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Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: RFC: system-wide default tunables Content-Language: en-US To: DJ Delorie Cc: adhemerval.zanella@linaro.org, libc-alpha@sourceware.org References: From: Siddhesh Poyarekar In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-3031.4 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 2023-10-17 12:45, DJ Delorie wrote: > Siddhesh Poyarekar writes: >> Only stricter overrides to systemwide tunables should be allowed, > > This leads to the next question: how to express these constraints in the > tunables.conf file. A the simplest, prefixing each tunable with '+', > '-', or '=' for example? For stricter, looser, or can't change? Else > we need to come up with some more flexible "flag parser". > Actually I wasn't thinking of any conf file related constraint markup, I was thinking of TUNABLE_CALLBACKs encoding constraints in whichever way they deem fit. e.g. for ibt it could be: void TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *valp) { if (!strcmp (valp->system_default, "always_on")) return; /* Otherwise read the value. */ }