From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>,
DRI Development <dri-devel@lists.freedesktop.org>
Cc: "Intel Graphics Development" <intel-gfx@lists.freedesktop.org>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Jon Bloomfield" <jon.bloomfield@intel.com>,
"Chris Wilson" <chris@chris-wilson.co.uk>,
"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
"Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
"Matthew Auld" <matthew.auld@intel.com>,
"Lionel Landwerlin" <lionel.g.landwerlin@intel.com>,
"Dave Airlie" <airlied@redhat.com>,
"Jason Ekstrand" <jason@jlekstrand.net>
Subject: Re: [Intel-gfx] [PATCH 10/11] drm/i915: use xa_lock/unlock for fpriv->vm_xa lookups
Date: Tue, 31 Aug 2021 11:29:55 +0200 [thread overview]
Message-ID: <cfd5c846-fbc5-4d7d-230a-0a1afe3e88de@linux.intel.com> (raw)
In-Reply-To: <20210813203033.3179400-10-daniel.vetter@ffwll.ch>
Op 13-08-2021 om 22:30 schreef Daniel Vetter:
> We don't need the absolute speed of rcu for this. And
> i915_address_space in general dont need rcu protection anywhere else,
> after we've made gem contexts and engines a lot more immutable.
>
> Note that this semantically reverts
>
> commit aabbe344dc3ca5f7d8263a02608ba6179e8a4499
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date: Fri Aug 30 19:03:25 2019 +0100
>
> drm/i915: Use RCU for unlocked vm_idr lookup
>
> except we have the conversion from idr to xarray in between.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Jon Bloomfield <jon.bloomfield@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
> Cc: Matthew Auld <matthew.auld@intel.com>
> Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Jason Ekstrand <jason@jlekstrand.net>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 005b1cec7007..e37fac8fac0c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1881,11 +1881,11 @@ i915_gem_vm_lookup(struct drm_i915_file_private *file_priv, u32 id)
> {
> struct i915_address_space *vm;
>
> - rcu_read_lock();
> + xa_lock(&file_priv->vm_xa);
> vm = xa_load(&file_priv->vm_xa, id);
> if (vm && !kref_get_unless_zero(&vm->ref))
> vm = NULL;
I think this could be a plain i915_vm_get now, kref_get_unless_zero is not guarded by RCU any more.
> - rcu_read_unlock();
> + xa_unlock(&file_priv->vm_xa);
>
> return vm;
> }
Apart from that, all looks good.
With this fix, for patch 2-11:
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
next prev parent reply other threads:[~2021-08-31 9:29 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 20:30 [Intel-gfx] [PATCH 01/11] drm/i915: Release i915_gem_context from a worker Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 02/11] drm/i915: Release ctx->syncobj on final put, not on ctx close Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 03/11] drm/i915: Keep gem ctx->vm alive until the final put Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 04/11] drm/i915: Drop code to handle set-vm races from execbuf Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 05/11] drm/i915: Rename i915_gem_context_get_vm_rcu to i915_gem_context_get_eb_vm Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 06/11] drm/i915: Use i915_gem_context_get_eb_vm in ctx_getparam Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 07/11] drm/i915: Add i915_gem_context_is_full_ppgtt Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 08/11] drm/i915: Use i915_gem_context_get_eb_vm in intel_context_set_gem Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 09/11] drm/i915: Drop __rcu from gem_context->vm Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 10/11] drm/i915: use xa_lock/unlock for fpriv->vm_xa lookups Daniel Vetter
2021-08-31 9:29 ` Maarten Lankhorst [this message]
2021-08-31 12:14 ` [Intel-gfx] [PATCH] " Daniel Vetter
2021-08-13 20:30 ` [Intel-gfx] [PATCH 11/11] drm/i915: Stop rcu support for i915_address_space Daniel Vetter
2021-08-13 21:48 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/11] drm/i915: Release i915_gem_context from a worker Patchwork
2021-08-13 21:49 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-08-13 22:18 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-08-14 1:26 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-08-14 10:43 ` [Intel-gfx] [PATCH] " Daniel Vetter
2021-08-31 9:38 ` Maarten Lankhorst
2021-08-31 12:16 ` Daniel Vetter
2021-08-31 15:14 ` Daniel Vetter
2021-09-02 10:04 ` Maarten Lankhorst
2021-08-14 10:55 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with drm/i915: Release i915_gem_context from a worker (rev2) Patchwork
2021-08-14 10:56 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-08-14 11:19 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-08-14 12:38 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2021-08-31 10:16 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with drm/i915: Release i915_gem_context from a worker (rev3) Patchwork
2021-08-31 12:18 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with drm/i915: Release i915_gem_context from a worker (rev4) Patchwork
2021-09-02 12:42 ` [Intel-gfx] [PATCH 01/11] drm/i915: Release i915_gem_context from a worker Tvrtko Ursulin
2021-09-02 15:05 ` Daniel Vetter
2021-09-02 16:20 ` Tvrtko Ursulin
2021-09-02 20:02 ` Daniel Vetter
2021-09-03 10:40 ` Tvrtko Ursulin
2021-09-02 14:20 Daniel Vetter
2021-09-02 14:20 ` [Intel-gfx] [PATCH 10/11] drm/i915: use xa_lock/unlock for fpriv->vm_xa lookups Daniel Vetter
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