From: Mel Gorman mgorman@techsingularity.net Subject: mm/page_alloc: correct return value of populated elements if bulk array is populated
Dave Jones reported the following
This made it into 5.13 final, and completely breaks NFSD for me (Serving tcp v3 mounts). Existing mounts on clients hang, as do new mounts from new clients. Rebooting the server back to rc7 everything recovers.
The commit b3b64ebd3822 ("mm/page_alloc: do bulk array bounds check after checking populated elements") returns the wrong value if the array is already populated which is interpreted as an allocation failure. Dave reported this fixes his problem and it also passed a test running dbench over NFS.
Link: https://lkml.kernel.org/r/20210628150219.GC3840@techsingularity.net Fixes: b3b64ebd3822 ("mm/page_alloc: do bulk array bounds check after checking populated elements") Signed-off-by: Mel Gorman mgorman@techsingularity.net Reported-by: Dave Jones davej@codemonkey.org.uk Tested-by: Dave Jones davej@codemonkey.org.uk Cc: Dan Carpenter dan.carpenter@oracle.com Cc: Jesper Dangaard Brouer brouer@redhat.com Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org [5.13+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/page_alloc.c~mm-page_alloc-correct-return-value-of-populated-elements-if-bulk-array-is-populated +++ a/mm/page_alloc.c @@ -5058,7 +5058,7 @@ unsigned long __alloc_pages_bulk(gfp_t g
/* Already populated array? */ if (unlikely(page_array && nr_pages - nr_populated == 0)) - return 0; + return nr_populated;
/* Use the single page allocator for one page. */ if (nr_pages - nr_populated == 1) _