On Fri, 2014-05-02 at 12:54 +0100, James Hogan wrote: > On 01/05/14 18:50, James Bottomley wrote: > > > >> + > >> +config MAX_STACK_SIZE_MB > >> + int "Maximum user stack size (MB)" > >> + default 80 > >> + range 8 256 if METAG > >> + range 8 2048 > >> + depends on STACK_GROWSUP > >> + help > >> + This is the maximum stack size in Megabytes in the VM layout of user > >> + processes when the stack grows upwards (currently only on parisc and > >> + metag arch). The stack will be located at the highest memory address > >> + minus the given value, unless the RLIMIT_STACK hard limit is changed > >> + to a smaller value in which case that is used. > >> + > >> + A sane initial value is 80 MB. > > > > There's one final issue with this: placement of the stack only really > > matters on 32 bits. We have three expanding memory areas: stack, heap > > and maps. On 64 bits these are placed well separated from each other on > > 64 bits, so an artificial limit like this doesn't matter. > > Does the following fixup diff look reasonable? It forces > MAX_STACK_SIZE_MB to 1024 and hides the Kconfig option for 64BIT, > effectively leaving the behaviour unchanged in that case. > > diff --git a/mm/Kconfig b/mm/Kconfig > index e80075979530..b0307f737bd7 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -583,7 +583,8 @@ config GENERIC_EARLY_IOREMAP > bool > > config MAX_STACK_SIZE_MB > - int "Maximum user stack size (MB)" > + int "Maximum user stack size (MB)" if !64BIT > + default 1024 if 64BIT > default 80 > range 8 256 if METAG > range 8 2048
Yes, I think that's probably correct ... parisc doesn't actually have anything other than a testbed 64 bit userspace, so this is a bit theoretical for us. James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
