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Message-ID: <8cb69f245311a348164b0b5ca3dbc59386746035.1712520052.git.christophe.jaillet@wanadoo.fr>
Date: Sun, 7 Apr 2024 22:01:49 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: "Rafael J. Wysocki" <rafael@...nel.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Zhang Rui <rui.zhang@...el.com>,
Lukasz Luba <lukasz.luba@....com>,
Matthias Brugger <matthias.bgg@...il.com>,
AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Cc: linux-kernel@...r.kernel.org,
kernel-janitors@...r.kernel.org,
Christophe JAILLET <christophe.jaillet@...adoo.fr>,
linux-pm@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org
Subject: [PATCH 2/2] thermal/drivers/mediatek/lvts_thermal: Improve some memory allocation
lvts_debugfs_init() is called with lvts_td->num_lvts_ctrl being 2, 3 or 4.
sizeof(struct debugfs_regset32) is small. 32 byres on a x86_64.
So, given the overhead of devm_kzalloc(), it is better to allocate all
needed regset at once.
The overhead of devm_kzalloc() is 40 bytes on a x86_64, and because of
rounding in memory allocation, it leads to:
2 * (32 + 40) = 2 * 72 --> 2 96 bytes allocations for a total of 192 bytes
3 * (32 + 40) = 3 * 72 --> 3 96 bytes allocations for a total of 288 bytes
4 * (32 + 40) = 4 * 72 --> 4 96 bytes allocations for a total of 384 bytes
using a single devm_kcalloc():
2 * 32 + 40 = 104 --> 1 allocation for a total of 128
3 * 32 + 40 = 136 --> 1 allocation for a total of 192
4 * 32 + 40 = 168 --> 1 allocation for a total of 192
So, this saves both a few bytes and reduce memory fragmentation.
Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
Compile tested-only
---
drivers/thermal/mediatek/lvts_thermal.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
index 3003dc350766..b133f731c5ba 100644
--- a/drivers/thermal/mediatek/lvts_thermal.c
+++ b/drivers/thermal/mediatek/lvts_thermal.c
@@ -204,7 +204,7 @@ static const struct debugfs_reg32 lvts_regs[] = {
static int lvts_debugfs_init(struct device *dev, struct lvts_domain *lvts_td)
{
- struct debugfs_regset32 *regset;
+ struct debugfs_regset32 *regsets;
struct lvts_ctrl *lvts_ctrl;
struct dentry *dentry;
char name[64];
@@ -214,8 +214,14 @@ static int lvts_debugfs_init(struct device *dev, struct lvts_domain *lvts_td)
if (IS_ERR(lvts_td->dom_dentry))
return 0;
+ regsets = devm_kcalloc(dev, lvts_td->num_lvts_ctrl,
+ sizeof(*regsets), GFP_KERNEL);
+ if (!regsets)
+ return 0;
+
for (i = 0; i < lvts_td->num_lvts_ctrl; i++) {
+ struct debugfs_regset32 *regset = ®sets[i];
lvts_ctrl = &lvts_td->lvts_ctrl[i];
sprintf(name, "controller%d", i);
@@ -223,10 +229,6 @@ static int lvts_debugfs_init(struct device *dev, struct lvts_domain *lvts_td)
if (IS_ERR(dentry))
continue;
- regset = devm_kzalloc(dev, sizeof(*regset), GFP_KERNEL);
- if (!regset)
- continue;
-
regset->base = lvts_ctrl->base;
regset->regs = lvts_regs;
regset->nregs = ARRAY_SIZE(lvts_regs);
--
2.44.0
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