From: Matthew Wilcox <willy@infradead.org>
To: Rik van Riel <riel@surriel.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>,
Peter Zijlstra <peterz@infradead.org>,
David Hildenbrand <david@redhat.com>,
kernel test robot <oliver.sang@intel.com>,
oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
David Rientjes <rientjes@google.com>,
Hugh Dickins <hughd@google.com>, Jann Horn <jannh@google.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Mel Gorman <mgorman@suse.de>, Muchun Song <muchun.song@linux.dev>,
Peter Xu <peterx@redhat.com>, Will Deacon <will@kernel.org>,
Zach O'Keefe <zokeefe@google.com>,
Dan Carpenter <dan.carpenter@linaro.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Subject: Re: [linus:master] [x86] 4817f70c25: stress-ng.mmapaddr.ops_per_sec 63.0% regression
Date: Wed, 29 Jan 2025 16:12:23 +0000 [thread overview]
Message-ID: <Z5pTZ0XLFzfM5dic@casper.infradead.org> (raw)
In-Reply-To: <20250129105920.7a4bffa1@fangorn>
On Wed, Jan 29, 2025 at 10:59:20AM -0500, Rik van Riel wrote:
> Below is a tentative fix for the issue. It is kind of a big hammer,
> and maybe the RCU people have a better idea on how to solve this
> problem, but it may be worth giving this a try to see if it helps
> with the regression you identified.
Perhaps better to do:
+++ b/mm/page_alloc.c
@@ -97,8 +97,8 @@ static DEFINE_MUTEX(pcp_batch_high_lock);
* On SMP, spin_trylock is sufficient protection.
* On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP.
*/
-#define pcp_trylock_prepare(flags) do { } while (0)
-#define pcp_trylock_finish(flag) do { } while (0)
+#define pcp_trylock_prepare(flags) rcu_read_lock()
+#define pcp_trylock_finish(flag) rcu_reada_unlock()
#else
/* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */
with appropriate comment changes
next prev parent reply other threads:[~2025-01-29 16:12 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-28 9:57 kernel test robot
2025-01-28 10:05 ` David Hildenbrand
2025-01-28 11:31 ` Peter Zijlstra
2025-01-28 11:39 ` David Hildenbrand
2025-01-28 13:28 ` Peter Zijlstra
2025-01-28 13:42 ` David Hildenbrand
2025-01-28 15:59 ` Qi Zheng
2025-01-28 17:06 ` Qi Zheng
2025-01-28 17:51 ` Qi Zheng
2025-01-28 18:35 ` Rik van Riel
2025-01-29 8:14 ` Qi Zheng
2025-01-29 15:23 ` Rik van Riel
2025-01-29 15:59 ` Rik van Riel
2025-01-29 16:12 ` Matthew Wilcox [this message]
2025-01-29 16:14 ` Rik van Riel
2025-01-29 16:36 ` Paul E. McKenney
2025-01-29 16:53 ` Rik van Riel
2025-01-29 17:33 ` Qi Zheng
2025-01-29 17:53 ` Qi Zheng
2025-01-29 19:19 ` Paul E. McKenney
2025-01-31 21:11 ` Rik van Riel
2025-02-01 3:44 ` Qi Zheng
2025-01-29 16:53 ` Frederic Weisbecker
2025-01-29 16:57 ` Rik van Riel
2025-01-29 17:23 ` Frederic Weisbecker
2025-01-29 17:28 ` Paul E. McKenney
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