Messages in this thread | | | Date | Wed, 30 Jun 2010 20:55:09 +0900 | Subject | Re: [PATCH 1/2] block: fix leaks associated with discard request payload | From | FUJITA Tomonori <> |
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On Mon, 28 Jun 2010 17:25:36 +0200 Christoph Hellwig <hch@lst.de> wrote:
> On Mon, Jun 28, 2010 at 05:14:28PM +0900, FUJITA Tomonori wrote: > > > While I see the problems with leaking ressources in that case I still > > > can't quite explain the hang I see. > > > > Any way to reproduce the hang without ssd drives? > > Actually the SSDs don't fully hang, they just causes lots of I/O errors > and hit the error handler hard. The hard hang is when running under > qemu. Apply the patch below, then create an if=scsi drive that resides > on an XFS filesystem, and you'll have scsi TP support in the guest:
Ok, I figured out what's wrong.
As I suspected, it's due to the partial completion.
qemu scsi driver tells that the WRITE_SAME command was successful but somehow the command has resid. So we retry it again and again (and leak some memory).
I don't know yet why qemu scsi driver is broken. Maybe there is a bug in it or converting discard to FS sends broken commands to the driver.
I'll try to figure out it tomorrow.
I've put a patch to complete discard command in the all-or-nothing manner:
git://git.kernel.org/pub/scm/linux/kernel/git/tomo/linux-2.6-misc.git discard
At least, the guest kernel doesn't hang for me.
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