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[ Upstream commitf2d5dcb48f] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
36 lines
946 B
C
36 lines
946 B
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Generate definitions needed by the preprocessor.
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* This code generates raw asm output which is post-processed
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* to extract and format the required data.
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*/
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#define __GENERATING_BOUNDS_H
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/* Include headers that define the enum constants of interest */
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#include <linux/page-flags.h>
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#include <linux/mmzone.h>
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#include <linux/kbuild.h>
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#include <linux/log2.h>
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#include <linux/spinlock_types.h>
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int main(void)
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{
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/* The enum constants to put into include/generated/bounds.h */
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DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS);
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DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES);
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#ifdef CONFIG_SMP
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DEFINE(NR_CPUS_BITS, bits_per(CONFIG_NR_CPUS));
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#endif
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DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
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#ifdef CONFIG_LRU_GEN
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DEFINE(LRU_GEN_WIDTH, order_base_2(MAX_NR_GENS + 1));
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DEFINE(__LRU_REFS_WIDTH, MAX_NR_TIERS - 2);
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#else
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DEFINE(LRU_GEN_WIDTH, 0);
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DEFINE(__LRU_REFS_WIDTH, 0);
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#endif
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/* End of constants */
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return 0;
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}
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