From: Christoph Hellwig <hch@infradead.org>
To: Jeff Layton <jlayton@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-xfs@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH] xfs: Do not free xfs_extent_busy from inside a spinlock
Date: Tue, 23 Jul 2019 10:08:43 -0700 [thread overview]
Message-ID: <20190723170843.GA1952@infradead.org> (raw)
In-Reply-To: <c2f3542bd06860ecf33f1785b9c146a09a155bf7.camel@kernel.org>
On Tue, Jul 23, 2019 at 01:07:00PM -0400, Jeff Layton wrote:
> Note that those places are already broken. AIUI, the basic issue is that
> vmalloc/vfree have to fix up page tables and that requires being able to
> sleep. This patch just makes this situation more evident. If that patch
> gets merged, I imagine we'll have a lot of places to clean up (not just
> in xfs).
>
> Anyway, in the case of being in an interrupt, we currently queue the
> freeing to a workqueue. Al mentioned that we could create a new
> kvfree_atomic that we could use from atomic contexts like this. That may
> be another option (though Carlos' patch looked reasonable to me and
> would probably be more efficient).
The point is for XFS we generally only use kmem_free for pure kmalloc
allocations under spinlocks. But yes, the interfac is a little
suboptimal and a kmem_free_large would be nicer and then warnings like
this that might be pretty useful could be added.
next prev parent reply other threads:[~2019-07-23 17:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 15:00 [PATCH] xfs: Do not free xfs_extent_busy from inside a spinlock Carlos Maiolino
2019-07-23 15:11 ` Darrick J. Wong
2019-07-23 15:31 ` Carlos Maiolino
2019-07-23 15:51 ` Christoph Hellwig
2019-07-23 17:07 ` Jeff Layton
2019-07-23 17:08 ` Christoph Hellwig [this message]
2019-07-23 17:38 ` Jeff Layton
2019-07-23 17:41 ` Christoph Hellwig
2019-07-23 15:13 ` Carlos Maiolino
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