From: Christoph Hellwig <hch@lst.de>
To: Rob Clark <robdclark@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Catalin Marinas <catalin.marinas@arm.com>,
David Airlie <airlied@linux.ie>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Sean Paul <sean@poorly.run>, Rob Clark <robdclark@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Daniel Vetter <daniel@ffwll.ch>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
Allison Randal <allison@lohutok.net>
Subject: Re: [PATCH 1/2] drm: add cache support for arm64
Date: Thu, 8 Aug 2019 09:59:47 +0200 [thread overview]
Message-ID: <20190808075947.GE30308@lst.de> (raw)
In-Reply-To: <CAJs_Fx71T=kJEgt28TWqzw+jOahSbLQynCg83+szQW7op4xBkQ@mail.gmail.com>
On Wed, Aug 07, 2019 at 10:30:04AM -0700, Rob Clark wrote:
> So, we do end up using GFP_HIGHUSER, which appears to get passed thru
> when shmem gets to the point of actually allocating pages.. not sure
> if that just ends up being a hint, or if it guarantees that we don't
> get something in the linear map.
>
> (Bear with me while I "page" this all back in.. last time I dug thru
> the shmem code was probably pre-armv8, or at least before I had any
> armv8 hw)
GFP_HIGHUSER basically just means that this is an allocation that could
dip into highmem, in which case it would not have a kernel mapping.
This can happen on arm + LPAE, but not on arm64.
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Rob Clark <robdclark@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Christoph Hellwig <hch@lst.de>, Rob Clark <robdclark@gmail.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
Allison Randal <allison@lohutok.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] drm: add cache support for arm64
Date: Thu, 8 Aug 2019 09:59:47 +0200 [thread overview]
Message-ID: <20190808075947.GE30308@lst.de> (raw)
In-Reply-To: <CAJs_Fx71T=kJEgt28TWqzw+jOahSbLQynCg83+szQW7op4xBkQ@mail.gmail.com>
On Wed, Aug 07, 2019 at 10:30:04AM -0700, Rob Clark wrote:
> So, we do end up using GFP_HIGHUSER, which appears to get passed thru
> when shmem gets to the point of actually allocating pages.. not sure
> if that just ends up being a hint, or if it guarantees that we don't
> get something in the linear map.
>
> (Bear with me while I "page" this all back in.. last time I dug thru
> the shmem code was probably pre-armv8, or at least before I had any
> armv8 hw)
GFP_HIGHUSER basically just means that this is an allocation that could
dip into highmem, in which case it would not have a kernel mapping.
This can happen on arm + LPAE, but not on arm64.
next prev parent reply other threads:[~2019-08-08 8:00 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-05 21:14 [PATCH 1/2] drm: add cache support for arm64 Rob Clark
2019-08-05 21:14 ` Rob Clark
2019-08-05 21:14 ` [PATCH 2/2] drm/msm: use drm_cache when available Rob Clark
2019-08-05 21:14 ` Rob Clark
2019-08-06 8:48 ` [PATCH 1/2] drm: add cache support for arm64 Christoph Hellwig
2019-08-06 8:48 ` Christoph Hellwig
2019-08-06 9:38 ` Daniel Vetter
2019-08-06 9:38 ` Daniel Vetter
2019-08-06 9:38 ` Daniel Vetter
2019-08-06 11:38 ` Christoph Hellwig
2019-08-06 11:38 ` Christoph Hellwig
2019-08-06 14:11 ` Rob Clark
2019-08-06 14:11 ` Rob Clark
2019-08-06 14:34 ` Mark Rutland
2019-08-06 14:34 ` Mark Rutland
2019-08-06 16:31 ` Rob Clark
2019-08-06 16:31 ` Rob Clark
2019-08-07 12:38 ` Mark Rutland
2019-08-07 12:38 ` Mark Rutland
2019-08-07 16:15 ` Rob Clark
2019-08-07 16:15 ` Rob Clark
2019-08-07 16:49 ` Mark Rutland
2019-08-07 16:49 ` Mark Rutland
2019-08-07 17:30 ` Rob Clark
2019-08-07 17:30 ` Rob Clark
2019-08-08 7:59 ` Christoph Hellwig [this message]
2019-08-08 7:59 ` Christoph Hellwig
2019-08-08 16:44 ` Rob Clark
2019-08-08 16:44 ` Rob Clark
2019-08-09 8:18 ` Christoph Hellwig
2019-08-09 8:18 ` Christoph Hellwig
2019-08-08 7:58 ` Christoph Hellwig
2019-08-08 7:58 ` Christoph Hellwig
2019-08-08 10:20 ` Mark Rutland
2019-08-08 10:20 ` Mark Rutland
2019-08-08 10:24 ` Mark Rutland
2019-08-08 10:24 ` Mark Rutland
2019-08-08 10:32 ` Will Deacon
2019-08-08 10:32 ` Will Deacon
2019-08-08 7:53 ` Christoph Hellwig
2019-08-08 7:53 ` Christoph Hellwig
2019-08-06 15:50 ` Christoph Hellwig
2019-08-06 15:50 ` Christoph Hellwig
2019-08-06 16:23 ` Rob Clark
2019-08-06 16:23 ` Rob Clark
2019-08-06 16:26 ` Rob Clark
2019-08-06 16:26 ` Rob Clark
2019-08-07 6:25 ` Christoph Hellwig
2019-08-07 6:25 ` Christoph Hellwig
2019-08-07 8:48 ` Daniel Vetter
2019-08-07 8:48 ` Daniel Vetter
2019-08-08 9:55 ` Christoph Hellwig
2019-08-08 9:55 ` Christoph Hellwig
2019-08-08 11:58 ` Daniel Vetter
2019-08-08 11:58 ` Daniel Vetter
2019-08-08 11:58 ` Daniel Vetter
2019-08-09 8:14 ` Christoph Hellwig
2019-08-09 8:14 ` Christoph Hellwig
2019-08-07 16:09 ` Rob Clark
2019-08-07 16:09 ` Rob Clark
2019-08-08 10:00 ` Christoph Hellwig
2019-08-08 10:00 ` Christoph Hellwig
2019-08-08 16:32 ` Rob Clark
2019-08-08 16:32 ` Rob Clark
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