From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 554E02E8B9B; Fri, 24 Apr 2026 15:19:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777043962; cv=none; b=YkDGRrDHQUzpS1ofPh+pdtmg9Gb4ca4LMaTo8flAAKNbtYPXkAfOZAddntCyAjNlvrDmS2UxVGo4pJuSMuRlBLKesgxvqN6JCtrHC3EhRLBvggi04d7tf/27oHEUet8ynLqTiJn2mUh+K4YZNNkFJ3wrNhZwiCUBFr5O6ekGVlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777043962; c=relaxed/simple; bh=cEi4t4R7z5qw7S83+FnxUKjQs4TGfmgaCpSsRrd+oWg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Vau0cUKmJdxrsnr4R/uzUl4LeNtGF1ThKoPiutkN6+EekECP7f6E2d80j0nEmWAqj095wS114K7Q1eDepbfp92ee/oPtAkqrRnfZD4dDggDbML5j19QN35IscAQPgsL5Z+LZ7NFR/isQh9WaYiVY5mzezcWMTGclblOV70USJLY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=e6Kq0Vb6; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="e6Kq0Vb6" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 608B4358A; Fri, 24 Apr 2026 08:19:07 -0700 (PDT) Received: from [10.1.26.15] (e122027.cambridge.arm.com [10.1.26.15]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 57D733F7B4; Fri, 24 Apr 2026 08:19:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777043952; bh=cEi4t4R7z5qw7S83+FnxUKjQs4TGfmgaCpSsRrd+oWg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=e6Kq0Vb6k+R0Yqtpabc6n8T2gQya3cHrC8F4K3qrqnW9RLg9750Z9Skd5hsfL/L4f P7XMVWG54EFWNhgQw8SKanLkpB88MkYN8BdG4TmbqcLEZpOOfGW/xIltJT3qrneJwO wRWCx66HHiLghfcYnARi95AnXovVArijMz0fo7Ig= Message-ID: <145ed843-37c9-45cd-8f07-604d03fdc5df@arm.com> Date: Fri, 24 Apr 2026 16:19:06 +0100 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/3] drm/panthor: Implement evicted status for GEM objects To: Nicolas Frattaroli , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Boris Brezillon , Liviu Dudau , Jonathan Corbet , Shuah Khan Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, linux-doc@vger.kernel.org References: <20260423-panthor-bo-reclaim-observability-v3-0-60af32164a4f@collabora.com> <20260423-panthor-bo-reclaim-observability-v3-2-60af32164a4f@collabora.com> From: Steven Price Content-Language: en-GB In-Reply-To: <20260423-panthor-bo-reclaim-observability-v3-2-60af32164a4f@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 23/04/2026 13:33, Nicolas Frattaroli wrote: > For fdinfo to be able to fill its evicted counter with data, panthor > needs to keep track of whether a GEM object has ever been reclaimed. > Just checking whether the pages are resident isn't enough, as newly > allocated objects also won't be resident. > > Do this with a new atomic_t member on panthor_gem_object. It's increased > when an object gets evicted by the shrinker, and saturates at INT_MAX. > This means that once an object has been evicted at least once, its > reclaim counter will never return to 0. > > Due to this, it's possible to distinguish evicted non-resident pages > from newly allocated non-resident pages by checking whether > reclaimed_count is != 0 > > Use this new member to then set the appropriate DRM_GEM_OBJECT_EVICTED > status flag for fdinfo. > > Also add a new column and status flag to the panthor gems debugfs: the > column is the number of times an object has been evicted, whereas the > flag indicates whether it currently is evicted. > > Signed-off-by: Nicolas Frattaroli Reviewed-by: Steven Price > --- > drivers/gpu/drm/panthor/panthor_gem.c | 18 ++++++++++++++---- > drivers/gpu/drm/panthor/panthor_gem.h | 10 ++++++++++ > 2 files changed, 24 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c > index 69cef05b6ef7..b6fe20b7e6d0 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -687,6 +687,8 @@ static void panthor_gem_evict_locked(struct panthor_gem_object *bo) > if (drm_WARN_ON_ONCE(bo->base.dev, !bo->backing.pages)) > return; > > + atomic_add_unless(&bo->reclaimed_count, 1, INT_MAX); > + > panthor_gem_dev_map_cleanup_locked(bo); > panthor_gem_backing_cleanup_locked(bo); > panthor_gem_update_reclaim_state_locked(bo, NULL); > @@ -788,6 +790,8 @@ static enum drm_gem_object_status panthor_gem_status(struct drm_gem_object *obj) > > if (drm_gem_is_imported(&bo->base) || bo->backing.pages) > res |= DRM_GEM_OBJECT_RESIDENT; > + else if (atomic_read(&bo->reclaimed_count)) > + res |= DRM_GEM_OBJECT_EVICTED; > > return res; > } > @@ -1595,6 +1599,7 @@ static void panthor_gem_debugfs_print_flag_names(struct seq_file *m) > static const char * const gem_state_flags_names[] = { > [PANTHOR_DEBUGFS_GEM_STATE_IMPORTED_BIT] = "imported", > [PANTHOR_DEBUGFS_GEM_STATE_EXPORTED_BIT] = "exported", > + [PANTHOR_DEBUGFS_GEM_STATE_EVICTED_BIT] = "evicted", > }; > > static const char * const gem_usage_flags_names[] = { > @@ -1625,6 +1630,7 @@ static void panthor_gem_debugfs_bo_print(struct panthor_gem_object *bo, > { > enum panthor_gem_reclaim_state reclaim_state = bo->reclaim_state; > unsigned int refcount = kref_read(&bo->base.refcount); > + int reclaimed_count = atomic_read(&bo->reclaimed_count); > char creator_info[32] = {}; > size_t resident_size; > u32 gem_usage_flags = bo->debugfs.flags; > @@ -1638,16 +1644,20 @@ static void panthor_gem_debugfs_bo_print(struct panthor_gem_object *bo, > > snprintf(creator_info, sizeof(creator_info), > "%s/%d", bo->debugfs.creator.process_name, bo->debugfs.creator.tgid); > - seq_printf(m, "%-32s%-16d%-16d%-16zd%-16zd0x%-16lx", > + seq_printf(m, "%-32s%-16d%-16d%-11d%-16zd%-16zd0x%-16lx", > creator_info, > bo->base.name, > refcount, > + reclaimed_count, > bo->base.size, > resident_size, > drm_vma_node_start(&bo->base.vma_node)); > > if (drm_gem_is_imported(&bo->base)) > gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED; > + else if (!resident_size && reclaimed_count) > + gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_EVICTED; > + > if (bo->base.dma_buf) > gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED; > > @@ -1671,8 +1681,8 @@ static void panthor_gem_debugfs_print_bos(struct panthor_device *ptdev, > > panthor_gem_debugfs_print_flag_names(m); > > - seq_puts(m, "created-by global-name refcount size resident-size file-offset state usage label\n"); > - seq_puts(m, "----------------------------------------------------------------------------------------------------------------------------------------------\n"); > + seq_puts(m, "created-by global-name refcount evictions size resident-size file-offset state usage label\n"); > + seq_puts(m, "---------------------------------------------------------------------------------------------------------------------------------------------------------\n"); > > scoped_guard(mutex, &ptdev->gems.lock) { > list_for_each_entry(bo, &ptdev->gems.node, debugfs.node) { > @@ -1680,7 +1690,7 @@ static void panthor_gem_debugfs_print_bos(struct panthor_device *ptdev, > } > } > > - seq_puts(m, "==============================================================================================================================================\n"); > + seq_puts(m, "=========================================================================================================================================================\n"); > seq_printf(m, "Total size: %zd, Total resident: %zd, Total reclaimable: %zd\n", > totals.size, totals.resident, totals.reclaimable); > } > diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h > index ae0491d0b121..56d63137b4eb 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.h > +++ b/drivers/gpu/drm/panthor/panthor_gem.h > @@ -19,12 +19,16 @@ struct panthor_vm; > enum panthor_debugfs_gem_state_flags { > PANTHOR_DEBUGFS_GEM_STATE_IMPORTED_BIT = 0, > PANTHOR_DEBUGFS_GEM_STATE_EXPORTED_BIT = 1, > + PANTHOR_DEBUGFS_GEM_STATE_EVICTED_BIT = 2, > > /** @PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED: GEM BO is PRIME imported. */ > PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED = BIT(PANTHOR_DEBUGFS_GEM_STATE_IMPORTED_BIT), > > /** @PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED: GEM BO is PRIME exported. */ > PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED = BIT(PANTHOR_DEBUGFS_GEM_STATE_EXPORTED_BIT), > + > + /** @PANTHOR_DEBUGFS_GEM_STATE_FLAG_EVICTED: GEM BO is evicted to swap. */ > + PANTHOR_DEBUGFS_GEM_STATE_FLAG_EVICTED = BIT(PANTHOR_DEBUGFS_GEM_STATE_EVICTED_BIT), > }; > > enum panthor_debugfs_gem_usage_flags { > @@ -172,6 +176,12 @@ struct panthor_gem_object { > /** @reclaim_state: Cached reclaim state */ > enum panthor_gem_reclaim_state reclaim_state; > > + /** > + * @reclaimed_count: How many times object has been evicted to swap. > + * The count saturates at %INT_MAX and will never wrap around to 0. > + */ > + atomic_t reclaimed_count; > + > /** > * @exclusive_vm_root_gem: Root GEM of the exclusive VM this GEM object > * is attached to. >