min/low/high_wmark_pages(z) is defined as
  (z->_watermark[WMARK_MIN/LOW/HIGH] + z->watermark_boost)
If kswapd is frequently woken up due to the increase of
min/low/high_wmark_pages, printing watermark_boost can quickly locate
whether watermark_boost or _watermark[WMARK_MIN/LOW/HIGH] caused
min/low/high_wmark_pages to increase.
Link: https://lkml.kernel.org/r/1632472566-12246-1-git-send-email-liangcaifan19@gmail.com
Signed-off-by: Liangcai Fan <liangcaifan19@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
                printk(KERN_CONT
                        "%s"
                        " free:%lukB"
+                       " boost:%lukB"
                        " min:%lukB"
                        " low:%lukB"
                        " high:%lukB"
                        "\n",
                        zone->name,
                        K(zone_page_state(zone, NR_FREE_PAGES)),
+                       K(zone->watermark_boost),
                        K(min_wmark_pages(zone)),
                        K(low_wmark_pages(zone)),
                        K(high_wmark_pages(zone)),
 
        }
        seq_printf(m,
                   "\n  pages free     %lu"
+                  "\n        boost    %lu"
                   "\n        min      %lu"
                   "\n        low      %lu"
                   "\n        high     %lu"
                   "\n        managed  %lu"
                   "\n        cma      %lu",
                   zone_page_state(zone, NR_FREE_PAGES),
+                  zone->watermark_boost,
                   min_wmark_pages(zone),
                   low_wmark_pages(zone),
                   high_wmark_pages(zone),