cacheline as the ctime. That's really a separate issue though, so > I'm not too worked up about dropping that patch. > > As a bonus, leaving it split across separate fields means that we can > use unused bits in the nsec field for the flag, so we don't need to > sacrifice any timestamp granularity either. > > I've got a draft rework that does this that I'm testing now. Assuming > it works OK, I'll resend in a few days. So while shrinking the inodes sounds nice, the tradeoff to have to check all timestamps from disk / the server for validity doesn't sound as positive. So I'm glade we're avoiding this at least for.