nvme: provide fallback for discard alloc failure

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When boxes are run near (or to) OOM, we have a problem with the discard
page allocation in nvme. If we fail allocating the special page, we
return busy, and it'll get retried. But since ordering is honored for
dispatch requests, we can keep retrying this same IO and failing. Behind
that IO could be requests that want to free memory, but they never get
the chance.

Allocate a fixed discard page per controller for a safe fallback, and use
that if the initial allocation fails.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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Jens Axboe 2018-12-12 09:18:11 -07:00 • committed by Christoph Hellwig

parent 8eb5d89f48

commit cb5b7262b0

2 changed files with 38 additions and 6 deletions

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41

drivers/nvme/host/core.c

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3

drivers/nvme/host/nvme.h

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