Re: [Devel] [PATCH RHEL9 COMMIT] fs/fuse kio: do not set RPC affinity from a workequeue worker

[Konstantin Khorenko]

disregard

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 08.07.2025 16:27, Konstantin Khorenko wrote:

The commit is pushed to "branch-rh9-5.14.0-427.55.1.vz9.82.x-ovz" and will 
appear at g...@bitbucket.org:openvz/vzkernel.git
after rh9-5.14.0-427.55.1.vz9.82.4
------>
commit 656d21e8a029763e22b8e95969524e3e8d8ff773
Author: Liu Kui <kui....@virtuozzo.com>
Date:   Tue Jul 8 16:14:16 2025 +0800

     fs/fuse kio: do not set RPC affinity from a workequeue worker

A RPC's affinity shouldn't be set from a workqueue worker in case of

     RPC_AFFINITY_RETENT mode, otherwise the RPC could be stuck to one cpu
     forever. When multiple rpcs are stuck to the same cpu overall performance
     degrades significantly.

Fixes: #VSTOR-109481

     https://virtuozzo.atlassian.net/browse/VSTOR-109481

Signed-off-by: Liu Kui <kui....@virtuozzo.com> Feature: fuse: kRPC - single RPC for kernel and userspace

---
  fs/fuse/kio/pcs/pcs_rpc.c | 4 ++++
  1 file changed, 4 insertions(+)

diff --git a/fs/fuse/kio/pcs/pcs_rpc.c b/fs/fuse/kio/pcs/pcs_rpc.c
index 81da47f761555..7e7cc63257702 100644
--- a/fs/fuse/kio/pcs/pcs_rpc.c
+++ b/fs/fuse/kio/pcs/pcs_rpc.c
@@ -802,6 +802,10 @@ static void pcs_rpc_affinity(struct pcs_rpc *ep, bool 
was_idle)
                                break;
                        fallthrough;
                case RPC_AFFINITY_RETENT:
+                       /* Do not set rpc affinity from a workequeue worker */
+                       if (current->flags & PF_WQ_WORKER)
+                               break;
+
                        /* Naive socket-to-cpu binding approach */
                        if (time_is_before_jiffies(ep->cpu_stamp) && was_idle) {
                                ep->cpu_stamp = jiffies + rpc_cpu_time_slice;

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