From: Mike Rapoport <rppt@linux.vnet.ibm.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
linux-mm <linux-mm@kvack.org>,
lkml <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH] mm: introduce MADV_CLR_HUGEPAGE
Date: Thu, 1 Jun 2017 09:53:02 +0300 [thread overview]
Message-ID: <20170601065302.GA30495@rapoport-lnx> (raw)
In-Reply-To: <20170530143941.GK7969@dhcp22.suse.cz>
On Tue, May 30, 2017 at 04:39:41PM +0200, Michal Hocko wrote:
> On Tue 30-05-17 16:04:56, Andrea Arcangeli wrote:
> >
> > UFFDIO_COPY while not being a major slowdown for sure, it's likely
> > measurable at the microbenchmark level because it would add a
> > enter/exit kernel to every 4k memcpy. It's not hard to imagine that as
> > measurable. How that impacts the total precopy time I don't know, it
> > would need to be benchmarked to be sure.
>
> Yes, please!
I've run a simple test (below) that fills 1G of memory either with memcpy
of ioctl(UFFDIO_COPY) in 4K chunks.
The machine I used has two "Intel(R) Xeon(R) CPU E5-2680 0 @ 2.70GHz" and
128G of RAM.
I've averaged elapsed time reported by /usr/bin/time over 100 runs and here
what I've got:
memcpy with THP on: 0.3278 sec
memcpy with THP off: 0.5295 sec
UFFDIO_COPY: 0.44 sec
That said, for the CRIU usecase UFFDIO_COPY seems faster that disabling THP
and then doing memcpy.
--
Sincerely yours,
Mike.
----------------------------------------------------------
{
...
src = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (src == MAP_FAILED)
fprintf(stderr, "map src failed\n"), exit(1);
*((unsigned long *)src) = 1;
if (disable_huge && prctl(PR_SET_THP_DISABLE, 1, 0, 0, 0))
fprintf(stderr, "ptctl failed\n"), exit(1);
dst = mmap(NULL, page_size * nr_pages, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (dst == MAP_FAILED)
fprintf(stderr, "map dst failed\n"), exit(1);
if (use_uffd && userfaultfd_register(dst))
fprintf(stderr, "userfault_register failed\n"), exit(1);
for (i = 0; i < nr_pages; i++) {
char *address = dst + i * page_size;
if (use_uffd) {
struct uffdio_copy uffdio_copy;
uffdio_copy.dst = (unsigned long)address;
uffdio_copy.src = (unsigned long)src;
uffdio_copy.len = page_size;
uffdio_copy.mode = 0;
uffdio_copy.copy = 0;
ret = ioctl(uffd, UFFDIO_COPY, &uffdio_copy);
if (ret)
fprintf(stderr, "copy: %d, %d\n", ret, errno),
exit(1);
} else {
memcpy(address, src, page_size);
}
}
return 0;
}
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-06-01 6:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1495433562-26625-1-git-send-email-rppt@linux.vnet.ibm.com>
[not found] ` <20170522114243.2wrdbncilozygbpl@node.shutemov.name>
[not found] ` <20170522133559.GE27382@rapoport-lnx>
[not found] ` <20170522135548.GA8514@dhcp22.suse.cz>
[not found] ` <20170522142927.GG27382@rapoport-lnx>
[not found] ` <a9e74c22-1a07-f49a-42b5-497fee85e9c9@suse.cz>
[not found] ` <20170524075043.GB3063@rapoport-lnx>
2017-05-24 7:58 ` [PATCH] mm: introduce MADV_CLR_HUGEPAGE Vlastimil Babka
2017-05-24 10:39 ` Mike Rapoport
2017-05-24 11:18 ` Michal Hocko
2017-05-24 14:25 ` Pavel Emelyanov
2017-05-24 14:27 ` Mike Rapoport
2017-05-24 15:22 ` Andrea Arcangeli
2017-05-30 7:44 ` Michal Hocko
[not found] ` <20170530074408.GA7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 10:19 ` Mike Rapoport
2017-05-30 10:39 ` Michal Hocko
[not found] ` <20170530103930.GB7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 14:04 ` Andrea Arcangeli
2017-05-30 14:39 ` Michal Hocko
[not found] ` <20170530143941.GK7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 14:56 ` Michal Hocko
[not found] ` <20170530145632.GL7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 16:06 ` Andrea Arcangeli
2017-05-31 6:30 ` Vlastimil Babka
2017-05-31 8:24 ` Michal Hocko
2017-05-31 9:27 ` Mike Rapoport
2017-05-31 10:24 ` Michal Hocko
[not found] ` <20170531082414.GB27783-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-31 10:22 ` Michal Hocko
2017-06-01 11:00 ` Mike Rapoport
2017-06-01 12:27 ` Michal Hocko
2017-05-30 15:43 ` Andrea Arcangeli
2017-05-31 12:08 ` Michal Hocko
[not found] ` <20170531120822.GL27783-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-31 12:39 ` Mike Rapoprt
2017-05-31 14:18 ` Andrea Arcangeli
[not found] ` <20170531141809.GB302-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-05-31 14:32 ` Michal Hocko
2017-05-31 15:46 ` Andrea Arcangeli
2017-06-01 6:58 ` Mike Rapoport
[not found] ` <8FA5E4C2-D289-4AF5-AA09-6C199E58F9A5-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-05-31 14:19 ` Michal Hocko
2017-06-01 6:53 ` Mike Rapoport [this message]
2017-06-01 8:09 ` Michal Hocko
[not found] ` <20170601080909.GD32677-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-06-01 8:35 ` Mike Rapoport
2017-06-01 13:45 ` Andrea Arcangeli
2017-06-02 9:11 ` Mike Rapoport
2017-05-31 9:08 ` Mike Rapoport
2017-05-31 12:05 ` Michal Hocko
2017-05-31 12:25 ` Mike Rapoprt
2017-05-24 11:31 ` Vlastimil Babka
2017-05-24 14:28 ` Pavel Emelyanov
2017-05-24 14:54 ` Vlastimil Babka
2017-05-24 15:13 ` Mike Rapoport
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170601065302.GA30495@rapoport-lnx \
--to=rppt@linux.vnet.ibm.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=kirill.shutemov@linux.intel.com \
--cc=kirill@shutemov.name \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=vbabka@suse.cz \
--cc=xemul@virtuozzo.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).