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From: Luigi Semenzato <semenzato@google.com>
Date: Wed, 22 Aug 2018 18:50:36 -0700
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Subject: measuring reclaim overhead without NR_PAGES_SCANNED
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To: Linux Memory Management List <linux-mm@kvack.org>

My apologies for not noticing this earlier, but we're often working
with older kernels.

On May 3, 2017 this patch was merged:

commit c822f6223d03c2c5b026a21da09c6b6d523258cd
Author:     Johannes Weiner <hannes@cmpxchg.org>
AuthorDate: Wed May 3 14:52:10 2017 -0700
Commit:     Linus Torvalds <torvalds@linux-foundation.org>
CommitDate: Wed May 3 15:52:08 2017 -0700

    mm: delete NR_PAGES_SCANNED and pgdat_reclaimable()

I was planning to use this number as a measure of how much work the
kernel was doing trying to reclaim pages (by comparing it, for
instance, to the number of pages actually swapped in).  I am not even
sure how good a metric this would be.  Does anybody have suggestions
for a good (or better) replacement?

Thanks!