linux-kernel - Re: [PATCH v2 09/16] rcu/tree: Maintain separate array for vmalloc ptrs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200622190406.GA3787@pc636>
Date:   Mon, 22 Jun 2020 21:04:06 +0200
From:   Uladzislau Rezki <urezki@...il.com>
To:     "Paul E. McKenney" <paulmck@...nel.org>, linux-mm@...ck.org
Cc:     Uladzislau Rezki <urezki@...il.com>,
        Matthew Wilcox <willy@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Theodore Y . Ts'o" <tytso@....edu>,
        Joel Fernandes <joel@...lfernandes.org>,
        RCU <rcu@...r.kernel.org>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>
Subject: Re: [PATCH v2 09/16] rcu/tree: Maintain separate array for vmalloc
 ptrs

> > > 
> > > Very good.  When does kfree_rcu() and friends move out of kernel/rcu?
> > > 
> > Do you mean to move the whole logic of kfree_rcu() from top to down to mm/?
> 
> I do mean exactly that.
> 
> That was my goal some years back when Rao Shoaib was making the first
> attempt along these lines, and it remains my goal.  After all, if this
> effort is at all successful, the coupling between kfree_rcu() with
> slab/slob/slub will become much tighter than that between kfree_rcu()
> and RCU.
> 
> There will need to be some additional RCU APIs used by kfree_rcu(),
> for example, something to tell RCU how many blocks are awaiting a
> grace period.  But these are narrow and easily defined APIs.
>
I also think that k[v]free_rcu() should reside somewhere under "mm/".
Currently they are defined as macros under "linux/rcupdate.h". So i
am not sure if definitions should stay there or moved also.

Implementation of the k[v]free_rcu() is under rcu/tree.c and for tiny
variant is under rcutiny.h. It can be moved to the mm/slab_common.c
or independent files can be created. I think, mm people should consult
what is the best way to go :)

Any thoughts on it?

Thank you!

--
Vlad Rezki