Looking at kernel memory use (based on 2.6.19 with a fedora config), there's some not that hard ways to gain quite a bit of memory back. Most important is CONFIG_NR_CPUS, right now that is set to 255 for everyone; this value is used for scaling a LOT of things in the kernel, and the sad thing is it's not even possible today to get a 255 core/processor machine (you run out of apic ids well before you get that far). Setting CONFIG_NR_CPUS to 64 (which is still huge, even 16 would be more than 99.99999% of the people who use fedora will ever use) will save user 255 64 saving ---------------------------------------------- irq_desc 2154496 294912 1859584 irq_domain 269312 18432 250880 irq_lists 134656 36864 97792 irq_2_pin 100992 27648 73344 irq_timer_state 67328 18432 48896 msi_desc 67328 18432 48896 per_cpu__kstat 33728 9280 24448 ----------------------------------------------- total 2403839 this alone saves 2.4Mb of memory in *static* buffers! Add a bunch more in smaller buffers and all dynamic kernel allocations and it'll be closer to 3Mb.. Easy gain right there. Another one is __log_buf; this is currently 128Kb. Arguably it's important for debugging to get 128Kb of dmesg info, but I wonder if 64Kb would be enough as well, it's another easy save by setting CONFIG_LOG_BUF_SHIFT to 16. A third one is disabling CPU hotplug. CPU hotplug keeps quite a bit of code in the kernel, that otherwise is boot-time only and gets evicted right after boot..... You could argue the same for PCI hotplug but cardbus is sort of the party spoiler there I suppose. I don't know what Dave will pick for CONFIG_STACK_PROTECTOR_ALL; I would suggest to turn this off (while enabling the normal CONFIG_STACK_PROTECTOR); _ALL doesn't add much if any security while it creates bigger and slower code everywhere. (The difference is that _ALL forces the canary on every function, while the normal setting only forces it for functions with buffers on the stack) -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
