| > The membarrier syscall can fail to allocate, returning ENOMEM. This is mentioned in the source comment, but not documented in the membarrier(2) manual page. https://elixir.bootlin.com/linux/v7.1.2/source/kernel/sched/... In reality... what is it allocating? https://elixir.bootlin.com/linux/v7.1.2/source/kernel/sched/... Ok, so it needs to allocate a cpumask (tiny) under some usages. Similar requirement in other sites, e.g.: https://elixir.bootlin.com/linux/v7.1.2/source/kernel/sched/... Depending on kernel config (e.g., !CONFIG_CPUMAKS_OFFSTACK), this allocation literally cannot fail: https://elixir.bootlin.com/linux/v7.1.2/source/include/linux... On OFFSTACK configs, it's merely a tiny heap allocation: https://elixir.bootlin.com/linux/v7.1.2/source/lib/cpumask.c... If this fails, your system is already hosed; program abort vs kernel lock up a few seconds later is probably immaterial. I think folly's choice to abort is a reasonable one. |