Hi All, On Monday, June 22, 2020 3:50:42 PM CEST Rafael J. Wysocki wrote: > Hi All, > > This series is to address the problem with RCU synchronization occurring, > possibly relatively often, inside of acpi_ex_system_memory_space_handler(), > when the namespace and interpreter mutexes are held. > > Like I said before, I had decided to change the approach used in the previous > iteration of this series and to allow the unmap operations carried out by > acpi_ex_system_memory_space_handler() to be deferred in the first place, > which is done in patches [1-2/4]. In the meantime I realized that calling syncrhonize_rcu_expedited() under the "tables" mutex within ACPICA is not quite a good idea too and that there is no reason for any users of acpi_os_unmap_memory() in the tree to use the "sync" variant of unmapping. So, unless I'm missing something, acpi_os_unmap_memory() can be changed to always defer the final unmapping and the only ACPICA change needed to support that is the addition of the acpi_os_release_unused_mappings() call to get rid of the unused mappings when leaving the interpreter (module the extra call in the debug code for consistency). So patches [1-2/4] have been changed accordingly. > However, it turns out that the "fast-path" mapping is still useful on top of > the above to reduce the number of ioremap-iounmap cycles for the same address > range and so it is introduced by patches [3-4/4]. Patches [3-4/4] still do what they did, but they have been simplified a bit after rebasing on top of the new [1-2/4]. The below information is still valid, but it applies to the v3, of course. > For details, please refer to the patch changelogs. > > The series is available from the git branch at > > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git \ > acpica-osl > > for easier testing. Also the series have been tested locally. Thanks, Rafael
