From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
x86@kernel.org, xen-devel@lists.xenproject.org,
linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, linux-mm@kvack.org
Subject: Re: [PATCH 3/6] drm/i915: use vmap in shmem_pin_map
Date: Tue, 22 Sep 2020 12:21:44 +0100 [thread overview]
Message-ID: <20200922112144.GB32101@casper.infradead.org> (raw)
In-Reply-To: <20200922062249.GA30831@lst.de>
On Tue, Sep 22, 2020 at 08:22:49AM +0200, Christoph Hellwig wrote:
> On Mon, Sep 21, 2020 at 08:11:57PM +0100, Matthew Wilcox wrote:
> > This is awkward. I'd like it if we had a vfree() variant which called
> > put_page() instead of __free_pages(). I'd like it even more if we
> > used release_pages() instead of our own loop that called put_page().
>
> Note that we don't need a new vfree variant, we can do this manually if
> we want, take a look at kernel/dma/remap.c. But I thought this code
> intentionally doesn't want to do that to avoid locking in the memory
> for the pages array. Maybe the i915 maintainers can clarify.
Actually, vfree() will work today; I cc'd you on a documentation update
to make it clear that this is permitted.
From my current experience with the i915 shmem code, I think that the
i915 maintainers are experts at graphics, and are unfamiliar with the MM.
There are a number of places where they do things the hard way.
next prev parent reply other threads:[~2020-09-22 11:22 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 16:37 remove alloc_vm_area Christoph Hellwig
2020-09-18 16:37 ` [PATCH 1/6] zsmalloc: switch from alloc_vm_area to get_vm_area Christoph Hellwig
2020-09-21 17:42 ` Minchan Kim
2020-09-21 18:17 ` Christoph Hellwig
2020-09-21 18:42 ` Minchan Kim
2020-09-21 18:43 ` Christoph Hellwig
2020-09-18 16:37 ` [PATCH 2/6] mm: add a vmap_pfn function Christoph Hellwig
2020-09-18 16:37 ` [PATCH 3/6] drm/i915: use vmap in shmem_pin_map Christoph Hellwig
2020-09-21 19:11 ` Matthew Wilcox
2020-09-22 6:22 ` Christoph Hellwig
2020-09-22 8:23 ` [Intel-gfx] " Tvrtko Ursulin
2020-09-22 14:31 ` Christoph Hellwig
2020-09-22 16:13 ` Tvrtko Ursulin
2020-09-22 16:33 ` Christoph Hellwig
2020-09-22 17:04 ` Tvrtko Ursulin
2020-09-23 6:11 ` Christoph Hellwig
2020-09-22 11:21 ` Matthew Wilcox [this message]
2020-09-22 14:39 ` Christoph Hellwig
2020-09-22 14:53 ` Matthew Wilcox
2020-09-18 16:37 ` [PATCH 4/6] drm/i915: use vmap in i915_gem_object_map Christoph Hellwig
2020-09-23 9:52 ` [Intel-gfx] " Tvrtko Ursulin
2020-09-23 13:41 ` Christoph Hellwig
2020-09-23 13:58 ` Tvrtko Ursulin
2020-09-23 14:44 ` Christoph Hellwig
2020-09-24 12:22 ` Tvrtko Ursulin
2020-09-24 13:23 ` Christoph Hellwig
2020-09-18 16:37 ` [PATCH 5/6] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv Christoph Hellwig
2020-09-18 16:37 ` [PATCH 6/6] x86/xen: open code alloc_vm_area in arch_gnttab_valloc Christoph Hellwig
2020-09-21 20:44 ` boris.ostrovsky
2020-09-22 14:58 ` Christoph Hellwig
2020-09-22 15:24 ` boris.ostrovsky
2020-09-22 15:27 ` Christoph Hellwig
2020-09-22 15:34 ` boris.ostrovsky
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