From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>,
virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org,
mst@redhat.com, catalin.marinas@arm.com, david@redhat.com,
dave.hansen@intel.com, linux-kernel@vger.kernel.org,
willy@infradead.org, mhocko@kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, will@kernel.org,
linux-arm-kernel@lists.infradead.org, osalvador@suse.de,
yang.zhang.wz@gmail.com, pagupta@redhat.com,
konrad.wilk@oracle.com, nitesh@redhat.com, riel@surriel.com,
lcapitulino@redhat.com, wei.w.wang@intel.com,
aarcange@redhat.com, ying.huang@intel.com, pbonzini@redhat.com,
dan.j.williams@intel.com, fengguang.wu@intel.com,
kirill.shutemov@linux.intel.com
Subject: Re: [PATCH v9 2/8] mm: Adjust shuffle code to allow for future coalescing
Date: Mon, 9 Sep 2019 18:35:29 +0300 [thread overview]
Message-ID: <20190909153529.3crs74uraos27ffh@box> (raw)
In-Reply-To: <22a896255cba877cf820f552667e1bc14268fa20.camel@linux.intel.com>
On Mon, Sep 09, 2019 at 08:22:11AM -0700, Alexander Duyck wrote:
> > > + area = &zone->free_area[order];
> > > + if (is_shuffle_order(order) ? shuffle_pick_tail() :
> > > + buddy_merge_likely(pfn, buddy_pfn, page, order))
> >
> > Too loaded condition to my taste. Maybe
> >
> > bool to_tail;
> > ...
> > if (is_shuffle_order(order))
> > to_tail = shuffle_pick_tail();
> > else if (buddy_merge_likely(pfn, buddy_pfn, page, order))
> > to_tail = true;
> > else
> > to_tail = false;
>
> I can do that, although I would tweak this slightly and do something more
> like:
> if (is_shuffle_order(order))
> to_tail = shuffle_pick_tail();
> else
> to_tail = buddy+_merge_likely(pfn, buddy_pfn, page, order);
Okay. Looks fine.
> > if (to_tail)
> > add_to_free_area_tail(page, area, migratetype);
> > else
> > add_to_free_area(page, area, migratetype);
> >
> > > + add_to_free_area_tail(page, area, migratetype);
> > > else
> > > - add_to_free_area(page, &zone->free_area[order], migratetype);
> > > -
> > > + add_to_free_area(page, area, migratetype);
> > > }
> > >
> > > /*
> > > diff --git a/mm/shuffle.c b/mm/shuffle.c
> > > index 9ba542ecf335..345cb4347455 100644
> > > --- a/mm/shuffle.c
> > > +++ b/mm/shuffle.c
> > > @@ -4,7 +4,6 @@
> > > #include <linux/mm.h>
> > > #include <linux/init.h>
> > > #include <linux/mmzone.h>
> > > -#include <linux/random.h>
> > > #include <linux/moduleparam.h>
> > > #include "internal.h"
> > > #include "shuffle.h"
> >
> > Why do you move #include <linux/random.h> from .c to .h?
> > It's not obvious to me.
>
> Because I had originally put the shuffle logic in an inline function. I
> can undo that now as I when back to doing the randomness in the .c
> sometime v5 I believe.
Yes, please. It's needless change now.
>
> > > @@ -190,8 +189,7 @@ struct batched_bit_entropy {
> > >
> > > static DEFINE_PER_CPU(struct batched_bit_entropy, batched_entropy_bool);
> > >
> > > -void add_to_free_area_random(struct page *page, struct free_area *area,
> > > - int migratetype)
> > > +bool __shuffle_pick_tail(void)
> > > {
> > > struct batched_bit_entropy *batch;
> > > unsigned long entropy;
> > > @@ -213,8 +211,5 @@ void add_to_free_area_random(struct page *page, struct free_area *area,
> > > batch->position = position;
> > > entropy = batch->entropy_bool;
> > >
> > > - if (1ul & (entropy >> position))
> > > - add_to_free_area(page, area, migratetype);
> > > - else
> > > - add_to_free_area_tail(page, area, migratetype);
> > > + return 1ul & (entropy >> position);
> > > }
> > > diff --git a/mm/shuffle.h b/mm/shuffle.h
> > > index 777a257a0d2f..0723eb97f22f 100644
> > > --- a/mm/shuffle.h
> > > +++ b/mm/shuffle.h
> > > @@ -3,6 +3,7 @@
> > > #ifndef _MM_SHUFFLE_H
> > > #define _MM_SHUFFLE_H
> > > #include <linux/jump_label.h>
> > > +#include <linux/random.h>
> > >
> > > /*
> > > * SHUFFLE_ENABLE is called from the command line enabling path, or by
> > > @@ -22,6 +23,7 @@ enum mm_shuffle_ctl {
> > > DECLARE_STATIC_KEY_FALSE(page_alloc_shuffle_key);
> > > extern void page_alloc_shuffle(enum mm_shuffle_ctl ctl);
> > > extern void __shuffle_free_memory(pg_data_t *pgdat);
> > > +extern bool __shuffle_pick_tail(void);
> > > static inline void shuffle_free_memory(pg_data_t *pgdat)
> > > {
> > > if (!static_branch_unlikely(&page_alloc_shuffle_key))
> > > @@ -43,6 +45,11 @@ static inline bool is_shuffle_order(int order)
> > > return false;
> > > return order >= SHUFFLE_ORDER;
> > > }
> > > +
> > > +static inline bool shuffle_pick_tail(void)
> > > +{
> > > + return __shuffle_pick_tail();
> > > +}
> >
> > I don't see a reason in __shuffle_pick_tail() existing if you call it
> > unconditionally.
>
> That is for compilation purposes. The function is not used in the
> shuffle_pick_tail below that always returns false.
Wouldn't it be the same if you rename __shuffle_pick_tail() to
shuffle_pick_tail() and put its declaration under the same #ifdef?
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-09-09 15:35 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-07 17:25 [PATCH v9 0/8] stg mail -e --version=v9 \ Alexander Duyck
2019-09-07 17:25 ` [PATCH v9 1/8] mm: Add per-cpu logic to page shuffling Alexander Duyck
2019-09-09 8:14 ` David Hildenbrand
2019-09-09 15:11 ` Alexander Duyck
2019-09-10 12:11 ` Michal Hocko
2019-09-10 22:14 ` Alexander Duyck
2019-09-10 22:11 ` Alexander Duyck
2019-09-09 9:07 ` Kirill A. Shutemov
2019-09-09 15:12 ` Alexander Duyck
2019-09-07 17:25 ` [PATCH v9 2/8] mm: Adjust shuffle code to allow for future coalescing Alexander Duyck
2019-09-09 8:19 ` David Hildenbrand
2019-09-09 9:47 ` Kirill A. Shutemov
2019-09-09 15:22 ` Alexander Duyck
2019-09-09 15:35 ` Kirill A. Shutemov [this message]
2019-09-09 15:37 ` Alexander Duyck
2019-09-09 16:43 ` Alexander Duyck
2019-09-09 17:00 ` Kirill A. Shutemov
2019-09-10 12:20 ` Michal Hocko
2019-09-10 14:48 ` Alexander Duyck
2019-09-07 17:25 ` [PATCH v9 3/8] mm: Move set/get_pcppage_migratetype to mmzone.h Alexander Duyck
2019-09-09 8:22 ` David Hildenbrand
2019-09-09 9:56 ` Kirill A. Shutemov
2019-09-09 18:01 ` Alexander Duyck
2019-09-09 18:12 ` Alexander Duyck
2019-09-10 12:23 ` Michal Hocko
2019-09-10 14:46 ` Alexander Duyck
2019-09-10 17:45 ` Michal Hocko
2019-09-10 20:26 ` Alexander Duyck
2019-09-07 17:25 ` [PATCH v9 4/8] mm: Use zone and order instead of free area in free_list manipulators Alexander Duyck
2019-09-10 12:27 ` Michal Hocko
2019-09-07 17:25 ` [PATCH v9 5/8] arm64: Move hugetlb related definitions out of pgtable.h to page-defs.h Alexander Duyck
2019-09-09 8:52 ` David Hildenbrand
2019-09-09 15:27 ` Alexander Duyck
2019-09-17 17:48 ` Will Deacon
2019-09-17 20:07 ` Alexander Duyck
2019-09-07 17:25 ` [PATCH v9 6/8] mm: Introduce Reported pages Alexander Duyck
2019-09-09 14:42 ` Kirill A. Shutemov
2019-09-09 16:25 ` Alexander Duyck
2019-09-09 16:33 ` Kirill A. Shutemov
2019-09-07 17:26 ` [PATCH v9 7/8] virtio-balloon: Pull page poisoning config out of free page hinting Alexander Duyck
2019-09-09 8:59 ` David Hildenbrand
2019-09-09 15:31 ` Alexander Duyck
2019-09-07 17:26 ` [PATCH v9 8/8] virtio-balloon: Add support for providing unused page reports to host Alexander Duyck
2019-09-07 17:34 ` [PATCH v9 0/8] mm / virtio: Provide support for unused page reporting Alexander Duyck
2019-09-10 12:42 ` [PATCH v9 0/8] stg mail -e --version=v9 \ Michal Hocko
2019-09-10 14:42 ` Alexander Duyck
2019-09-10 14:47 ` Michal Hocko
2019-09-10 16:05 ` Alexander Duyck
2019-09-10 16:18 ` [virtio-dev] " Dr. David Alan Gilbert
2019-09-10 16:22 ` David Hildenbrand
2019-09-11 9:23 ` Michael S. Tsirkin
2019-09-11 9:50 ` David Hildenbrand
2019-09-10 17:52 ` Michal Hocko
2019-09-10 18:00 ` Michal Hocko
2019-09-10 20:37 ` Alexander Duyck
2019-09-10 21:23 ` Alexander Duyck
2019-09-11 11:36 ` Michal Hocko
2019-09-11 11:47 ` David Hildenbrand
2019-09-11 12:08 ` Michael S. Tsirkin
2019-09-11 12:19 ` Michal Hocko
2019-09-11 12:25 ` Michal Hocko
2019-09-11 12:42 ` David Hildenbrand
2019-09-11 12:54 ` Michal Hocko
2019-09-11 13:03 ` David Hildenbrand
2019-09-11 13:20 ` Michal Hocko
2019-09-11 13:51 ` Michal Hocko
2019-09-11 16:09 ` David Hildenbrand
2019-09-12 7:16 ` Michal Hocko
2019-09-12 7:47 ` David Hildenbrand
2019-09-12 9:26 ` Michal Hocko
2019-09-12 12:00 ` Nitesh Narayan Lal
2019-09-11 14:03 ` Nitesh Narayan Lal
2019-09-11 16:02 ` David Hildenbrand
2019-09-11 13:19 ` Nitesh Narayan Lal
2019-09-11 12:55 ` Nitesh Narayan Lal
2019-09-11 15:12 ` Alexander Duyck
2019-09-12 9:19 ` Michal Hocko
2019-09-12 10:24 ` Kirill A. Shutemov
2019-09-12 11:11 ` Michal Hocko
2019-09-12 15:42 ` Alexander Duyck
2019-09-12 16:35 ` Mel Gorman
2019-09-12 17:48 ` Alexander Duyck
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