linux-kernel - [PATCH v4 6/6] drm/drm-file: Show finer-grained BO sizes in drm_show_memory

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Message-ID: <20230912084044.955864-7-adrian.larumbe@collabora.com>
Date:   Tue, 12 Sep 2023 09:37:00 +0100
From:   Adrián Larumbe <adrian.larumbe@...labora.com>
To:     maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        tzimmermann@...e.de, airlied@...il.com, daniel@...ll.ch,
        robdclark@...il.com, quic_abhinavk@...cinc.com,
        dmitry.baryshkov@...aro.org, sean@...rly.run,
        marijn.suijten@...ainline.org, robh@...nel.org,
        steven.price@....com
Cc:     adrian.larumbe@...labora.com, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, healych@...zon.com,
        kernel@...labora.com
Subject: [PATCH v4 6/6] drm/drm-file: Show finer-grained BO sizes in drm_show_memory_stats

The current implementation will try to pick the highest available size
display unit as soon as the BO size exceeds that of the previous
multiplier. That can lead to loss of precision in BO's whose size is
not a multiple of a MiB.

Fix it by changing the unit selection criteria.

For much bigger BO's, their size will naturally be aligned on something
bigger than a 4 KiB page, so in practice it is very unlikely their display
unit would default to KiB.

Signed-off-by: Adrián Larumbe <adrian.larumbe@...labora.com>
---
 drivers/gpu/drm/drm_file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 762965e3d503..bf7d2fe46bfa 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -879,7 +879,7 @@ static void print_size(struct drm_printer *p, const char *stat,
 	unsigned u;
 
 	for (u = 0; u < ARRAY_SIZE(units) - 1; u++) {
-		if (sz < SZ_1K)
+		if (sz & (SZ_1K - 1))
 			break;
 		sz = div_u64(sz, SZ_1K);
 	}
-- 
2.42.0