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Author: Gang Li 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@linux.dev
Signed-off-by: Gang Li <ligang.bdlg@bytedance.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Gang Li Subject: padata: dispatch works on 2024-03-06 13:04:17 -08:00 committed by Andrew Morton
parent 2e73ff236e
commit eb52286634
3 changed files with 15 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/padata.h
View File

@ -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;
};
/**

14
kernel/padata.c
View File

@ -485,7 +485,8 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
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(struct padata_mt_job *job)
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);

1
mm/mm_init.c
View File

@ -2231,6 +2231,7 @@ static int __init deferred_init_memmap(void *data)
.align = PAGES_PER_SECTION,
.min_chunk = PAGES_PER_SECTION,
.max_threads = max_threads,
.numa_aware = false,
};
padata_do_multithreaded(&job);