[PATCH] padata: use alignment when calculating the number of worker threads

From: Anthony Yznaga
Date: Wed Feb 22 2023 - 19:33:23 EST


For multithreaded jobs the computed chunk size is rounded up by the
caller-specified alignment. However, the number of worker threads to
use is computed using the minimum chunk size without taking alignment
into account. A sufficiently large alignment value can result in too
many worker threads being allocated for the job.

Signed-off-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>
---
kernel/padata.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index e007b8a4b738..4abc536ecdb1 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -491,7 +491,7 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
return;

/* Ensure at least one thread when size < min_chunk. */
- nworks = max(job->size / job->min_chunk, 1ul);
+ nworks = max(job->size / max(job->min_chunk, job->align), 1ul);
nworks = min(nworks, job->max_threads);

if (nworks == 1) {
--
1.8.3.1