Hi Zhouyi,
On Tue, 21 Dec 2021 06:42:04 +0800, Zhouyi Zhou wrote:
> Thanks Paul and Akira
>
> great improvement to perfbook's glossary!
>
> A question below ;-)
>
> On Tue, Dec 21, 2021 at 4:15 AM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>>
>> On Mon, Dec 20, 2021 at 06:55:36PM +0900, Akira Yokosawa wrote:
>>> Hi Paul,
>>>
>>> While reading through Section 9.5.4, I noticed a few terms
>>> I'd like to see in perfbook's Glossary.
>>>
>>> - Reference Counter/Counting
>>> - Existence Guarantee
>>> - Type-safe Memory
>>>
>>> "Reference counter" is already mentioned in a couple of existing
>>> items in the glossary.
>>>
>>> "Existing guarantee" might be obvious enough and not worthy
>>> to be in the glossary.
>>>
>>> Thoughts?
>>>
>>> There were only a few minor nits in the section.
>>> Will post a patch taking care of them.
>>
>> Thank you for looking it over! Please see below for a proposed patch
>> to the glossary. Oh, and thank you for the checking utilities, very
>> nice to get explicit messages rather than subtlely broken formatting!!!
>>
>> utilities/punctcheck.sh
>> ./glossary.tex:547: Type-safe memory\cite{Cheriton96a} is provided by a
>> utilities/cleverefcheck.sh
>>
>> Thanx, Paul
>>
>> ------------------------------------------------------------------------
>>
>> commit a8f5948a1b8921941bf4039e278aa7929f64c322
>> Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
>> Date: Mon Dec 20 09:41:55 2021 -0800
>>
>> glossary: Add reference count, existence guarantee, and TSM
>>
>> Where "TSM" is type-safe memory.
>>
>> Reported-by: Akira Yokosawa <akiyks@xxxxxxxxx>
>> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
>>
>> diff --git a/glossary.tex b/glossary.tex
>> index be10f703..31c09232 100644
>> --- a/glossary.tex
>> +++ b/glossary.tex
>> @@ -199,6 +199,14 @@
>> increase the overall cost of the computation, resulting in
>> linear speedups as threads are added (assuming sufficient
>> CPUs are available).
>> +\item[\IX{Existence Guarantee}:]
>> + An existence guarantee is provided by a synchronization mechanism
>> + that prevents a given dynamically allocated object from being
>> + freed for the duration of that guarantee.
>> + For example, RCU provides existence guarantees for the duration
>> + of RCU read-side critical sections.
>> + A similar but strictly weaker guarantee is provided by
>> + type-safe memory.
> here type-safe memory is called 'weaker'
Yes.
>
>> \item[\IXh{Exclusive}{Lock}:]
>> An exclusive lock is a mutual-exclusion mechanism that
>> permits only one thread at a time into the
>> @@ -469,6 +477,11 @@
>> A situation in which getting the correct result is not sufficient,
>> but where this result must also be obtained within a given amount
>> of time.
>> +\item[\IX{Reference Count}:]
>> + A counter that tracks the number of users of a given object or
>> + entity.
>> + Reference counters provide existence guarantees and are sometimes
>> + used to implement garbage collectors.
>> \item[\IX{Scalability}:]
>> A measure of how effectively a given system is able to utilize
>> additional resources.
>> @@ -531,6 +544,17 @@
>> A synchronization mechanism that gathers groups of memory
>> accesses so as to execute them atomically from the viewpoint
>> of transactions on other CPUs or threads.
>> +\item[\IX{Type-Safe Memory}:]
>> + Type-safe memory~\cite{Cheriton96a} is provided by a
>> + synchronization mechanism that prevents a given dynamically
>> + allocated object from changing to an incompatible type.
>> + Note that the object might well be freed and then reallocated, but
>> + the reallocated object is guaranteed to be of a compatible type.
>> + Within the Linux kernel, type-safe memory is provided within
>> + RCU read-side critical sections for memory allocated from slabs
>> + marked with the \co{SLAB_TYPESAFE_BY_RCU} flag.
>> + The strictly stronger existence guarantee also prevents freeing
>> + of the protected object.
> but why do we use "stronger" here (should not it be "weaker"?)
Here, "strictly stronger" modifies "existence guarantee".
So there is no inconsistency, I suppose.
Thanks, Akira
>
>> \item[\IX{Unteachable}:]
>> A topic, concept, method, or mechanism that the teacher does
>> not understand well is therefore uncomfortable teaching.
> Many thanks
> Zhouyi
>
