From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uros Bizjak Subject: [PATCH 00/10] locking: Introduce local{,64}_try_cmpxchg Date: Sun, 5 Mar 2023 21:56:18 +0100 Message-ID: <20230305205628.27385-1-ubizjak@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678049808; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=hNEkm4zOMdJBSU8KKqreG62DLRxeXn3Xkh8biCMSrGQ=; b=fYF9dMtkj1YXiWLjWXVi108GaUsP78YWiLOBcqczOwcGB1KS3hFQGdzMmnPB40ydKb CJBU4IAcJ0MjxZbPRv/XnGoAjuT4JRbTP5/rspAGr1pVqCKhRoeHY3MISmOrijMZ/1Zu bzRGM/41AcDVAq0R82jvDwaNabVWUjpb24UlLxEmo/ypXHTY5dkWwNInk9ZHOiAeRtfv /SV5xswkUyIS+kqp65TKME9k1EuFNhsY+K7YcAsF17i/iTmekg08B/ESrHCvrUtCJFsT l473Q2p3EZjGHpQi0fM7RSy1MdpNqnqxaUQ0X1U1Z9yt4tvfwyH//k4NXO64wBvCP+Pa DoGA== List-ID: Content-Type: text/plain; charset="us-ascii" To: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Uros Bizjak , Richard Henderson , Ivan Kokshaysky , Matt Turner , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Peter Zijlstra , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Add generic and target specific support for local{,64}_try_cmpxchg and wire up support for all targets that use local_t infrastructure. The patch enables x86 targets to emit special instruction for local_try_cmpxchg and also local64_try_cmpxchg for x86_64. The last patch changes __perf_output_begin in events/ring_buffer to use new locking primitive and improves code from 4b3: 48 8b 82 e8 00 00 00 mov 0xe8(%rdx),%rax 4ba: 48 8b b8 08 04 00 00 mov 0x408(%rax),%rdi 4c1: 8b 42 1c mov 0x1c(%rdx),%eax 4c4: 48 8b 4a 28 mov 0x28(%rdx),%rcx 4c8: 85 c0 test %eax,%eax ... 4ef: 48 89 c8 mov %rcx,%rax 4f2: 48 0f b1 7a 28 cmpxchg %rdi,0x28(%rdx) 4f7: 48 39 c1 cmp %rax,%rcx 4fa: 75 b7 jne 4b3 <...> to 4b2: 48 8b 4a 28 mov 0x28(%rdx),%rcx 4b6: 48 8b 82 e8 00 00 00 mov 0xe8(%rdx),%rax 4bd: 48 8b b0 08 04 00 00 mov 0x408(%rax),%rsi 4c4: 8b 42 1c mov 0x1c(%rdx),%eax 4c7: 85 c0 test %eax,%eax ... 4d4: 48 89 c8 mov %rcx,%rax 4d7: 48 0f b1 72 28 cmpxchg %rsi,0x28(%rdx) 4dc: 0f 85 d0 00 00 00 jne 5b2 <...> ... 5b2: 48 89 c1 mov %rax,%rcx 5b5: e9 fc fe ff ff jmp 4b6 <...> Please note that in addition to removed compare, the load from 0x28(%rdx) gets moved out of the loop and the code is rearranged according to likely/unlikely tags in the source. Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Huacai Chen Cc: WANG Xuerui Cc: Thomas Bogendoerfer Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: Arnd Bergmann Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Namhyung Kim Cc: Ian Rogers Cc: Will Deacon Cc: Boqun Feng Cc: Jiaxun Yang Cc: Jun Yi Uros Bizjak (10): locking/atomic: Add missing cast to try_cmpxchg() fallbacks locking/atomic: Add generic try_cmpxchg{,64}_local support locking/alpha: Wire up local_try_cmpxchg locking/loongarch: Wire up local_try_cmpxchg locking/mips: Wire up local_try_cmpxchg locking/powerpc: Wire up local_try_cmpxchg locking/x86: Wire up local_try_cmpxchg locking/generic: Wire up local{,64}_try_cmpxchg locking/x86: Enable local{,64}_try_cmpxchg perf/ring_buffer: use local_try_cmpxchg in __perf_output_begin arch/alpha/include/asm/local.h | 2 ++ arch/loongarch/include/asm/local.h | 2 ++ arch/mips/include/asm/local.h | 2 ++ arch/powerpc/include/asm/local.h | 11 ++++++ arch/x86/include/asm/cmpxchg.h | 6 ++++ arch/x86/include/asm/local.h | 2 ++ include/asm-generic/local.h | 1 + include/asm-generic/local64.h | 2 ++ include/linux/atomic/atomic-arch-fallback.h | 40 ++++++++++++++++----- include/linux/atomic/atomic-instrumented.h | 20 ++++++++++- kernel/events/ring_buffer.c | 5 +-- scripts/atomic/gen-atomic-fallback.sh | 6 +++- scripts/atomic/gen-atomic-instrumented.sh | 2 +- 13 files changed, 87 insertions(+), 14 deletions(-) -- 2.39.2