Maksytka/Linux-Kernel-Programming_2E
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cleanup, better var names

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This commit is contained in:
Kaiwan N Billimoria
2023-12-17 10:59:22 +05:30
parent 8ebdce5751
commit 6d4383932c
1 changed files with 8 additions and 7 deletions
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15
ch8/waste_kmalloc_slabs.sh
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@@ -31,20 +31,21 @@ 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
@@ -52,9 +53,9 @@ 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-"
@@ -62,7 +63,7 @@ sort -k8nr kint.waste | awk 'NF{NF--};1' | uniq | head
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-"