<s>
In	O
real-time	B-General_Concept
computing	I-General_Concept
,	O
priority	B-Operating_System
inheritance	I-Operating_System
is	O
a	O
method	O
for	O
eliminating	O
unbounded	O
priority	B-Operating_System
inversion	I-Operating_System
.	O
</s>
<s>
Using	O
this	O
programming	B-General_Concept
method	O
,	O
a	O
process	O
scheduling	O
algorithm	O
increases	O
the	O
priority	O
of	O
a	O
process	O
(	O
A	O
)	O
to	O
the	O
maximum	O
priority	O
of	O
any	O
other	O
process	O
waiting	O
for	O
any	O
resource	B-General_Concept
on	O
which	O
A	O
has	O
a	O
resource	B-Operating_System
lock	I-Operating_System
(	O
if	O
it	O
is	O
higher	O
than	O
the	O
original	O
priority	O
of	O
A	O
)	O
.	O
</s>
<s>
The	O
basic	O
idea	O
of	O
the	O
priority	B-Operating_System
inheritance	I-Operating_System
protocol	O
is	O
that	O
when	O
a	O
job	O
blocks	O
one	O
or	O
more	O
high-priority	O
jobs	O
,	O
it	O
ignores	O
its	O
original	O
priority	O
assignment	O
and	O
executes	O
its	O
critical	B-Operating_System
section	I-Operating_System
at	O
an	O
elevated	O
priority	O
level	O
.	O
</s>
<s>
After	O
executing	O
its	O
critical	B-Operating_System
section	I-Operating_System
and	O
releasing	O
its	O
locks	O
,	O
the	O
process	O
returns	O
to	O
its	O
original	O
priority	O
level	O
.	O
</s>
<s>
Suppose	O
that	O
both	O
H	O
and	O
L	O
require	O
some	O
shared	O
resource	B-General_Concept
.	O
</s>
<s>
If	O
L	O
acquires	O
this	O
shared	O
resource	B-General_Concept
(	O
entering	O
a	O
critical	B-Operating_System
section	I-Operating_System
)	O
,	O
and	O
H	O
subsequently	O
requires	O
it	O
,	O
H	O
will	O
block	O
until	O
L	O
releases	O
it	O
(	O
leaving	O
its	O
critical	B-Operating_System
section	I-Operating_System
)	O
.	O
</s>
<s>
Without	O
priority	B-Operating_System
inheritance	I-Operating_System
,	O
process	O
M	O
could	O
preempt	B-Operating_System
process	O
L	O
during	O
the	O
critical	B-Operating_System
section	I-Operating_System
and	O
delay	O
its	O
completion	O
,	O
in	O
effect	O
causing	O
the	O
lower-priority	O
process	O
M	O
to	O
indirectly	O
preempt	B-Operating_System
the	O
high-priority	O
process	O
H	O
.	O
This	O
is	O
a	O
priority	B-Operating_System
inversion	I-Operating_System
bug	O
.	O
</s>
<s>
With	O
priority	B-Operating_System
inheritance	I-Operating_System
,	O
L	O
will	O
execute	O
its	O
critical	B-Operating_System
section	I-Operating_System
at	O
H	O
's	O
high	O
priority	O
whenever	O
H	O
is	O
blocked	O
on	O
the	O
shared	O
resource	B-General_Concept
.	O
</s>
<s>
As	O
a	O
result	O
,	O
M	O
will	O
be	O
unable	O
to	O
preempt	B-Operating_System
L	O
and	O
will	O
be	O
blocked	O
.	O
</s>
<s>
That	O
is	O
,	O
the	O
higher-priority	O
job	O
M	O
must	O
wait	O
for	O
the	O
critical	B-Operating_System
section	I-Operating_System
of	O
the	O
lower	O
priority	O
job	O
L	O
to	O
be	O
executed	O
,	O
because	O
L	O
has	O
inherited	O
H	O
's	O
priority	O
.	O
</s>
<s>
When	O
L	O
exits	O
its	O
critical	B-Operating_System
section	I-Operating_System
,	O
it	O
regains	O
its	O
original	O
(	O
low	O
)	O
priority	O
and	O
awakens	O
H	O
(	O
which	O
was	O
blocked	O
by	O
L	O
)	O
.	O
</s>
<s>
This	O
enables	O
M	O
and	O
L	O
to	O
resume	O
in	O
succession	O
and	O
run	O
to	O
completion	O
without	O
priority	B-Operating_System
inversion	I-Operating_System
.	O
</s>
