On Fri, Oct 03, 2014 at 02:22:20PM -0400, Benjamin LaHaise wrote: > On Fri, Oct 03, 2014 at 12:13:39PM -0600, Jens Axboe wrote: > > How are applications supposed to deal with ENOMEM? I think the answer > > here is that they can't, it would be a fatal condition. AIO must provide > > isn't own guarantee of progress, with a mempool or similar. > > I'm not sure if using a mempool is appropriate for allocations that are > driven by userland code. At least with an ENOMEM error, an application > could free up some of the memory it allocated and possibly recover the > system.
I guess it's going to depend on the application... some applications really want to always make forward progress (much like a lot of code in the kernel), so they're going to want the mempool semantics and we in the kernel are in a much better position to implement that correctly (think of all the applications that are just going to sleep and retry on -ENOMEM). we kind of want another flag in the syscall args that's the moral equivalent of MSG_DONTWAIT but for memory allocations; it'd translate into "mempool + GFP_KERNEL, or GFP_NOWAIT". not that I'm actually going to implement that :) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
