On Mon, 26 Sep 2011 13:29:45 +0200 Johannes Weiner <jweiner@xxxxxxxxxx> wrote: > On Sun, Sep 25, 2011 at 04:29:40PM +0530, Kautuk Consul wrote: > > write_scan_unavictable_node checks the value req returned by > > strict_strtoul and returns 1 if req is 0. > > > > However, when strict_strtoul returns 0, it means successful conversion > > of buf to unsigned long. > > > > Due to this, the function was not proceeding to scan the zones for > > unevictable pages even though we write a valid value to the > > scan_unevictable_pages sys file. > > Given that there is not a real reason for this knob (anymore) and that > it apparently never really worked since the day it was introduced, how > about we just drop all that code instead? > Yes, let's remove it if at all possible. However, to be nice to people I do think we should emit a once-per-boot printk when someone tries to use it, then remove it for real at least a couple of kernel cycles later. Just in case someone's script or tuning app is trying to open that procfs file. > > --- > From: Johannes Weiner <jweiner@xxxxxxxxxx> > Subject: mm: remove sysctl to manually rescue unevictable pages > > At one point, anonymous pages were supposed to go on the unevictable > list when no swap space was configured, and the idea was to manually > rescue those pages after adding swap and making them evictable again. > But nowadays, swap-backed pages on the anon LRU list are not scanned > without available swap space anyway, so there is no point in moving > them to a separate list anymore. > > The manual rescue could also be used in case pages were stranded on > the unevictable list due to race conditions. But the code has been > around for a while now and newly discovered bugs should be properly > reported and dealt with instead of relying on such a manual fixup. > > Signed-off-by: Johannes Weiner <jweiner@xxxxxxxxxx> The changelog failed to note that the sysctl doesn't actually *work*. This is a pretty strong argument for removing it ;) Also, a reported-by:Kautuk would have been nice. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>