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authorZhao Mengmeng <zhaomengmeng@kylinos.cn>2023-04-11 05:52:24 -0400
committerCraig Small <csmall@dropbear.xyz>2023-04-25 07:19:22 +0000
commit25cd1bee0c8025150275252e26c88a7cdf51adb9 (patch)
tree21b9e964b976ee8a0fa1743782f6b5d4daa925db /man
parent833cdc64f06989fc1949d056e8ec11d5cd99e4c0 (diff)
downloadprocps-ng-25cd1bee0c8025150275252e26c88a7cdf51adb9.tar.gz
slabinfo: add comment for cache_size calculation
One of our physical machine shows that the "CACHE SIZE" column of slabtop output is extremely high, three times of the products of objs nums and objs size. After some analysis, we found that the order of slab, which decides "pages per slab", will shrink when memory pressure is high and normal order allocation failed. So we think it might help to add these comments to the man help. Minor fix: add the "memory." back, which is lost after "aa461df0: docs: Minor manpage fixes" Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
Diffstat (limited to 'man')
-rw-r--r--man/slabtop.18
1 files changed, 7 insertions, 1 deletions
diff --git a/man/slabtop.1 b/man/slabtop.1
index edf4784..089fb0e 100644
--- a/man/slabtop.1
+++ b/man/slabtop.1
@@ -104,7 +104,13 @@ The
.B slabtop
statistic header is tracking how many bytes of slabs are being
used and is not a measure of physical memory. The 'Slab' field in the
-\fI/proc/meminfo\fR file is tracking information about used slab physical
+\fI/proc/meminfo\fR file is tracking information about used slab physical memory.
+.PP
+The
+.B CACHE SIZE
+column is not accurate, it's the upper limit of memory used by specific slab. When system
+using slub (most common case) is under high memory pressure, there are slab order
+fallbacks, which means "pages per slab" is not constant and may decrease.
.SH AUTHORS
Written by Chris Rivera and Robert Love.
.PP