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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@suse.de>,
	"Jin, Zhi" <zhi.jin@intel.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm/page_alloc: Skip non present sections on zone initialization
Date: Fri, 10 Jan 2020 16:45:47 +0300	[thread overview]
Message-ID: <20200110134547.v6ju5dxazknfjdj3@box> (raw)
In-Reply-To: <73437651-822f-fcec-3b96-281fb1064cf8@redhat.com>

On Fri, Jan 10, 2020 at 02:15:26PM +0100, David Hildenbrand wrote:
> On 08.01.20 15:40, Michal Hocko wrote:
> > On Mon 30-12-19 12:38:28, Kirill A. Shutemov wrote:
> >> memmap_init_zone() can be called on the ranges with holes during the
> >> boot. It will skip any non-valid PFNs one-by-one. It works fine as long
> >> as holes are not too big.
> >>
> >> But huge holes in the memory map causes a problem. It takes over 20
> >> seconds to walk 32TiB hole. x86-64 with 5-level paging allows for much
> >> larger holes in the memory map which would practically hang the system.
> >>
> >> Deferred struct page init doesn't help here. It only works on the
> >> present ranges.
> >>
> >> Skipping non-present sections would fix the issue.
> > 
> > Makes sense to me.
> > 
> >> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > 
> > That pfn inc back and forth is quite ugly TBH but whatever.
> 
> Indeed, can we please rewrite the loop to fix that?

Any suggestions?

I don't see an obvious way to not break readablity in another place.

-- 
 Kirill A. Shutemov


  reply	other threads:[~2020-01-10 13:45 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-30  9:38 Kirill A. Shutemov
2019-12-31  1:23 ` Baoquan He
2019-12-31  1:33   ` Baoquan He
2020-01-08 14:40 ` Michal Hocko
2020-01-10 13:15   ` David Hildenbrand
2020-01-10 13:45     ` Kirill A. Shutemov [this message]
2020-01-10 14:34       ` David Hildenbrand
2020-01-10 14:47         ` Kirill A. Shutemov
2020-01-10 14:48           ` David Hildenbrand
2020-01-10 14:54             ` Kirill A. Shutemov
2020-01-10 14:56               ` David Hildenbrand
2020-01-10 17:55                 ` Kirill A. Shutemov
2020-01-10 18:05                   ` David Hildenbrand
2020-01-10 18:22                     ` Kirill A. Shutemov

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