From: Mel Gorman <mgorman@techsingularity.net>
To: Linux-Stable <stable@vger.kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 26/26] kernel/fork.c: virtually mapped stacks: do not disable interrupts
Date: Thu, 20 Jul 2017 22:21:44 +0100 [thread overview]
Message-ID: <20170720212144.18453-27-mgorman@techsingularity.net> (raw)
In-Reply-To: <20170720212144.18453-1-mgorman@techsingularity.net>
From: Christoph Lameter <cl@linux.com>
commit 112166f88cf83dd11486cf1818672d42b540865b upstream.
The reason to disable interrupts seems to be to avoid switching to a
different processor while handling per cpu data using individual loads and
stores. If we use per cpu RMV primitives we will not have to disable
interrupts.
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705171055130.5898@east.gentwo.org
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
kernel/fork.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index e53770d2bf95..d07d1562f314 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -205,19 +205,17 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
void *stack;
int i;
- local_irq_disable();
for (i = 0; i < NR_CACHED_STACKS; i++) {
- struct vm_struct *s = this_cpu_read(cached_stacks[i]);
+ struct vm_struct *s;
+
+ s = this_cpu_xchg(cached_stacks[i], NULL);
if (!s)
continue;
- this_cpu_write(cached_stacks[i], NULL);
tsk->stack_vm_area = s;
- local_irq_enable();
return s->addr;
}
- local_irq_enable();
stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE,
VMALLOC_START, VMALLOC_END,
@@ -245,19 +243,15 @@ static inline void free_thread_stack(struct task_struct *tsk)
{
#ifdef CONFIG_VMAP_STACK
if (task_stack_vm_area(tsk)) {
- unsigned long flags;
int i;
- local_irq_save(flags);
for (i = 0; i < NR_CACHED_STACKS; i++) {
- if (this_cpu_read(cached_stacks[i]))
+ if (this_cpu_cmpxchg(cached_stacks[i],
+ NULL, tsk->stack_vm_area) != NULL)
continue;
- this_cpu_write(cached_stacks[i], tsk->stack_vm_area);
- local_irq_restore(flags);
return;
}
- local_irq_restore(flags);
vfree_atomic(tsk->stack);
return;
--
2.13.1
next prev parent reply other threads:[~2017-07-20 21:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 21:21 [PATCH 00/26] Performance-related backports for 4.12.2 Mel Gorman
2017-07-20 21:21 ` [PATCH 01/26] sched/topology: Refactor function build_overlap_sched_groups() Mel Gorman
2017-07-20 21:21 ` [PATCH 02/26] sched/topology: Fix building of overlapping sched-groups Mel Gorman
2017-07-20 21:21 ` [PATCH 03/26] sched/topology: Simplify build_overlap_sched_groups() Mel Gorman
2017-07-20 21:21 ` [PATCH 04/26] sched/debug: Print the scheduler topology group mask Mel Gorman
2017-07-20 21:21 ` [PATCH 05/26] sched/topology: Verify the first group matches the child domain Mel Gorman
2017-07-20 21:21 ` [PATCH 06/26] sched/topology: Optimize build_group_mask() Mel Gorman
2017-07-20 21:21 ` [PATCH 07/26] sched/topology: Move comment about asymmetric node setups Mel Gorman
2017-07-20 21:21 ` [PATCH 08/26] sched/topology: Remove FORCE_SD_OVERLAP Mel Gorman
2017-07-20 21:21 ` [PATCH 09/26] sched/topology: Fix overlapping sched_group_mask Mel Gorman
2017-07-20 21:21 ` [PATCH 10/26] sched/topology: Small cleanup Mel Gorman
2017-07-20 21:21 ` [PATCH 11/26] sched/topology: Add sched_group_capacity debugging Mel Gorman
2017-07-20 21:21 ` [PATCH 12/26] sched/topology: Fix overlapping sched_group_capacity Mel Gorman
2017-07-20 21:21 ` [PATCH 13/26] sched/topology: Add a few comments Mel Gorman
2017-07-20 21:21 ` [PATCH 14/26] sched/topology: Rewrite get_group() Mel Gorman
2017-07-20 21:21 ` [PATCH 15/26] sched/topology: Simplify sched_group_mask() usage Mel Gorman
2017-07-20 21:21 ` [PATCH 16/26] sched/topology: Rename sched_group_mask() Mel Gorman
2017-07-20 21:21 ` [PATCH 17/26] sched/topology: Rename sched_group_cpus() Mel Gorman
2017-07-20 21:21 ` [PATCH 18/26] vtime, sched/cputime: Remove vtime_account_user() Mel Gorman
2017-07-20 21:21 ` [PATCH 19/26] sched/cputime: Always set tsk->vtime_snap_whence after accounting vtime Mel Gorman
2017-07-20 21:21 ` [PATCH 20/26] sched/cputime: Rename vtime fields Mel Gorman
2017-07-20 21:21 ` [PATCH 21/26] sched/cputime: Move the vtime task fields to their own struct Mel Gorman
2017-07-20 21:21 ` [PATCH 22/26] sched/cputime: Accumulate vtime on top of nsec clocksource Mel Gorman
2017-07-20 21:21 ` [PATCH 23/26] sched/fair: Fix load_balance() affinity redo path Mel Gorman
2017-07-20 21:21 ` [PATCH 24/26] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch Mel Gorman
2017-07-20 21:21 ` [PATCH 25/26] writeback: rework wb_[dec|inc]_stat family of functions Mel Gorman
2017-07-20 21:21 ` Mel Gorman [this message]
2017-07-24 16:44 ` [PATCH 00/26] Performance-related backports for 4.12.2 Mel Gorman
2017-07-24 23:29 ` Greg KH
2017-07-25 8:14 ` Mel Gorman
2017-07-25 15:21 ` Greg KH
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170720212144.18453-27-mgorman@techsingularity.net \
--to=mgorman@techsingularity.net \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).