On Wed, Mar 27, 2024 at 08:21:25AM -0400, Sasha Levin wrote: > The patch below does not apply to the 5.4-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. Looks like you just need a little more fuzz on the patch. diff --git a/kernel/bounds.c b/kernel/bounds.c index 9795d75b09b2..a94e3769347e 100644 --- a/kernel/bounds.c +++ b/kernel/bounds.c @@ -19,7 +19,7 @@ int main(void) DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS); DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES); #ifdef CONFIG_SMP - DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS)); + DEFINE(NR_CPUS_BITS, bits_per(CONFIG_NR_CPUS)); #endif DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t)); /* End of constants */ > Thanks, > Sasha > > ------------------ original commit in Linus's tree ------------------ > > >From f2d5dcb48f7ba9e3ff249d58fc1fa963d374e66a Mon Sep 17 00:00:00 2001 > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > Date: Tue, 10 Oct 2023 15:55:49 +0100 > Subject: [PATCH] bounds: support non-power-of-two CONFIG_NR_CPUS > > 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@xxxxxxxxxxxxx > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> > Fixes: 90572890d202 ("mm: numa: Change page last {nid,pid} into {cpu,pid}") > Reviewed-by: Rik van Riel <riel@xxxxxxxxxxx> > Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > kernel/bounds.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/bounds.c b/kernel/bounds.c > index b529182e8b04f..c5a9fcd2d6228 100644 > --- a/kernel/bounds.c > +++ b/kernel/bounds.c > @@ -19,7 +19,7 @@ int main(void) > DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS); > DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES); > #ifdef CONFIG_SMP > - DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS)); > + DEFINE(NR_CPUS_BITS, bits_per(CONFIG_NR_CPUS)); > #endif > DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t)); > #ifdef CONFIG_LRU_GEN > -- > 2.43.0 > > > >
