Nick Piggin <npiggin@xxxxxxx> writes: >> In addition for a complete solution we need: >> - A reliable way the file structures that we need to revoke. >> - To wait for but not tamper with ongoing file creation and cleanup. >> - A guarantee that all with user space controlled duration are removed. >> >> The file_hotplug_lock has a very unique implementation necessitated by >> the need to have no performance impact on existing code. Classic locking > > Well, it isn't no performance impact. Function calls, branches, icache > and dcache... Practically none. Everything I could measure was in the noise. It is cheaper than any serializing locking primitive. I ran both lmbench and did some microbenchmark testing. So I know on the fast path the overhead is minimal. Certainly less than what we are doing in sysfs and proc today. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
