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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-api@vger.kernel.org, Michal Hocko <mhocko@suse.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Tim Murray <timmurray@google.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Daniel Colascione <dancol@google.com>,
	Shakeel Butt <shakeelb@google.com>,
	Sonny Rao <sonnyrao@google.com>,
	oleksandr@redhat.com, hdanton@sina.com, lizeb@google.com,
	Dave Hansen <dave.hansen@intel.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v3 0/5] Introduce MADV_COLD and MADV_PAGEOUT
Date: Thu, 27 Jun 2019 21:06:01 +0300	[thread overview]
Message-ID: <20190627180601.xcppuzia3gk57lq2@box> (raw)
In-Reply-To: <20190627115405.255259-1-minchan@kernel.org>

On Thu, Jun 27, 2019 at 08:54:00PM +0900, Minchan Kim wrote:
> - Problem
> 
> Naturally, cached apps were dominant consumers of memory on the system.
> However, they were not significant consumers of swap even though they are
> good candidate for swap. Under investigation, swapping out only begins
> once the low zone watermark is hit and kswapd wakes up, but the overall
> allocation rate in the system might trip lmkd thresholds and cause a cached
> process to be killed(we measured performance swapping out vs. zapping the
> memory by killing a process. Unsurprisingly, zapping is 10x times faster
> even though we use zram which is much faster than real storage) so kill
> from lmkd will often satisfy the high zone watermark, resulting in very
> few pages actually being moved to swap.

Maybe we should look if we do The Right Thing™ at system-wide level before
introducing new API? How changing swappiness affects your workloads? What
is swappiness value in your setup?

-- 
 Kirill A. Shutemov


  parent reply	other threads:[~2019-06-27 18:06 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-27 11:54 Minchan Kim
2019-06-27 11:54 ` [PATCH v3 1/5] mm: introduce MADV_COLD Minchan Kim
2019-06-27 13:13   ` Dave Hansen
2019-06-27 14:02     ` Michal Hocko
2019-06-27 14:36       ` Dave Hansen
2019-06-27 14:53         ` Michal Hocko
2019-06-27 23:56           ` Minchan Kim
2019-07-01  7:35             ` Minchan Kim
2019-07-09  9:19               ` Michal Hocko
2019-06-27 23:46     ` Minchan Kim
2019-06-27 11:54 ` [PATCH v3 2/5] mm: change PAGEREF_RECLAIM_CLEAN with PAGE_REFRECLAIM Minchan Kim
2019-06-27 11:54 ` [PATCH v3 3/5] mm: account nr_isolated_xxx in [isolate|putback]_lru_page Minchan Kim
2019-07-09  9:38   ` Michal Hocko
2019-06-27 11:54 ` [PATCH v3 4/5] mm: introduce MADV_PAGEOUT Minchan Kim
2019-07-09  9:55   ` Michal Hocko
2019-07-10 10:48     ` Minchan Kim
2019-07-10 11:16       ` Michal Hocko
2019-07-10 11:53         ` Minchan Kim
2019-07-10 19:47           ` Michal Hocko
2019-07-11  0:25             ` Minchan Kim
2019-06-27 11:54 ` [PATCH v3 5/5] mm: factor out pmd young/dirty bit handling and THP split Minchan Kim
2019-07-09 14:10   ` Michal Hocko
2019-07-10 10:56     ` Minchan Kim
2019-06-27 18:06 ` Kirill A. Shutemov [this message]
2019-06-27 23:12   ` [PATCH v3 0/5] Introduce MADV_COLD and MADV_PAGEOUT Minchan Kim
2019-07-01  7:38 ` Minchan Kim
2019-07-01 10:22   ` Michal Hocko

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