I am well familiar with flash and kernel and swapping. I am unfamiliar with android kernel patches and userspace, hence the question. the device has a hard-disk, so wear is not an issue. I mount swap in android's init in the ramdisk and it indeed is enabled (as seen by runnig top on serial console)
---- Best Regards On Mon, Sep 6, 2010 at 2:38 PM, Brad Davis <bda...@cove-mtn.com> wrote: > You also need to bind swap to disk partitions and/or files (I can't > help you here as I don't do this on Linux kernels with fancy > bootloaders...). > > Again, don't do this on flash unless you are ready to replace the > flash often. Swap heavily writes (if you have the memory to cache the > swap, then don't swap) the disk, which is extremely slow on flash and > the flash will break after a relatively small number of writes. > > I can't tell you much about the swap subsystem on Linux, but it is > possible that swapping to a flash partition will bypass the code that > handles bad flash blocks. > > Swapping to a flash file may double the actual number of writes > (because of the interaction between writing single blocks in the file > and the way flash file systems work), killing the flash faster. > > Has Android been tested with swapping? Probably not, it is an > embedded system, not a general purpose OS (I know I wouldn't expend > any resources testing it). It may work, but then again, the Google > additions to the standard kernel may prevent swapping from working > properly (after all, swapping is turned off for kernel development and > testing). Did the kernel engineers plan to disable swapping?, > probably not, but kernels are complex masses of code and things > happen. > > I just checked my Ubuntu desktop. It is using 1gig of memory (no swap > because my machine has 3gig) of which about 45meg is the X server and > another 66+meg is Gnome. A full Unbuntu desktop would thrash 16meg to > death... (Firefox alone uses almost 200meg of virtual memory.) (I > have actually used X/Motif on 16meg machines and we didn't get to have > all the eye-candy that people now expect.) > > That said, if you have a hard disk installed or you swap over the > network, you need to understand and modify the Android partitions > (which were set up for flash) and possibly the mount code in init.rc. > It probably isn't hard, but I doubt that many people are doing this > (Android is a battery OS and dependencies on networks and disks don't > work well on batteries). > > So, if you don't understand swapping and don't understand flash/flash > file systems, you are probably going to have to learn a bunch. You > have probably alone in your endeavors as the rest of the Android > community isn't going to swap (I can tell you what it takes to > support a 5:5:5 screen). > > Good Luck. > > On Sep 5, 7:11 pm, Dmitry Grinberg <dmitr...@gmail.com> wrote: > > My kernel has swap enabled. > > > > ---- > > Best Regards > > > > On Sun, Sep 5, 2010 at 4:34 PM, Brad Davis <bda...@cove-mtn.com> wrote: > > > I don't think the standard Android kernel has swap enabled and/or > > > configured (and you don't want to swap to flash as you will quickly > > > kill the flash). > > > > > And yes, I've watched memory usage as Android boots and you need 64mb. > > > > > -- > > > unsubscribe: > > > android-porting+unsubscr...@googlegroups.com<android-porting%2bunsubscr...@googlegroups.com> > <android-porting%2bunsubscr...@googlegroups.com<android-porting%252bunsubscr...@googlegroups.com> > > > > > website:http://groups.google.com/group/android-porting > > -- > unsubscribe: > android-porting+unsubscr...@googlegroups.com<android-porting%2bunsubscr...@googlegroups.com> > website: http://groups.google.com/group/android-porting > -- unsubscribe: android-porting+unsubscr...@googlegroups.com website: http://groups.google.com/group/android-porting
