xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

treewide: make "nr_cpu_ids" unsigned

Browse Source 
First, number of CPUs can't be negative number.

Second, different signnnedness leads to suboptimal code in the following
cases:

1)
	kmalloc(nr_cpu_ids * sizeof(X));

"int" has to be sign extended to size_t.

2)
	while (loff_t *pos < nr_cpu_ids)

MOVSXD is 1 byte longed than the same MOV.

Other cases exist as well. Basically compiler is told that nr_cpu_ids
can't be negative which can't be deduced if it is "int".

Code savings on allyesconfig kernel: -3KB

	add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370)
	function                                     old     new   delta
	coretemp_cpu_online                          450     512     +62
	rcu_init_one                                1234    1272     +38
	pci_device_probe                             374     399     +25

				...

	pgdat_reclaimable_pages                      628     556     -72
	select_fallback_rq                           446     369     -77
	task_numa_find_cpu                          1923    1807    -116

Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan
2017-09-08 16:14:18 -07:00
committed by Linus Torvalds
parent ac036f9570
commit 9b130ad5bb
17 changed files with 21 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
arch/powerpc/sysdev/xive/native.c
View File

@@ -511,13 +511,13 @@ static bool xive_parse_provisioning(struct device_node *np)
static void xive_native_setup_pools(void)
{
/* Allocate a pool big enough */
pr_debug("XIVE: Allocating VP block for pool size %d\n", nr_cpu_ids);
pr_debug("XIVE: Allocating VP block for pool size %u\n", nr_cpu_ids);
xive_pool_vps = xive_native_alloc_vp_block(nr_cpu_ids);
if (WARN_ON(xive_pool_vps == XIVE_INVALID_VP))
pr_err("XIVE: Failed to allocate pool VP, KVM might not function\n");
pr_debug("XIVE: Pool VPs allocated at 0x%x for %d max CPUs\n",
pr_debug("XIVE: Pool VPs allocated at 0x%x for %u max CPUs\n",
xive_pool_vps, nr_cpu_ids);
}