varnishcache
Disable Transparent Hugepage
🤔
I am aware of the problem, but is this not a specific jemalloc+THP issue which surfaces exclusively with the malloc storage? For cases where the malloc storage is not used, disabling THP might be counter-productive (after all, there is a good reason for introducing it to reduce TLB misses), so if this was otherwise found to be a useful addition, I would ask to at least make it a jail flag, possibly on by default, but possible to disable.
(oh, and also, are these really "stability" issues? All I am aware of is memory usage going overboard)
I cherry-picked the first commit to master because it improves documentation for the release.
Varnish used to crash left and right when Transparent Hugepage first landed, and we sometime still see inexplicable problems go away once we disable the feature.
I'm fine with the addition of a jail option to control this, would you agree to disabled by default?
As a matter of principle, I'll be +0 on how linux_jail works and what it does.
bugwash: @cartoush please make this a jail option. disabled by default is preferred, enabled by default would also work for me, as long as there is admin control at all
FTR: I ended up editing this change quite heavily. See the commit message for details.