Heinrich Schuchardt <xypron.g...@gmx.de> writes: > Did this patch when applied to the customer's kernel solve any problem? > > WebSphere MQ is a messaging application. If it hits the current limits > of threads-max, there is a bug in the software or in the way that it has > been set up at the customer. Instead of messing around with the kernel > the application should be fixed.
While it is true that almost every workload will be buggy if it exceeds 1/8 of memory with just the kernel data structures for threads. It is not necessary true of every application. I can easily imagine cases up around 1/2 of memory where things could work reasonably. Further we can exhaust all of memory much more simply in a default configuration by malloc'ing more memory that in physically present and zeroing it all. Henrich, you were the one messed with the kernel by breaking a reasonable kernel tunable. AKA you caused a regression. That violates the no regression rule. As much as possible we fix regressions so software that used to work continues to work. Removing footguns is not a reason to introduce a regression. I do agree that Michal's customer's problem sounds like it is something else but if the kernel did not have a regression we could focus on the real problem instead of being side tracked by the regression. > With this patch you allow administrators to set values that will crash > their system. And they will not even have a way to find out the limits > which he should adhere to. So expect a lot of systems to be downed > this way. Nope. The system administrator just setting a higher value whon't crash their system. Only using that many resources would crash the system. Nor is a sysctl like this for discovering the physical limits of a machine. Which the current value is vastly inappropriate for. As the physical limits of many machines are much higher than 1/8 of memory. Eric
