From: Thomas Hellstrom <thellstrom@vmware.com>
To: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: airlied@gmail.com, airlied@redhat.com,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 4/4] drm/ttm: Optimize reservation slightly
Date: Mon, 05 Nov 2012 15:09:26 +0100 [thread overview]
Message-ID: <5097C896.80805@vmware.com> (raw)
In-Reply-To: <5097C6A1.9000405@canonical.com>
On 11/05/2012 03:01 PM, Maarten Lankhorst wrote:
> Hey,
>
> Op 05-11-12 14:31, Thomas Hellstrom schreef:
>> Reservation locking currently always takes place under the LRU spinlock.
>> Hence, strictly there is no need for an atomic_cmpxchg call; we can use
>> atomic_read followed by atomic_write since nobody else will ever reserve
>> without the lru spinlock held.
>> At least on Intel this should remove a locked bus cycle on successful
>> reserve.
>>
>> Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
>>
> Is that really a good thing to submit when I am busy killing lru lock around reserve? :-)
>
If your patch series makes it into the same kernel, let's kill this
patch. Otherwise it may live
at least for a kernel release. It's not a big thing to rebase against,
and I won't complain if your
patch adds another atomic read-modify-write op here. :)
/Thomas
next prev parent reply other threads:[~2012-11-05 14:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-05 13:31 [PATCH 0/4] drm/ttm: Get rid of a number of atomic read-modify-write ops Thomas Hellstrom
2012-11-05 13:31 ` [PATCH 1/4] drm: Make hashtab rcu-safe Thomas Hellstrom
2012-11-05 13:31 ` [PATCH 2/4] kref: Implement kref_get_unless_zero Thomas Hellstrom
2012-11-05 13:31 ` [PATCH 3/4] drm/ttm, drm/vmwgfx: Use RCU locking for object lookups Thomas Hellstrom
2012-11-05 13:34 ` Thomas Hellstrom
2012-11-05 13:31 ` [PATCH 4/4] drm/ttm: Optimize reservation slightly Thomas Hellstrom
2012-11-05 14:01 ` Maarten Lankhorst
2012-11-05 14:09 ` Thomas Hellstrom [this message]
-- strict thread matches above, loose matches on Subject: below --
2012-11-05 13:55 [PATCH 0/4] drm/ttm: Get rid of a number of atomic read-modify-write ops v2 Thomas Hellstrom
2012-11-05 13:55 ` [PATCH 4/4] drm/ttm: Optimize reservation slightly Thomas Hellstrom
2012-11-06 11:31 [PATCH 0/4] drm/ttm: Get rid of a number of atomic read-modify-write ops v3 Thomas Hellstrom
2012-11-06 11:31 ` [PATCH 4/4] drm/ttm: Optimize reservation slightly Thomas Hellstrom
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