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From: Sumitra Sharma <sumitraartsy@gmail.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org
Cc: Ira Weiny <ira.weiny@intel.com>, Fabio <fmdefrancesco@gmail.com>,
	Deepak R Varma <drv@mailo.com>,
	Sumitra Sharma <sumitraartsy@gmail.com>
Subject: [PATCH v2] drm/i915: Replace kmap() with kmap_local_page()
Date: Sat, 17 Jun 2023 11:04:20 -0700	[thread overview]
Message-ID: <20230617180420.GA410966@sumitra.com> (raw)

kmap() has been deprecated in favor of the kmap_local_page()
due to high cost, restricted mapping space, the overhead of a
global lock for synchronization, and making the process sleep
in the absence of free slots.

kmap_local_page() is faster than kmap() and offers thread-local
and CPU-local mappings, take pagefaults in a local kmap region
and preserves preemption by saving the mappings of outgoing tasks
and restoring those of the incoming one during a context switch.

The mapping is kept thread local in the function
“i915_vma_coredump_create” in i915_gpu_error.c

Therefore, replace kmap() with kmap_local_page().

Suggested-by: Ira Weiny <ira.weiny@intel.com>

Signed-off-by: Sumitra Sharma <sumitraartsy@gmail.com>
---

Changes in v2:
	- Replace kmap() with kmap_local_page().
	- Change commit subject and message.

 drivers/gpu/drm/i915/i915_gpu_error.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index f020c0086fbc..bc41500eedf5 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1164,9 +1164,9 @@ i915_vma_coredump_create(const struct intel_gt *gt,
 
 			drm_clflush_pages(&page, 1);
 
-			s = kmap(page);
+			s = kmap_local_page(page);
 			ret = compress_page(compress, s, dst, false);
-			kunmap(page);
+			kunmap_local(s);
 
 			drm_clflush_pages(&page, 1);
 
-- 
2.25.1


             reply	other threads:[~2023-06-17 18:04 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-17 18:04 Sumitra Sharma [this message]
2023-06-18 18:11 ` [PATCH v2] drm/i915: Replace kmap() with kmap_local_page() Ira Weiny
2023-06-19  7:59   ` Thomas Hellström (Intel)
2023-06-19  8:44     ` Tvrtko Ursulin
2023-06-19 15:45   ` Sumitra Sharma
2023-06-20 13:23     ` Ira Weiny
2023-06-20 18:07       ` Sumitra Sharma
2023-06-21  9:06         ` Thomas Hellström (Intel)
2023-06-21 13:24           ` Fabio M. De Francesco
2023-06-21 16:35           ` Ira Weiny
2023-06-21 18:51             ` Thomas Hellström (Intel)
2023-06-22  9:40               ` Tvrtko Ursulin
2023-06-26  9:02       ` Tvrtko Ursulin
2023-06-24  0:10 ` Fabio M. De Francesco
  -- strict thread matches above, loose matches on Subject: below --
2021-12-10 23:23 [PATCH 1/7] " ira.weiny
2021-12-22  6:08 ` [PATCH V2] " ira.weiny

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