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AJvYcCWMf2lNvpy8QHzANbURHL54O9RTWnUXGdKTv4Zzp0XXT1dvag1ITfl/QMpnVY9NzEUECPNhM4KjbQ==@kvack.org X-Gm-Message-State: AOJu0YyRzrlFFC804MuWFRZylorfARkeKYK9YeHN7tAB984uFPAiJ48q SL8SFnotG3WINr/o5rYS6G/37CqYkW4qjWz6KRcwA50w2eVDvnSwq+q5MFZtoZDUBAlFMJRuCwU pB5J+HFsu3IZAP73i6uW596nAp2I= X-Google-Smtp-Source: AGHT+IHdqoConUqClj8wLIM0mBnQdxHrbtF0Di+KOTfg36XQ9fCzKrtjZchTS75uFzJMILm9d1Yqc4hTdgQdLeKqdac= X-Received: by 2002:a2e:b88e:0:b0:2fb:59dc:735a with SMTP id 38308e7fff4ca-2ff607494aemr69833731fa.41.1732039666148; Tue, 19 Nov 2024 10:07:46 -0800 (PST) MIME-Version: 1.0 References: <20241119094555.660666-1-mjguzik@gmail.com> <20241119175355.GB3484088@mit.edu> In-Reply-To: <20241119175355.GB3484088@mit.edu> From: Mateusz Guzik Date: Tue, 19 Nov 2024 19:07:33 +0100 Message-ID: Subject: Re: [PATCH v2 0/3] symlink length caching To: "Theodore Ts'o" Cc: brauner@kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, hughd@google.com, linux-ext4@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: c1fmyx9oid3ngrxe8jrij119xgahep3k X-Rspam-User: X-Rspamd-Queue-Id: 793A7180012 X-Rspamd-Server: rspam02 X-HE-Tag: 1732039632-178823 X-HE-Meta: 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 PDnuHbdS W8WN1tOUMECs3ysEIUll/nm38rbt1vm38tYRJYiwK4IKULoQeH3jKaMafHUYInAsdPr2fk4MmrMzqz/d7+ncGnhMZHl86/BV0w/xLCImMQiGhGagwhDkw2lQ3JgnllRkhLOrV5MeEJjDZxEt2fs8x1H749ldNuJ3itUyJjOzgWnlmMm7T8OISp5ipv1thEKv7BdRcrl/kxGkXXlHoE6WW9i58kLDRZ6f6qifsj61I9eHSeQH4xvuBTUgskJnUVq9S0/GBhMh+LUaAzzNOv4BV0LujTUd2X61moYjOm04tKCdvFQTlP3TyWv4BtFmY+Sv+kO5RiI9N74fbAQjvLVCAxWsfCA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000790, 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, Nov 19, 2024 at 6:53=E2=80=AFPM Theodore Ts'o wrote= : > > On Tue, Nov 19, 2024 at 10:45:52AM +0100, Mateusz Guzik wrote: > > > > On my v1 Jan remarked 1.5% is not a particularly high win questioning > > whether doing this makes sense. I noted the value is only this small > > because of other slowdowns. > > Do you have a workload in mind which calls readlink() at sufficiently > high numbers such that this would be noticeable in > non-micro-benchmarks? What motiviated you to do this work? > I'm just messing about here. Given the triviality of the patch I'm not sure where the objection is coming from. I can point a finger at changes made by other people for supposed perf gains which are virtually guaranteed to be invisible in isolation, just like this one. Anyhow, I landed here from strlen -- the sucker is operating one byte at a time which I was looking to sort out, but then I noticed that one of the more commonly executing consumers does not even need to call it. --=20 Mateusz Guzik