x86: Fix slight bug in `shared_per_thread` cache size calculation.

After:
```
    commit af992e7abdc9049714da76cae1e5e18bc4838fb8
    Author: Noah Goldstein <goldstein.w.n@gmail.com>
    Date:   Wed Jun 7 13:18:01 2023 -0500

        x86: Increase `non_temporal_threshold` to roughly `sizeof_L3 / 4`
```

Split `shared` (cumulative cache size) from `shared_per_thread` (cache
size per socket), the `shared_per_thread` *can* be slightly off from
the previous calculation.

Previously we added `core` even if `threads_l2` was invalid, and only
used `threads_l2` to divide `core` if it was present. The changed
version only included `core` if `threads_l2` was valid.

This change restores the old behavior if `threads_l2` is invalid by
adding the entire value of `core`.
Reviewed-by: DJ Delorie <dj@redhat.com>

(cherry picked from commit 47f747217811db35854ea06741be3685e8bbd44d)

1 files changed, 2 insertions, 2 deletions

diff --git a/sysdeps/x86/cacheinfo.c b/sysdeps/x86/cacheinfo.c
index ac98741ac6..62986a7327 100644
--- a/sysdeps/x86/cacheinfo.c
+++ b/sysdeps/x86/cacheinfo.c
@@ -696,8 +696,8 @@ init_cacheinfo (void)
       /* Account for non-inclusive L2 and L3 caches.  */
       if (!inclusive_cache)
 	{
-      if (threads_l2 > 0)
-	shared_per_thread += core / threads_l2;
+      long int core_per_thread = threads_l2 > 0 ? (core / threads_l2) : core;
+      shared_per_thread += core_per_thread;
 	  shared += core;
 	}
     }