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when I run the atop -r /var/log/atop/...

I see from the atop screen this

 PAG | scan  641376 |  steal 635209 | stall

the PAG is colored with red

can someone explain what PAG explain from the atop , and what this problem means ?

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1 Answer 1

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man atop

PAG Paging frequency. This line contains the number of scanned pages ('scan') due to the fact that free memory drops below a particular threshold and the number times that the kernel tries to reclaim pages due to an urgent need (`stall').

Also the number of memory pages the system read from swap space ('swin') > and the number of memory pages the system wrote to swap space ('swout') > are shown.

Basically, it (normally) indicates that your system is low on memory, which is not a good thing, hence it is in red.

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  • so your suggestion is to increase the memory ?, and how to configure the memory pages ? according to what ?
    – yael
    Commented Nov 1, 2016 at 10:53
  • > so your suggestion is to increase the memory ? Well, probably, your original question was on what PAG is, so I've provided you with a description of it.
    – zeppelin
    Commented Nov 1, 2016 at 11:04
  • > and how to configure the memory pages ? according to what ? You will normally just configure the total memory (and swap) limits, as pages are low level kernel thing, not something you have to reconfigure during the normal operation.
    – zeppelin
    Commented Nov 1, 2016 at 11:08
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    What does "steal" relate to? The atop man-page describes (cycle?) stealing in the context of virtual machines, but that does not seem to be what is shown under PAG.
    – Timo Reimann
    Commented Nov 8, 2019 at 15:46
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    @TimoReimann according to sar(1) Number of pages the system has reclaimed from cache (pagecache and swapcache) per second to satisfy its memory demands.
    – azat
    Commented Jan 21, 2020 at 9:49

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