The patch titled
Subject: padata: dispatch works on different nodes
has been added to the -mm mm-unstable branch. Its filename is
padata-dispatch-works-on-different-nodes.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/padata-dispatch-works-on-different-nodes.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Gang Li <gang.li@xxxxxxxxx>
Subject: padata: dispatch works on different nodes
Date: Thu, 22 Feb 2024 22:04:17 +0800
When a group of tasks that access different nodes are scheduled on the
same node, they may encounter bandwidth bottlenecks and access latency.
Thus, numa_aware flag is introduced here, allowing tasks to be distributed
across different nodes to fully utilize the advantage of multi-node
systems.
Link: https://lkml.kernel.org/r/20240222140422.393911-5-gang.li@xxxxxxxxx
Signed-off-by: Gang Li <ligang.bdlg@xxxxxxxxxxxxx>
Tested-by: David Rientjes <rientjes@xxxxxxxxxx>
Reviewed-by: Muchun Song <muchun.song@xxxxxxxxx>
Reviewed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/padata.h | 2 ++
kernel/padata.c | 14 ++++++++++++--
mm/mm_init.c | 1 +
3 files changed, 15 insertions(+), 2 deletions(-)
--- a/include/linux/padata.h~padata-dispatch-works-on-different-nodes
+++ a/include/linux/padata.h
@@ -137,6 +137,7 @@ struct padata_shell {
* appropriate for one worker thread to do at once.
* @max_threads: Max threads to use for the job, actual number may be less
* depending on task size and minimum chunk size.
+ * @numa_aware: Distribute jobs to different nodes with CPU in a round robin fashion.
*/
struct padata_mt_job {
void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
@@ -146,6 +147,7 @@ struct padata_mt_job {
unsigned long align;
unsigned long min_chunk;
int max_threads;
+ bool numa_aware;
};
/**
--- a/kernel/padata.c~padata-dispatch-works-on-different-nodes
+++ a/kernel/padata.c
@@ -485,7 +485,8 @@ void __init padata_do_multithreaded(stru
struct padata_work my_work, *pw;
struct padata_mt_job_state ps;
LIST_HEAD(works);
- int nworks;
+ int nworks, nid;
+ static atomic_t last_used_nid __initdata;
if (job->size == 0)
return;
@@ -517,7 +518,16 @@ void __init padata_do_multithreaded(stru
ps.chunk_size = roundup(ps.chunk_size, job->align);
list_for_each_entry(pw, &works, pw_list)
- queue_work(system_unbound_wq, &pw->pw_work);
+ if (job->numa_aware) {
+ int old_node = atomic_read(&last_used_nid);
+
+ do {
+ nid = next_node_in(old_node, node_states[N_CPU]);
+ } while (!atomic_try_cmpxchg(&last_used_nid, &old_node, nid));
+ queue_work_node(nid, system_unbound_wq, &pw->pw_work);
+ } else {
+ queue_work(system_unbound_wq, &pw->pw_work);
+ }
/* Use the current thread, which saves starting a workqueue worker. */
padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
--- a/mm/mm_init.c~padata-dispatch-works-on-different-nodes
+++ a/mm/mm_init.c
@@ -2231,6 +2231,7 @@ static int __init deferred_init_memmap(v
.align = PAGES_PER_SECTION,
.min_chunk = PAGES_PER_SECTION,
.max_threads = max_threads,
+ .numa_aware = false,
};
padata_do_multithreaded(&job);
_
Patches currently in -mm which might be from gang.li@xxxxxxxxx are
hugetlb-code-clean-for-hugetlb_hstate_alloc_pages.patch
hugetlb-split-hugetlb_hstate_alloc_pages.patch
hugetlb-pass-next_nid_to_alloc-directly-to-for_each_node_mask_to_alloc.patch
padata-dispatch-works-on-different-nodes.patch
padata-downgrade-padata_do_multithreaded-to-serial-execution-for-non-smp.patch
hugetlb-have-config_hugetlbfs-select-config_padata.patch
hugetlb-parallelize-2m-hugetlb-allocation-and-initialization.patch
hugetlb-parallelize-1g-hugetlb-initialization.patch
