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From: Christopher Lameter <cl@linux.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Waiman Long <longman@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	selinux@vger.kernel.org, Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Eric Paris <eparis@parisplace.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: Re: [PATCH 2/4] signal: Make flush_sigqueue() use free_q to release memory
Date: Mon, 25 Mar 2019 14:15:25 +0000	[thread overview]
Message-ID: <01000169b534b9e8-31a2af2c-c396-47f9-8534-4cbd934ef09d-000000@email.amazonses.com> (raw)
In-Reply-To: <20190322195926.GB10344@bombadil.infradead.org>

On Fri, 22 Mar 2019, Matthew Wilcox wrote:

> On Fri, Mar 22, 2019 at 07:39:31PM +0000, Christopher Lameter wrote:
> > On Fri, 22 Mar 2019, Waiman Long wrote:
> >
> > > >
> > > >> I am looking forward to it.
> > > > There is also alrady rcu being used in these paths. kfree_rcu() would not
> > > > be enough? It is an estalished mechanism that is mature and well
> > > > understood.
> > > >
> > > In this case, the memory objects are from kmem caches, so they can't
> > > freed using kfree_rcu().
> >
> > Oh they can. kfree() can free memory from any slab cache.
>
> Only for SLAB and SLUB.  SLOB requires that you pass a pointer to the
> slab cache; it has no way to look up the slab cache from the object.

Well then we could either fix SLOB to conform to the others or add a
kmem_cache_free_rcu() variant.


  reply	other threads:[~2019-03-25 14:15 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-21 21:45 [PATCH 0/4] Signal: Fix hard lockup problem in flush_sigqueue() Waiman Long
2019-03-21 21:45 ` [PATCH 1/4] mm: Implement kmem objects freeing queue Waiman Long
2019-03-22 17:47   ` Christopher Lameter
2019-03-21 21:45 ` [PATCH 2/4] signal: Make flush_sigqueue() use free_q to release memory Waiman Long
2019-03-22  1:52   ` Matthew Wilcox
2019-03-22 11:16     ` Oleg Nesterov
2019-03-22 16:10       ` Waiman Long
2019-03-22 17:50         ` Christopher Lameter
2019-03-22 18:12           ` Waiman Long
2019-03-22 19:39             ` Christopher Lameter
2019-03-22 19:59               ` Matthew Wilcox
2019-03-25 14:15                 ` Christopher Lameter [this message]
2019-03-25 15:26                   ` Matthew Wilcox
2019-03-25 16:16                     ` Christopher Lameter
2019-03-26 13:36                   ` Oleg Nesterov
2019-03-26 13:29           ` Oleg Nesterov
2019-03-21 21:45 ` [PATCH 3/4] signal: Add free_uid_to_q() Waiman Long
2019-03-21 21:45 ` [PATCH 4/4] mm: Do periodic rescheduling when freeing objects in kmem_free_up_q() Waiman Long
2019-03-21 22:00   ` Peter Zijlstra
2019-03-22 14:35     ` Waiman Long
2019-03-22 10:15 ` [PATCH 0/4] Signal: Fix hard lockup problem in flush_sigqueue() Matthew Wilcox
2019-03-22 11:49   ` Oleg Nesterov

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