From: Dave Hansen <dave.hansen@intel.com>
To: Suleiman Souhlal <suleiman@google.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, dan.j.williams@intel.com
Subject: Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard
Date: Thu, 17 Oct 2019 09:32:02 -0700 [thread overview]
Message-ID: <85512332-d9d4-6a72-0b42-a8523abc1b5f@intel.com> (raw)
In-Reply-To: <CABCjUKDWRJO9s68qhKQGXzrW39KqfZzZhoOX0HgDcnv-RxJZPw@mail.gmail.com>
On 10/17/19 9:01 AM, Suleiman Souhlal wrote:
> One problem that came up is that if you get into direct reclaim,
> because persistent memory can have pretty low write throughput, you
> can end up stalling users for a pretty long time while migrating
> pages.
Basically, you're saying that memory load spikes turn into latency spikes?
FWIW, we have been benchmarking this sucker with benchmarks that claim
to care about latency. In general, compared to DRAM, we do see worse
latency, but nothing catastrophic yet. I'd be interested if you have
any workloads that act as reasonable proxies for your latency requirements.
> Because of that, we moved to a solution based on the proactive reclaim
> of idle pages, that was presented at LSFMM earlier this year:
> https://lwn.net/Articles/787611/ .
I saw the presentation. The feedback in the room as I remember it was
that proactive reclaim essentially replaced the existing reclaim
mechanism, to which the audience was not receptive. Have folks opinions
changed on that, or are you looking for other solutions?
next prev parent reply other threads:[~2019-10-17 16:32 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 22:11 Dave Hansen
2019-10-16 22:11 ` [PATCH 1/4] node: Define and export memory migration path Dave Hansen
2019-10-17 11:12 ` Kirill A. Shutemov
2019-10-17 11:44 ` Kirill A. Shutemov
2019-10-16 22:11 ` [PATCH 2/4] mm/migrate: Defer allocating new page until needed Dave Hansen
2019-10-17 11:27 ` Kirill A. Shutemov
2019-10-16 22:11 ` [PATCH 3/4] mm/vmscan: Attempt to migrate page in lieu of discard Dave Hansen
2019-10-17 17:30 ` Yang Shi
2019-10-18 18:15 ` Dave Hansen
2019-10-18 21:02 ` Yang Shi
2019-10-16 22:11 ` [PATCH 4/4] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2019-10-17 3:45 ` [PATCH 0/4] [RFC] Migrate Pages in lieu of discard Shakeel Butt
2019-10-17 14:26 ` Dave Hansen
2019-10-17 16:58 ` Shakeel Butt
2019-10-17 20:51 ` Dave Hansen
2019-10-17 17:20 ` Yang Shi
2019-10-17 21:05 ` Dave Hansen
2019-10-17 22:58 ` Shakeel Butt
2019-10-18 21:44 ` Yang Shi
2019-10-17 16:01 ` Suleiman Souhlal
2019-10-17 16:32 ` Dave Hansen [this message]
2019-10-17 16:39 ` Shakeel Butt
2019-10-18 8:11 ` Suleiman Souhlal
2019-10-18 15:10 ` Dave Hansen
2019-10-18 15:39 ` Suleiman Souhlal
2019-10-18 7:44 ` Michal Hocko
2019-10-18 14:54 ` Dave Hansen
2019-10-18 21:39 ` Yang Shi
2019-10-18 21:55 ` Dan Williams
2019-10-22 13:49 ` Michal Hocko
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