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From: David Sterba <dsterba@suse.cz>
To: Christoph Hellwig <hch@infradead.org>
Cc: David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org, vbabka@suse.cz, linux-mm@kvack.org
Subject: Re: [PATCH] btrfs: disable slab merging in debug build
Date: Thu, 13 Jul 2023 14:03:03 +0200	[thread overview]
Message-ID: <20230713120303.GT30916@twin.jikos.cz> (raw)
In-Reply-To: <ZK/eJlk0jb1F4E2V@infradead.org>

On Thu, Jul 13, 2023 at 04:21:10AM -0700, Christoph Hellwig wrote:
> On Wed, Jul 12, 2023 at 09:17:12PM +0200, David Sterba wrote:
> > The slab allocator newly allows to disable merging per-slab (since
> > commit d0bf7d5759c1 ("mm/slab: introduce kmem_cache flag
> > SLAB_NO_MERGE")). Set this for all caches in debug build so we can
> > verify there are no leaks when module gets reloaded.
> 
> So we're having a discussion on linux-mm wether to just disbale slab
> merging by default, because it really is a pain.  Maybe wait for that
> to settle before adding per-subsystem hacks for what really is a slab
> problem?

Yeah I can wait with the patch. That slab merging is considered bad is
new. I remember discussions where Linus and (maybe?) xfs guys argued
pro/against merging of slabs, where xfs wanted not-merging and had to
resort to hacks like empty slab constructor that would prevent it. I
can't find the link but that's base of my reasoning to add a flag
assuming that merging makes sense by default.


  reply	other threads:[~2023-07-13 12:09 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-12 19:17 David Sterba
2023-07-13  7:38 ` Vlastimil Babka
2023-07-13 11:21 ` Christoph Hellwig
2023-07-13 12:03   ` David Sterba [this message]
2023-07-13 12:52     ` Vlastimil Babka

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