Re: [PATCH 09/24] rcu/tree: cache specified number of objects

From: joel
Date: Mon May 04 2020 - 16:16:01 EST




On May 4, 2020 3:51:28 PM EDT, Uladzislau Rezki <urezki@xxxxxxxxx> wrote:
>> > > Since we don't care about traversing backwards, isn't it better
>to use llist
>> > > for this usecase?
>> > >
>> > > I think Vlad is using locking as we're also tracking the size of
>the llist to
>> > > know when to free pages. This tracking could suffer from the
>lost-update
>> > > problem without any locking, 2 lockless llist_add happened
>simulatenously.
>> > >
>> > > Also if list_head is used, it will take more space and still use
>locking.
>> >
>> > Indeed, it would be best to use a non-concurrent singly linked
>list.
>>
>> Ok cool :-)
>>
>> Is it safe to say something like the following is ruled out? ;-) :-D
>> #define kfree_rcu_list_add llist_add
>>
>In that case i think it is better just to add a comment about using
>llist_head. To state that it used as a singular list to save space
>and the access is synchronized by the lock :)
>
>IMHO.

Sounds good to me. thanks,

- Joel

>
>--
>Vlad Rezki

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