On Tue, 2010-08-17 at 12:45 -0400, Dave Jones wrote: > On Tue, Aug 17, 2010 at 12:41:48PM -0400, Eric Paris wrote: > > On Thu, 2010-08-12 at 12:01 -0500, Rex Dieter wrote: > > > kde packagers received a request to consider shipping systems with a > > > higher (default) value of > > > /proc/sys/fs/inotify/max_user_watches > > > to allow for a better experience for noticing changes (notably when > > > using nepomuk indexing of content in users' homedir). > > > > > > The suggested value was something like 524288 (seems the default on f13 > > > is 8192). > > > > > > A recent kde-sig meeting discussed the topic, > > > http://fedoraproject.org/wiki/SIGs/KDE/Meetings/2010-07-27 > > > > > > where mjg59 also agreed "It's probably justifiable to increase it". > > > > > > So, any comments or objections implementing this (for f14)? > > > > I'm not opposed to it but this does allow used to allocate and hold > > kernel memory. The math is roughly 200 bytes per watch. So right now a > > normal user can only allocate about 200*8192 bytes which is about 1.6M > > of kernel memory. Not such a bad thing. > > > > Your suggestion would allow the user to allocate 200 * 524288 = 105M. > > On a 64bit system this might not matter, but on a 32bit system this is a > > substantial amount of the memory the kernel has. > > > > And these allocations are not counted against normal userspace limits. > > > > I'm not opposed to upping it, especially on x86_64, but maybe not quite > > that high.... > > ideally, when an application that cares about this is installed, it could > increase it via sysctl.conf > That default isn't a one size fits all. Regardless of what we set it to, > someone is going to want it smaller/bigger. I think we want to be very careful how much we suggest $random-package muck with sysctl. Ubuntu got a black eye since wine automatically changed mmap_min_addr if it was installed. It's not always clear what the implications of a change include. How many people on this list (the kernel list) would have guessed that the suggestion here would allow 5-10 users completely DoS a 32 machine? Rex, if you do decide to change it in sysctl lets try to keep it within a factor of 10 or so? You might want to ask the upstream kernel community what they think. -Eric _______________________________________________ kernel mailing list kernel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/kernel
