Hi Michal, On Tue, 3 May 2011, Michal Hocko wrote: > Hi Andrew, > the patch bellow probably got lost in the huge "parisc crashes with slub" > thread triggered by my earlier clean up in this area so I am resending > it standalone. > --- > From 2e79c7e73a39a09389a84a8f37eb2a2f2f2859f5 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@xxxxxxx> > Date: Tue, 19 Apr 2011 11:11:41 +0200 > Subject: [PATCH] mm: get rid of CONFIG_STACK_GROWSUP || CONFIG_IA64 > > IA64 needs some trickery for Register Backing Store so we have to > export expand_stack_upwards for it even though the architecture expands > its stack downwards normally. > We have defined VM_GROWSUP which is defined only for the above > configuration so let's use it everywhere rather than hardcoded > CONFIG_STACK_GROWSUP || CONFIG_IA64 > > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> Sorry to be negative, but this seems more clever than helpful to me: it does not optimize anything (apart from saving a few bytes in mm/mmap.c itself), obscures the special IA64 case, and relies upon the ways in which we happen to define VM_GROWSUP elsewhere. Not a nack: others may well disagree with me. And, though I didn't find time to comment on your later "symmetrical" patch before it went into mmotm, I didn't see how renaming expand_downwards and expand_upwards to expand_stack_downwards and expand_stack_upwards was helpful either - needless change, and you end up using expand_stack_upwards on something which is not (what we usually call) the stack. Now, if you're looking to make a nice cleanup, how about getting rid of find_vma_prev(), which Linus made redundant when he suddenly added vm_prev in 2.6.36? There's at least one place where I apologize for its expense in a BUG_ON, I'd be glad to see that killed off. Hey, but it's certainly not for me to assign work to you! Hugh > --- > mm/mmap.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index 29c68b0..3ff9edf 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1726,7 +1726,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns > return 0; > } > > -#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) > +#if VM_GROWSUP > /* > * PA-RISC uses this for its stack; IA64 for its Register Backing Store. > * vma is the last one with address > vma->vm_end. Have to extend vma. > @@ -1777,7 +1777,7 @@ int expand_stack_upwards(struct vm_area_struct *vma, unsigned long address) > khugepaged_enter_vma_merge(vma); > return error; > } > -#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ > +#endif /* VM_GROWSUP */ > > /* > * vma is the first one with address < vma->vm_start. Have to extend vma. > -- > 1.7.4.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>