On Wed, 7 May 2014 11:12:58 +0200 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Tue, May 06, 2014 at 04:28:56PM -0700, Andrew Morton wrote: > > On Wed, 7 May 2014 02:03:23 +0300 "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> wrote: > > > > > remap_file_pages(2) was invented to be able efficiently map parts of > > > huge file into limited 32-bit virtual address space such as in database > > > workloads. > > > > > > Nonlinear mappings are pain to support and it seems there's no > > > legitimate use-cases nowadays since 64-bit systems are widely available. > > > > > > Let's deprecate remap_file_pages() syscall in hope to get rid of code > > > one day. > > > > Before we do this we should ensure that your proposed replacement is viable > > and desirable. If we later decide not to proceed with it, this patch will > > sow confusion. > > Chicken meet Egg ? > > How are we supposed to test if its viable if we have no known users? Same way we always do - finish the code, developer test, review, give it a spin in linux-next, etc. Do some microbenchmarking to get an understanding of the impact on people who are using r_f_p for real. The current patchset looks rather alphaish. > The > printk() might maybe (hopefully) get us some reaction in say a years > time, much longer if we're really unlucky. > > That said, we could make the syscall return -ENOSYS unless a sysctl was > touched. The printk() would indeed have to mention said sysctl and a > place to find information about why we're doing this.. > > But by creating more pain (people have to actually set the sysctl, and > we'll have to universally agree to inflict pain on distro people that > set it by default -- say, starve them from beer at the next conf.) we're > more likely to get an answer sooner. Could be. We should consult distro people, Oracle people... -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>