Matthew Wilcox (Oracle) d6077e0d38 bounds: support non-power-of-two CONFIG_NR_CPUS
commit f2d5dcb48f7ba9e3ff249d58fc1fa963d374e66a upstream.

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: 90572890d202 ("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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-13 12:51:31 +02:00
..
2024-03-26 18:22:25 -04:00
2023-01-18 11:41:42 +01:00
2023-12-20 15:41:18 +01:00
2021-02-07 15:35:49 +01:00
2020-01-09 10:19:54 +01:00