Merge branch 'main' of https://github.com/PacktPublishing/Linux-Kerne…

…l-Programming_2E

ch8/slab4_actualsz_wstg_plot/Readme

@@ -16,7 +16,7 @@ sudo dmesg -C
 2. Now build the module and insmod it (it will fail at some point, that's fine)
 ../../lkm slab4_actualsz_wstg_plot
 
-3. Run the helper script plot_graph.sh; f.e.:
+3. Run the helper script plot_graph.sh:
 
 (Recommended: Before running the script, pl check the data file; it should ONLY
 have data of the form:

ch8/slab4_actualsz_wstg_plot/plotdata.txt

@@ -203,4 +203,208 @@
 4137060,1
 4157540,0
 4178020,0
-<intr>,ipv6:addrconf_verify_rtnl:4618:,IPv6:,now,=,4302957104,,schedule,=,4302987241,,rounded,schedule,=,4302987491,=>,4302987241
+100,28
+20580,59
+41060,59
+61540,6
+82020,59
+102500,27
+122980,6
+143460,82
+163940,59
+184420,42
+204900,27
+225380,16
+245860,6
+266340,96
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+532580,96
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+614500,70
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+860260,21
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+3154020,32
+3174500,32
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+4116580,1
+4137060,1
+4157540,0
+4178020,0

ch8/waste_kmalloc_slabs.sh

@@ -31,38 +31,39 @@ do
  # /sys/kernel/debug/slab/kmalloc-8/alloc_traces:     58 strndup_user+0x4a/0x70 waste=406/7 age=831078/831403/831933 pid=1-801 cpus=0-5 406
  # -----kmalloc-<foo> slab----------------------: num-times-requested func+start/len waste=num_wasted_total/num_wasted_eachtime pid=<...> cpus=<...> 
 
- # Get the absolute wastage:
+ # Get the total wastage (the x in waste=x/y; y = # bytes wasted each time):
  # Kernel modules contain an extra field, the module name [foo]
  # So get the field# of the column having the string 'waste=' ...
  waste_fieldnum=$(echo "${rec}" | awk '{for(i=1;i<=NF;i++) {if ($i ~ /waste=/) print i}}')
  # ... and then extract the absolute number of wasted bytes based on it
  # (of the form: waste=406/7, i.e., waste=num_wasted_total/num_wasted_eachtime)
- wastage_abs=$(echo "${rec}" | awk -v fld=${waste_fieldnum} '{print $fld}'|cut -d= -f2|cut -d/ -f1)
- echo "${rec} ${wastage_abs}" >> ${TMPF}
+ num_wasted_total=$(echo "${rec}" | awk -v fld=${waste_fieldnum} '{print $fld}'|cut -d= -f2|cut -d/ -f1)
+ #echo "wstg_abs= ${wastage_abs}"
+ echo "${rec} ${num_wasted_total}" >> ${TMPF}
  let n=n+1
  [[ $((n % 100)) -eq 0 ]] && echo -n "."
 done
 echo
 
-# separate out kernel internal kmalloc-* slabs from kernel modules slabs
+# Separate out kernel internal kmalloc-* slabs from kernel modules slabs
 grep -v "\[.*\]" ${TMPF} > kint.waste || true
 grep "\[.*\]" ${TMPF} > kmods.waste || true
 
 echo "======== Wastage (highest-to-lowest with duplicate lines eliminated) ========"
 echo "--------------- kernel internal ----------------
    Top 10 wasters (in desc order). (To see all, lookup the full report here: kint.waste)"
 [[ -s kint.waste ]] && {
-# kernel internal - the 8th fields is the number of 'waste' bytes
+# kernel internal - the 8th fields is the total number of 'waste' bytes
 # (As the abs number of wasted bytes is already there in the output, we use awk
-#  to eliminate the last col, the number of wasted bytes)
+#  to eliminate the last col, the total number of wasted bytes)
 # Also, use uniq(1) to eliminate duplicate lines (?)
 sort -k8nr kint.waste | awk 'NF{NF--};1' | uniq | head
 } || echo "-none-"
 
 echo "
 --------------- kernel modules ----------------
    Top 10 wasters (in desc order). (To see all, lookup the full report here: kmods.waste)"
-# kernel modules - the 9th fields is the number of 'waste' bytes
+# kernel modules - the 9th fields is the total number of 'waste' bytes
 [[ -s kmods.waste ]] && {
 sort -k9nr kmods.waste | awk 'NF{NF--};1' | uniq | head
 } || echo "-none-"