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From: Pasha Tatashin <pasha.tatashin@oracle.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
	linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	linux-s390@vger.kernel.org, borntraeger@de.ibm.com,
	heiko.carstens@de.ibm.com, davem@davemloft.net
Subject: Re: [v3 0/9] parallelized "struct page" zeroing
Date: Tue, 30 May 2017 13:16:50 -0400	[thread overview]
Message-ID: <ae992f21-3edf-1ae7-41db-641052e411c7@oracle.com> (raw)
In-Reply-To: <20170529115358.GJ19725@dhcp22.suse.cz>

> Could you be more specific? E.g. how are other stores done in
> __init_single_page safe then? I am sorry to be dense here but how does
> the full 64B store differ from other stores done in the same function.

Hi Michal,

It is safe to do regular 8-byte and smaller stores (stx, st, sth, stb) 
without membar, but they are slower compared to STBI which require a 
membar before memory can be accessed. So when on SPARC we zero a larger 
span of memory it is faster to use STBI, and do one membar at the end. 
This is why for single thread it is faster to zero multiple pages of 
memory and than initialize only fields that are needed in "struct page". 
I believe the same is true for ppc64, as they clear the whole cacheline 
128-bytes at a time with larger memsets.

Pasha

  reply	other threads:[~2017-05-30 17:17 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-05 17:03 [v3 0/9] parallelized "struct page" zeroing Pavel Tatashin
2017-05-05 17:03 ` [v3 1/9] sparc64: simplify vmemmap_populate Pavel Tatashin
2017-05-05 17:03 ` [v3 2/9] mm: defining memblock_virt_alloc_try_nid_raw Pavel Tatashin
2017-05-05 17:03 ` [v3 3/9] mm: add "zero" argument to vmemmap allocators Pavel Tatashin
2017-05-13 19:17   ` kbuild test robot
2017-05-05 17:03 ` [v3 4/9] mm: do not zero vmemmap_buf Pavel Tatashin
2017-05-05 17:03 ` [v3 5/9] mm: zero struct pages during initialization Pavel Tatashin
2017-05-05 17:03 ` [v3 6/9] sparc64: teach sparc not to zero struct pages memory Pavel Tatashin
2017-05-05 17:03 ` [v3 7/9] x86: teach x86 " Pavel Tatashin
2017-05-05 17:03 ` [v3 8/9] powerpc: teach platforms " Pavel Tatashin
2017-05-05 17:03 ` [v3 9/9] s390: " Pavel Tatashin
2017-05-08 11:36   ` Heiko Carstens
2017-05-15 18:24     ` Pasha Tatashin
2017-05-15 23:17       ` Heiko Carstens
2017-05-16  0:33         ` Pasha Tatashin
2017-05-09 18:12 ` [v3 0/9] parallelized "struct page" zeroing Michal Hocko
2017-05-09 18:54   ` Pasha Tatashin
2017-05-10  7:24     ` Michal Hocko
2017-05-10 13:42       ` Pasha Tatashin
2017-05-10 14:57         ` Michal Hocko
2017-05-10 15:01           ` Pasha Tatashin
2017-05-10 15:20             ` David Miller
2017-05-11 20:47             ` Pasha Tatashin
2017-05-11 20:59               ` Pasha Tatashin
2017-05-12 16:57                 ` David Miller
2017-05-12 17:24                   ` Pasha Tatashin
2017-05-12 17:37                     ` David Miller
2017-05-16 23:50                       ` Benjamin Herrenschmidt
2017-05-12 16:56               ` David Miller
2017-05-10 15:19           ` David Miller
2017-05-10 17:17             ` Matthew Wilcox
2017-05-10 18:00               ` David Miller
2017-05-10 21:11                 ` Matthew Wilcox
2017-05-11  8:05             ` Michal Hocko
2017-05-11 14:35               ` David Miller
2017-05-15 18:12   ` Pasha Tatashin
2017-05-15 19:38     ` Michal Hocko
2017-05-15 20:44       ` Pasha Tatashin
2017-05-16  8:36         ` Michal Hocko
2017-05-26 16:45           ` Pasha Tatashin
2017-05-29 11:53             ` Michal Hocko
2017-05-30 17:16               ` Pasha Tatashin [this message]
2017-05-31 16:31                 ` Michal Hocko
2017-05-31 16:51                   ` David Miller
2017-06-01  3:35                   ` Pasha Tatashin
2017-06-01  8:46                     ` Michal Hocko

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