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From: Vlastimil Babka <vbabka@suse.cz>
To: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
	Michal Hocko <mhocko@kernel.org>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	l.roehrs@profihost.ag, cgroups@vger.kernel.org,
	Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: lot of MemAvailable but falling cache and raising PSI
Date: Mon, 9 Sep 2019 14:21:10 +0200	[thread overview]
Message-ID: <ec45c3f9-5649-fb39-ecf8-6ca7620a6e2a@suse.cz> (raw)
In-Reply-To: <3ca34a49-6327-e6fd-2754-9b0700d87785@profihost.ag>

On 9/9/19 2:09 PM, Stefan Priebe - Profihost AG wrote:
> 
> Am 09.09.19 um 13:49 schrieb Vlastimil Babka:
>> On 9/9/19 10:54 AM, Stefan Priebe - Profihost AG wrote:
>>>> Do you have more snapshots of /proc/vmstat as suggested by Vlastimil and
>>>> me earlier in this thread? Seeing the overall progress would tell us
>>>> much more than before and after. Or have I missed this data?
>>>
>>> I needed to wait until today to grab again such a situation but from
>>> what i know it is very clear that MemFree is low and than the kernel
>>> starts to drop the chaches.
>>>
>>> Attached you'll find two log files.
>>
>> Thanks, what about my other requests/suggestions from earlier?
> 
> Sorry i missed your email.
> 
>> 1. How does /proc/pagetypeinfo look like?
> 
> # cat /proc/pagetypeinfo
> Page block order: 9
> Pages per block:  512

Looks like it might be fragmented, but was that snapshot taken in the 
situation where there's free memory and the system still drops cache?

>> 2. Could you also try if the bad trend stops after you execute:
>>   echo never > /sys/kernel/mm/transparent_hugepage/defrag
>> and report the result?
> 
> it's pretty difficult to catch those moments. Is it OK so set the value
> now and monitor if it happens again?

Well if it doesn't happen again after changing that setting, it would 
definitely point at THP interactions.

> Just to let you know:
> I've now also some more servers where memfree show 10-20Gb but cache
> drops suddently and memory PSI raises.

You mean those are in that state right now? So how does 
/proc/pagetypeinfo look there, and would changing the defrag setting help?

> Greets,
> Stefan
> 



  reply	other threads:[~2019-09-09 12:21 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05 11:27 lot of MemAvailable but falling cache and raising PSI Stefan Priebe - Profihost AG
2019-09-05 11:40 ` Michal Hocko
2019-09-05 11:56   ` Stefan Priebe - Profihost AG
2019-09-05 16:28     ` Yang Shi
2019-09-05 17:26       ` Stefan Priebe - Profihost AG
2019-09-05 18:46         ` Yang Shi
2019-09-05 19:31           ` Stefan Priebe - Profihost AG
2019-09-06 10:08     ` Stefan Priebe - Profihost AG
2019-09-06 10:25       ` Vlastimil Babka
2019-09-06 18:52       ` Yang Shi
2019-09-07  7:32         ` Stefan Priebe - Profihost AG
2019-09-09  8:27       ` Michal Hocko
2019-09-09  8:54         ` Stefan Priebe - Profihost AG
2019-09-09 11:01           ` Michal Hocko
2019-09-09 12:08             ` Michal Hocko
2019-09-09 12:10               ` Stefan Priebe - Profihost AG
2019-09-09 12:28                 ` Michal Hocko
2019-09-09 12:37                   ` Stefan Priebe - Profihost AG
2019-09-09 12:49                     ` Michal Hocko
2019-09-09 12:56                       ` Stefan Priebe - Profihost AG
     [not found]                         ` <52235eda-ffe2-721c-7ad7-575048e2d29d@profihost.ag>
2019-09-10  5:58                           ` Stefan Priebe - Profihost AG
2019-09-10  8:29                           ` Michal Hocko
2019-09-10  8:38                             ` Stefan Priebe - Profihost AG
2019-09-10  9:02                               ` Michal Hocko
2019-09-10  9:37                                 ` Stefan Priebe - Profihost AG
2019-09-10 11:07                                   ` Michal Hocko
2019-09-10 12:45                                     ` Stefan Priebe - Profihost AG
2019-09-10 12:57                                       ` Michal Hocko
2019-09-10 13:05                                         ` Stefan Priebe - Profihost AG
2019-09-10 13:14                                           ` Stefan Priebe - Profihost AG
2019-09-10 13:24                                             ` Michal Hocko
2019-09-11  6:12                                               ` Stefan Priebe - Profihost AG
2019-09-11  6:24                                                 ` Stefan Priebe - Profihost AG
2019-09-11 13:59                                                   ` Stefan Priebe - Profihost AG
2019-09-12 10:53                                                     ` Stefan Priebe - Profihost AG
2019-09-12 11:06                                                       ` Stefan Priebe - Profihost AG
2019-09-11  7:09                                                 ` 5.3-rc-8 hung task in IO (was: Re: lot of MemAvailable but falling cache and raising PSI) Michal Hocko
2019-09-11 14:09                                                   ` Stefan Priebe - Profihost AG
2019-09-11 14:56                                                   ` Filipe Manana
2019-09-11 14:56                                                     ` Filipe Manana
2019-09-11 15:39                                                     ` Stefan Priebe - Profihost AG
2019-09-11 15:56                                                       ` Filipe Manana
2019-09-11 15:56                                                         ` Filipe Manana
2019-09-11 16:15                                                         ` Stefan Priebe - Profihost AG
2019-09-11 16:19                                                           ` Filipe Manana
2019-09-11 16:19                                                             ` Filipe Manana
2019-09-19 10:21                                                 ` lot of MemAvailable but falling cache and raising PSI Stefan Priebe - Profihost AG
2019-09-23 12:08                                                   ` Michal Hocko
2019-09-27 12:45                                                   ` Vlastimil Babka
2019-09-30  6:56                                                     ` Stefan Priebe - Profihost AG
2019-09-30  7:21                                                       ` Vlastimil Babka
2019-10-22  7:41                                                     ` Stefan Priebe - Profihost AG
2019-10-22  7:48                                                       ` Vlastimil Babka
2019-10-22 10:02                                                         ` Stefan Priebe - Profihost AG
2019-10-22 10:20                                                           ` Oscar Salvador
2019-10-22 10:21                                                           ` Vlastimil Babka
2019-10-22 11:08                                                             ` Stefan Priebe - Profihost AG
2019-09-10  5:41                       ` Stefan Priebe - Profihost AG
2019-09-09 11:49           ` Vlastimil Babka
2019-09-09 12:09             ` Stefan Priebe - Profihost AG
2019-09-09 12:21               ` Vlastimil Babka [this message]
2019-09-09 12:31                 ` Stefan Priebe - Profihost AG
2019-09-05 12:15 ` Vlastimil Babka
2019-09-05 12:27   ` Stefan Priebe - Profihost AG

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