[RFC v2] slab_arena: Enhance slab_arena_create to support madvise hints

Cyrill Gorcunov gorcunov at gmail.com
Mon May 13 14:41:31 MSK 2019


On Mon, May 13, 2019 at 02:21:56PM +0300, Vladimir Davydov wrote:
> On Mon, May 13, 2019 at 01:30:32PM +0300, Cyrill Gorcunov wrote:
> > > > +check_symbol_exists(MADV_NORMAL sys/mman.h TARANTOOL_SMALL_HAS_MADV_NORMAL)
> > > > +check_symbol_exists(MADV_DONTDUMP sys/mman.h TARANTOOL_SMALL_HAS_MADV_DONTDUMP)
> > > 
> > > Do we really need to check all of that? Is a check for MADV_DONTDUMP not
> > > enough?
> > 
> > Well, strictly speaking we should check each definition we use, because I'm
> > not sure if MADV_NORMAL defined on other than linux environments.
> 
> Why do we use MADV_NORMAL, anyway? We only need MADV_DONTDUMP or
> am I missing something?

Because we need a default value, which would be different
from MADV_DONTDUMP. Actually MADV_NORMAL = 0 in linux and
I think we may even live without this member initialized
but for code readability sake I assign mode to MADV_NORMAL
by default.



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