On 13.06.2024 19:38, Linus Torvalds wrote:
On Thu, 13 Jun 2024 at 10:09, Linus Torvalds torvalds@linux-foundation.org wrote:
Is there some broken scripting that people have started using (or have been using for a while and was recently broken)?
... and then when I actually pull the code, I note that the problem where it checked _one_ bogus value has just been replaced with checking _another_ bogus value.
Christ.
What if people use a node ID that is simply outside the range entirely, instead of one of those special node IDs?
And now for memblock_set_node() you should apparently use NUMA_NO_NODE to not get a warning, but for memblock_set_region_node() apparently the right random constant to use is MAX_NUMNODES.
Does *any* of this make sense? No.
How about instead of having two random constants - and not having any range checking that I see - just have *one* random constant for "I have no range", call that NUMA_NO_NODE,
Just to mention it - my understanding is that this is an ongoing process heading in this very direction. I'm not an mm person at all, so I can't tell why the conversion wasn't done / can't be done all in one go.
Jan
and then have a simple helper for "do I have a valid range", and make that be
static inline bool numa_valid_node(int nid) { return (unsigned int)nid < MAX_NUMNODES; }
or something like that? Notice that now *all* of
NUMA_NO_NODE (explicitly no node)
MAX_NUMNODES (randomly used no node)
out of range node (who knows wth firmware tables do?)
will get the same result from that "numa_valid_node()" function.
And at that point you don't need to care, you don't need to warn, and you don't need to have these insane rules where "sometimes you *HAVE* to use NUMA_NO_NODE, or we warn, in other cases MAX_NUMNODES is the thing".
Please? IOW, instead of adding a warning for fragile code, then change some caller to follow the new rules, JUST FIX THE STUPID FRAGILITY!
Or hey, just do
#define NUMA_NO_NODE MAX_NUMNODESand have two names for the *same* constant, instead fo having two different constants with strange semantic differences that seem to make no sense and where the memblock code itself seems to go back-and-forth on it in different contexts.
Linus