On Fri, 11 May 2012, Minchan Kim wrote: > On 05/11/2012 05:30 PM, Sasha Levin wrote: > > >> Commit 93278814d359 "mm: fix division by 0 in percpu_pagelist_fraction()" > >> mistakenly initialized percpu_pagelist_fraction to the sysctl's minimum 8, > >> which leaves 1/8th of memory on percpu lists (on each cpu??); but most of > >> us expect it to be left unset at 0 (and it's not then used as a divisor). > > > > I'm a bit confused about this, does it mean that once you set > > percpu_pagelist_fraction to a value above the minimum, you can no > > longer set it back to being 0? > > > Unfortunately, Yes. :( > It's rather awkward and need fix. It's inelegant, but does that actually need a fix? Has anybody asked for that option in the six years of percpu_pagelist_fraction? Does setting percpu_pagelist_fraction to some large number perhaps approximate to the default behaviour of percpu_pagelist_fraction 0? I don't care very much either way - just don't want this discussion to divert from applying last night's fix to the default behaviour that most people expect. Hugh -- 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>