From: Alexander Duyck <alexander.duyck@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: virtio-dev@lists.oasis-open.org, kvm list <kvm@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
David Hildenbrand <david@redhat.com>,
Dave Hansen <dave.hansen@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Matthew Wilcox <willy@infradead.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
will@kernel.org, linux-arm-kernel@lists.infradead.org,
Oscar Salvador <osalvador@suse.de>,
Yang Zhang <yang.zhang.wz@gmail.com>,
Pankaj Gupta <pagupta@redhat.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Nitesh Narayan Lal <nitesh@redhat.com>,
Rik van Riel <riel@surriel.com>,
lcapitulino@redhat.com, "Wang, Wei W" <wei.w.wang@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
ying.huang@intel.com, Paolo Bonzini <pbonzini@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v9 2/8] mm: Adjust shuffle code to allow for future coalescing
Date: Tue, 10 Sep 2019 07:48:41 -0700 [thread overview]
Message-ID: <CAKgT0Ufw1h45q9H5jraOJkRwvnrxfVNe99bVF1VWCLrzxCrMmg@mail.gmail.com> (raw)
In-Reply-To: <20190910122030.GV2063@dhcp22.suse.cz>
On Tue, Sep 10, 2019 at 5:20 AM Michal Hocko <mhocko@kernel.org> wrote:
>
> On Sat 07-09-19 10:25:20, Alexander Duyck wrote:
> > From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> >
> > Move the head/tail adding logic out of the shuffle code and into the
> > __free_one_page function since ultimately that is where it is really
> > needed anyway. By doing this we should be able to reduce the overhead
> > and can consolidate all of the list addition bits in one spot.
>
> This changelog doesn't really explain why we want this. You are
> reshuffling the code, allright, but why do we want to reshuffle? Is the
> result readability a better code reuse or something else? Where
> does the claimed reduced overhead coming from?
>
> From a quick look buddy_merge_likely looks nicer than the code splat
> we have. Good.
>
> But then
>
> > Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>
> [...]
>
> > - if (is_shuffle_order(order))
> > - add_to_free_area_random(page, &zone->free_area[order],
> > - migratetype);
> > + area = &zone->free_area[order];
> > + if (is_shuffle_order(order) ? shuffle_pick_tail() :
> > + buddy_merge_likely(pfn, buddy_pfn, page, order))
>
> Ouch this is just awful don't you think?
Yeah. I am going to go with Kirill's suggestion and probably do
something more along the lines of:
bool to_tail;
...
if (is_shuffle_order(order))
to_tail = shuffle_pick_tail();
else
to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);
if (to_tail)
add_to_free_area_tail(page, area, migratetype);
else
add_to_free_area(page, area, migratetype);
next prev parent reply other threads:[~2019-09-10 14:48 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
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 [this message]
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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