From: Christoph Hellwig <hch@infradead.org>
To: Alistair Popple <apopple@nvidia.com>
Cc: linux-mm@kvack.org, nouveau@lists.freedesktop.org,
bskeggs@redhat.com, akpm@linux-foundation.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm-ppc@vger.kernel.org, dri-devel@lists.freedesktop.org,
jhubbard@nvidia.com, rcampbell@nvidia.com, jglisse@redhat.com,
jgg@nvidia.com, hch@infradead.org, daniel@ffwll.ch,
willy@infradead.org
Subject: Re: [PATCH v6 8/8] nouveau/svm: Implement atomic SVM access
Date: Mon, 15 Mar 2021 07:51:13 +0000 [thread overview]
Message-ID: <20210315075113.GD4136862@infradead.org> (raw)
In-Reply-To: <20210312083851.15981-9-apopple@nvidia.com>
> - /*XXX: atomic? */
> - return (fa->access == 0 || fa->access == 3) -
> - (fb->access == 0 || fb->access == 3);
> + /* Atomic access (2) has highest priority */
> + return (-1*(fa->access == 2) + (fa->access == 0 || fa->access == 3)) -
> + (-1*(fb->access == 2) + (fb->access == 0 || fb->access == 3));
This looks really unreabable. If the magic values 0, 2 and 3 had names
it might become a little more understadable, then factor the duplicated
calculation of the priority value into a helper and we'll have code that
mere humans can understand..
> + mutex_lock(&svmm->mutex);
> + if (mmu_interval_read_retry(¬ifier->notifier,
> + notifier_seq)) {
> + mutex_unlock(&svmm->mutex);
> + continue;
> + }
> + break;
> + }
This looks good, why not:
mutex_lock(&svmm->mutex);
if (!mmu_interval_read_retry(¬ifier->notifier,
notifier_seq))
break;
mutex_unlock(&svmm->mutex);
}
next prev parent reply other threads:[~2021-03-15 7:53 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 8:38 [PATCH v6 0/8] Add support for SVM atomics in Nouveau Alistair Popple
2021-03-12 8:38 ` [PATCH v6 1/8] mm: Remove special swap entry functions Alistair Popple
2021-03-15 7:27 ` Christoph Hellwig
2021-03-22 9:20 ` Alistair Popple
2021-03-12 8:38 ` [PATCH v6 2/8] mm/swapops: Rework swap entry manipulation code Alistair Popple
2021-03-12 8:38 ` [PATCH v6 3/8] mm/rmap: Split try_to_munlock from try_to_unmap Alistair Popple
2021-03-15 7:28 ` Christoph Hellwig
2021-03-12 8:38 ` [PATCH v6 4/8] mm/rmap: Split migration into its own function Alistair Popple
2021-03-12 8:38 ` [PATCH v6 5/8] mm: Device exclusive memory access Alistair Popple
2021-03-15 7:42 ` Christoph Hellwig
2021-03-22 10:27 ` Alistair Popple
2021-03-12 8:38 ` [PATCH v6 6/8] mm: Selftests for exclusive device memory Alistair Popple
2021-03-12 8:38 ` [PATCH v6 7/8] nouveau/svm: Refactor nouveau_range_fault Alistair Popple
2021-03-12 8:38 ` [PATCH v6 8/8] nouveau/svm: Implement atomic SVM access Alistair Popple
2021-03-15 7:51 ` Christoph Hellwig [this message]
2021-03-22 9:27 ` Alistair Popple
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