On Wed, Oct 25, 2017 at 11:23:01AM +0200, Paolo Bonzini wrote:
> On 25/10/2017 10:40, Andrew Jones wrote:
> > On Tue, Oct 24, 2017 at 05:21:43PM +0200, Paolo Bonzini wrote:
> >> vmalloc is not able to provide allocations with alignment greater than
> >> PAGE_SIZE, so avoid them.
> >>
> >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> >> ---
> >> lib/arm/asm/thread_info.h | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/lib/arm/asm/thread_info.h b/lib/arm/asm/thread_info.h
> >> index 9f0c14d..c2ecebb 100644
> >> --- a/lib/arm/asm/thread_info.h
> >> +++ b/lib/arm/asm/thread_info.h
> >> @@ -38,7 +38,7 @@
> >>
> >> static inline void *thread_stack_alloc(void)
> >> {
> >> - void *sp = memalign(THREAD_SIZE, THREAD_SIZE);
> >> + void *sp = memalign(PAGE_SIZE, THREAD_SIZE);
> >> return sp + THREAD_START_SP;
> >> }
> >>
> >
> > This reduces all the secondary cpu's stacks on arm from 16K to 4K.
> > Also, THREAD_SIZE is page aligned, so I'm wondering what's breaking
> > here?
>
> No, they stay 16K but only page-aligned; the prototype is
>
> void *memalign(size_t alignment, size_t size)
>
> vmalloc is not able to satisfy memalign with alignment greater than a
> page size, but the memory blocks can be as large as you want.
Argh, sorry for the noise. I was obviously still asleep and lazy when
I skimmed the series this morning...
Thanks,
drew
