Messages in this thread | | | Subject | Re: [PATCH 1/2] mm: Keep int fields in struct shrink_control together | From | Kirill Tkhai <> | Date | Thu, 19 Jul 2018 14:14:58 +0300 |
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On 19.07.2018 14:10, Michal Hocko wrote: > On Thu 19-07-18 13:51:19, Kirill Tkhai wrote: >> gfp_t is of unsigned type, so let's move nid to keep >> them together. > > I guess you meant unsigned int so you can fill up a hole in > shrink_control and as such reduce the stack consumption a bit (at least > on 64b).
Yes, I mean unsigned as synonym of unsigned int and this is the reason :)
> An output from pahole is usually a great tool to visualize this. > > die__process_function: tag not supported (INVALID)! > struct shrink_control { > gfp_t gfp_mask; /* 0 4 */ > > /* XXX 4 bytes hole, try to pack */ > > long unsigned int nr_to_scan; /* 8 8 */ > long unsigned int nr_scanned; /* 16 8 */ > int nid; /* 24 4 */ > > /* XXX 4 bytes hole, try to pack */ > > struct mem_cgroup * memcg; /* 32 8 */ > > /* size: 40, cachelines: 1, members: 5 */ > /* sum members: 32, holes: 2, sum holes: 8 */ > /* last cacheline: 40 bytes */ > }; >>> >> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> > > Acked-by: Michal Hocko <mhocko@suse.com> > >> --- >> include/linux/shrinker.h | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h >> index b154fd2b084c..d58aaaed34a4 100644 >> --- a/include/linux/shrinker.h >> +++ b/include/linux/shrinker.h >> @@ -12,6 +12,9 @@ >> struct shrink_control { >> gfp_t gfp_mask; >> >> + /* current node being shrunk (for NUMA aware shrinkers) */ >> + int nid; >> + >> /* >> * How many objects scan_objects should scan and try to reclaim. >> * This is reset before every call, so it is safe for callees >> @@ -26,9 +29,6 @@ struct shrink_control { >> */ >> unsigned long nr_scanned; >> >> - /* current node being shrunk (for NUMA aware shrinkers) */ >> - int nid; >> - >> /* current memcg being shrunk (for memcg aware shrinkers) */ >> struct mem_cgroup *memcg; >> }; >
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