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Wed, 15 Apr 2026 19:47:30 +0300 From: Fedorov Nikita To: Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , , Juergen Gross , Ajay Kaher , Alexey Makhalov , , Arnd Bergmann , Peter Zijlstra , Boqun Feng , Waiman Long , Darren Hart , Davidlohr Bueso , , Andrew Morton , David Hildenbrand , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , , Gregory Price , Ying Huang , Alistair Popple , Anatoly Stepanov CC: Nikita Fedorov , , , , , , , , , , , , , Subject: [RFC PATCH v3 7/7] futex: use hq-spinlock for hash buckets Date: Thu, 16 Apr 2026 00:44:59 +0800 Message-ID: <20260415164459.2904963-8-fedorov.nikita@h-partners.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260415164459.2904963-1-fedorov.nikita@h-partners.com> References: <20260415164459.2904963-1-fedorov.nikita@h-partners.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.123.66.205] X-ClientProxiedBy: mscpeml500003.china.huawei.com (7.188.49.51) To mscpeml500003.china.huawei.com (7.188.49.51) X-Rspamd-Queue-Id: 2F0361A0007 X-Rspamd-Server: rspam07 X-Stat-Signature: 16n8s7ubbjj8q956d4uaacc65w3hbduy X-Rspam-User: X-HE-Tag: 1776271653-562969 X-HE-Meta: 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 F4IGlJ5l r9v/42uOvqVubKyBL9/S4DGE47WDbGRwS8dasle5uUd721DdPGbbvGRU/XzCPBjNVptYJCN7uIxVyCIsFPt/O1GDnZA4bHwCUJo4ertSWCKGzMCTXVg3Q22ItDGc5Ft7cMlkLhxyy2WtxeeRolfxmZyMbzCmA7zQArmYCHEUAfsW2XtecikBnVHlIGLCOjBZLfpOJ1D2w1V8X09VIxEMnKApC7WDGgTrCo8IjuBLq82HH0pvfqUTHdhYxA+kVzW/SLSgIO+TjgQghLdLMTIEfgYre/MDF2wHZp/cdRsoLG1yYCj7MQLzb503qlwOPz2g/QD42 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Example of hq-spinlock enabled for futex hash-table bucket locks (used in memcached testing scenario) In the evaluated memcached workloads, this improved throughput by up to 10% on AMD EPYC 9654 and by up to 8% on Kunpeng 920, with corresponding latency reductions. Co-developed-by: Anatoly Stepanov Signed-off-by: Anatoly Stepanov Co-developed-by: Nikita Fedorov Signed-off-by: Nikita Fedorov --- kernel/futex/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/futex/core.c b/kernel/futex/core.c index 31e83a0978..042cdc7f75 100644 --- a/kernel/futex/core.c +++ b/kernel/futex/core.c @@ -1521,7 +1521,7 @@ static void futex_hash_bucket_init(struct futex_hash_bucket *fhb, #endif atomic_set(&fhb->waiters, 0); plist_head_init(&fhb->chain); - spin_lock_init(&fhb->lock); + spin_lock_init_hq(&fhb->lock); } #define FH_CUSTOM 0x01 -- 2.34.1