mirror of
https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
f2d5dcb48f
ilog2() rounds down, so for example when PowerPC 85xx sets CONFIG_NR_CPUS
to 24, we will only allocate 4 bits to store the number of CPUs instead of
5. Use bits_per() instead, which rounds up. Found by code inspection.
The effect of this would probably be a misaccounting when doing NUMA
balancing, so to a user, it would only be a performance penalty. The
effects may be more wide-spread; it's hard to tell.
Link: https://lkml.kernel.org/r/20231010145549.1244748-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Fixes: 90572890d2 ("mm: numa: Change page last {nid,pid} into {cpu,pid}")
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
36 lines
946 B
C
36 lines
946 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Generate definitions needed by the preprocessor.
|
|
* This code generates raw asm output which is post-processed
|
|
* to extract and format the required data.
|
|
*/
|
|
|
|
#define __GENERATING_BOUNDS_H
|
|
/* Include headers that define the enum constants of interest */
|
|
#include <linux/page-flags.h>
|
|
#include <linux/mmzone.h>
|
|
#include <linux/kbuild.h>
|
|
#include <linux/log2.h>
|
|
#include <linux/spinlock_types.h>
|
|
|
|
int main(void)
|
|
{
|
|
/* The enum constants to put into include/generated/bounds.h */
|
|
DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS);
|
|
DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES);
|
|
#ifdef CONFIG_SMP
|
|
DEFINE(NR_CPUS_BITS, bits_per(CONFIG_NR_CPUS));
|
|
#endif
|
|
DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
|
|
#ifdef CONFIG_LRU_GEN
|
|
DEFINE(LRU_GEN_WIDTH, order_base_2(MAX_NR_GENS + 1));
|
|
DEFINE(__LRU_REFS_WIDTH, MAX_NR_TIERS - 2);
|
|
#else
|
|
DEFINE(LRU_GEN_WIDTH, 0);
|
|
DEFINE(__LRU_REFS_WIDTH, 0);
|
|
#endif
|
|
/* End of constants */
|
|
|
|
return 0;
|
|
}
|