On Monday, February 18, 2013 01:25:49 PM Vasilis Liaskovitis wrote: > Hi, > > On Thu, Jan 24, 2013 at 11:56:50PM +0100, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <[email protected]> > > > > Since acpi_bus_trim() cannot fail, change its definition to a void > > function, so that its callers don't check the return value in vain > > and update the callers. > > I have missed a few patchsets/discussions in the last month and wanted to > ask a question related to this: Does the new always-succeed 2-pass > trim_device design guarantee safe memory hot-remove operations?
I doesn't by itself. Nor it really can, because the .remove() callbacks of device drivers are not allowed to fail. > Afaict if memory offline fails now, the device is ejected (_EJ0) anyways > causing a panic. Tested in a VM with linux-next-20130207 and > linux-next-20130218 by doing an SCI-eject request on a hot-plugged dimm. > > Are there more patches in development for safe memory hot-remove? Yes, there are. I sent a patch series yesterday introducing some safety measures (you can disable memory hotplug from user space or disable automatic ejection). There's more to come still. The plan is to introduce offline/online operations for memory modules (in analogy with CPU core online/offline) that can be started by user space and memory eject will only be possible after offline (i.e. when the memory module is known to be not in use). Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
