From: Christoph Hellwig <hch@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
pratikp@codeaurora.org, pdaly@codeaurora.org,
sudraja@codeaurora.org, iamjoonsoo.kim@lge.com,
linux-arm-msm-owner@vger.kernel.org,
Vinayak Menon <vinmenon@codeaurora.org>,
linux-kernel-owner@vger.kernel.org
Subject: Re: [PATCH v2] mm: cma: indefinitely retry allocations in cma_alloc
Date: Mon, 28 Sep 2020 08:39:07 +0100 [thread overview]
Message-ID: <20200928073907.GA29322@infradead.org> (raw)
In-Reply-To: <a3d62a77-4c4f-e86c-de6d-5222c2a747e0@redhat.com>
On Tue, Sep 15, 2020 at 09:53:30AM +0200, David Hildenbrand wrote:
> Two thoughts:
>
> 1. Most (all?) alloc_contig_range() users are interested in handling
> short-term pinnings in a nice way (IOW, make the allocation succeed).
> I'd much rather want to see this being handled in a nice fashion inside
> alloc_contig_range() than having to encode endless loops in the caller.
> This means I strongly prefer something like [3] if feasible. But I can
> understand that stuff ([5]) is complicated. I have to admit that I am
> not an expert on the short term pinning described by you, and how to
> eventually fix it.
Agreed. Also retrying forever is simply broken, and will lead to
deadlocks for the DMA calls into CMA, so with my dma-mapping hat on
I have to hard-NAK this approach.
prev parent reply other threads:[~2020-09-28 7:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <06489716814387e7f147cf53d1b185a8@codeaurora.org>
2020-09-11 19:17 ` [PATCH v2] cma_alloc(), indefinitely retry allocations for -EBUSY failures Chris Goldsworthy
[not found] ` <1599851809-4342-1-git-send-email-cgoldswo@codeaurora.org>
2020-09-11 19:17 ` [PATCH v2] mm: cma: indefinitely retry allocations in cma_alloc Chris Goldsworthy
2020-09-14 9:31 ` David Hildenbrand
2020-09-14 18:33 ` Chris Goldsworthy
2020-09-14 21:52 ` Chris Goldsworthy
2020-09-15 7:53 ` David Hildenbrand
2020-09-17 17:26 ` Chris Goldsworthy
2020-09-17 17:54 ` Chris Goldsworthy
2020-09-24 5:13 ` Chris Goldsworthy
2020-09-28 7:39 ` Christoph Hellwig [this message]
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