From: Dan Carpenter <dan.carpenter@oracle.com>
To: javi.merino@arm.com
Cc: linux-pm@vger.kernel.org
Subject: re: thermal: introduce the Power Allocator governor
Date: Sat, 21 Nov 2015 13:42:54 +0300 [thread overview]
Message-ID: <20151121104254.GA10268@mwanda> (raw)
Hello Javi Merino,
The patch 6b775e870c56: "thermal: introduce the Power Allocator
governor" from Mar 2, 2015, leads to the following static checker
warning:
drivers/thermal/power_allocator.c:304 divvy_up_power()
warn: should 'req_power[i] * power_range' be a 64 bit type?
drivers/thermal/power_allocator.c
288 static void divvy_up_power(u32 *req_power, u32 *max_power, int num_actors,
289 u32 total_req_power, u32 power_range,
290 u32 *granted_power, u32 *extra_actor_power)
291 {
292 u32 extra_power, capped_extra_power;
293 int i;
294
295 /*
296 * Prevent division by 0 if none of the actors request power.
297 */
298 if (!total_req_power)
299 total_req_power = 1;
300
301 capped_extra_power = 0;
302 extra_power = 0;
303 for (i = 0; i < num_actors; i++) {
304 u64 req_range = req_power[i] * power_range;
Both req_power[i] and power_range are u32 so the high bits of req_range
are not used.
305
306 granted_power[i] = DIV_ROUND_CLOSEST_ULL(req_range,
307 total_req_power);
308
309 if (granted_power[i] > max_power[i]) {
310 extra_power += granted_power[i] - max_power[i];
311 granted_power[i] = max_power[i];
312 }
313
314 extra_actor_power[i] = max_power[i] - granted_power[i];
315 capped_extra_power += extra_actor_power[i];
316 }
regards,
dan carpenter
next reply other threads:[~2015-11-21 10:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-21 10:42 Dan Carpenter [this message]
2015-11-23 11:23 ` [PATCH] thermal: power_allocator: req_range multiplication should be a 64 bit type Javi Merino
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