From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: Pasha Tatashin <Pavel.Tatashin@microsoft.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "mhocko@suse.com" <mhocko@suse.com>,
"dave.jiang@intel.com" <dave.jiang@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"willy@infradead.org" <willy@infradead.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"yi.z.zhang@linux.intel.com" <yi.z.zhang@linux.intel.com>,
"khalid.aziz@oracle.com" <khalid.aziz@oracle.com>,
"rppt@linux.vnet.ibm.com" <rppt@linux.vnet.ibm.com>,
"vbabka@suse.cz" <vbabka@suse.cz>,
"sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
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"mgorman@techsingularity.net" <mgorman@techsingularity.net>,
"mingo@kernel.org" <mingo@kernel.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>
Subject: Re: [mm PATCH v4 3/6] mm: Use memblock/zone specific iterator for handling deferred page init
Date: Wed, 31 Oct 2018 09:05:04 -0700 [thread overview]
Message-ID: <a7c1bc0ed1e68cbc32c4dd6753fa9f8ff7f1421f.camel@linux.intel.com> (raw)
In-Reply-To: <5b937f29-a6e1-6622-b035-246229021d3e@microsoft.com>
On Wed, 2018-10-31 at 15:40 +0000, Pasha Tatashin wrote:
>
> On 10/17/18 7:54 PM, Alexander Duyck wrote:
> > This patch introduces a new iterator for_each_free_mem_pfn_range_in_zone.
> >
> > This iterator will take care of making sure a given memory range provided
> > is in fact contained within a zone. It takes are of all the bounds checking
> > we were doing in deferred_grow_zone, and deferred_init_memmap. In addition
> > it should help to speed up the search a bit by iterating until the end of a
> > range is greater than the start of the zone pfn range, and will exit
> > completely if the start is beyond the end of the zone.
> >
> > This patch adds yet another iterator called
> > for_each_free_mem_range_in_zone_from and then uses it to support
> > initializing and freeing pages in groups no larger than MAX_ORDER_NR_PAGES.
> > By doing this we can greatly improve the cache locality of the pages while
> > we do several loops over them in the init and freeing process.
> >
> > We are able to tighten the loops as a result since we only really need the
> > checks for first_init_pfn in our first iteration and after that we can
> > assume that all future values will be greater than this. So I have added a
> > function called deferred_init_mem_pfn_range_in_zone that primes the
> > iterators and if it fails we can just exit.
> >
> > On my x86_64 test system with 384GB of memory per node I saw a reduction in
> > initialization time from 1.85s to 1.38s as a result of this patch.
> >
> > Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>
> Hi Alex,
>
> Could you please split this patch into two parts:
>
> 1. Add deferred_init_maxorder()
> 2. Add memblock iterator?
>
> This would allow a better bisecting in case of problems. Chaning two
> loops into deferred_init_maxorder() while a good idea, is still
> non-trivial and might lead to bugs.
>
> Thank you,
> Pavel
I can do that, but I will need to flip the order. I will add the new
iterator first and then deferred_init_maxorder. Otherwise the
intermediate step ends up being too much throw-away code.
- Alex
next prev parent reply other threads:[~2018-10-31 16:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-17 23:54 [mm PATCH v4 0/6] Deferred page init improvements Alexander Duyck
2018-10-17 23:54 ` [mm PATCH v4 1/6] mm: Use mm_zero_struct_page from SPARC on all 64b architectures Alexander Duyck
2018-10-18 18:29 ` Pavel Tatashin
2018-10-29 20:12 ` Michal Hocko
2018-10-17 23:54 ` [mm PATCH v4 2/6] mm: Drop meminit_pfn_in_nid as it is redundant Alexander Duyck
2018-10-17 23:54 ` [mm PATCH v4 3/6] mm: Use memblock/zone specific iterator for handling deferred page init Alexander Duyck
2018-10-31 15:40 ` Pasha Tatashin
2018-10-31 16:05 ` Alexander Duyck [this message]
2018-10-31 16:06 ` Pasha Tatashin
2018-11-01 6:17 ` Mike Rapoport
2018-11-01 15:10 ` Alexander Duyck
2018-10-17 23:54 ` [mm PATCH v4 4/6] mm: Move hot-plug specific memory init into separate functions and optimize Alexander Duyck
2018-10-17 23:54 ` [mm PATCH v4 5/6] mm: Add reserved flag setting to set_page_links Alexander Duyck
2018-10-17 23:54 ` [mm PATCH v4 6/6] mm: Use common iterator for deferred_init_pages and deferred_free_pages Alexander Duyck
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