diff options
| author |   Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2025-05-12 11:27:35 +0200 |
|---|---|---|
| committer |   Paolo Abeni <pabeni@redhat.com> | 2025-05-15 15:23:31 +0200 |
| commit | 0af5928f358c40c1fe5ede79f66f040e23124044 (patch) | |
| tree | dfbac82d8607fa8df428661203fa13075f0685b4 | |
| parent | rds: Disable only bottom halves in rds_page_remainder_alloc() (diff) | |
| download | wireguard-linux-0af5928f358c40c1fe5ede79f66f040e23124044.tar.xz wireguard-linux-0af5928f358c40c1fe5ede79f66f040e23124044.zip | |
rds: Acquire per-CPU pointer within BH disabled section
rds_page_remainder_alloc() obtains the current CPU with get_cpu() while
disabling preemption. Then the CPU number is used to access the per-CPU
data structure via per_cpu().
This can be optimized by relying on local_bh_disable() to provide a
stable CPU number/ avoid migration and then using this_cpu_ptr() to
retrieve the data structure.
Cc: Allison Henderson <allison.henderson@oracle.com>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250512092736.229935-15-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | net/rds/page.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/rds/page.c b/net/rds/page.c index e0dd4f62ea47..58a8548a915a 100644 --- a/net/rds/page.c +++ b/net/rds/page.c @@ -86,8 +86,8 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes, goto out; } - rem = &per_cpu(rds_page_remainders, get_cpu()); local_bh_disable(); + rem = this_cpu_ptr(&rds_page_remainders); while (1) { /* avoid a tiny region getting stuck by tossing it */ @@ -116,12 +116,11 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes, /* alloc if there is nothing for us to use */ local_bh_enable(); - put_cpu(); page = alloc_page(gfp); - rem = &per_cpu(rds_page_remainders, get_cpu()); local_bh_disable(); + rem = this_cpu_ptr(&rds_page_remainders); if (!page) { ret = -ENOMEM; @@ -140,7 +139,6 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes, } local_bh_enable(); - put_cpu(); out: rdsdebug("bytes %lu ret %d %p %u %u\n", bytes, ret, ret ? NULL : sg_page(scat), ret ? 0 : scat->offset, |