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From: Leo Yan To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Adrian Hunter , James Clark , John Garry , Will Deacon , Mike Leach , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Shimin Guo , Yunseong Kim , Athira Rajeev , Quan Zhou , Andrew Jones , Anup Patel , Dapeng Mi , Thomas Falcon , Blake Jones , Swapnil Sapkal , Kan Liang , Howard Chu , Anubhav Shelat , Aditya Bodkhe , Chun-Tse Shao , Andi Kleen , Dmitry Vyukov , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v2 2/6] perf kvm stat: Remove use of the arch directory Message-ID: <20260201170459.GA584@debian-dev> References: <20260131200224.1296136-1-irogers@google.com> <20260131200224.1296136-3-irogers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260131200224.1296136-3-irogers@google.com> X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260201_090523_517183_DD5F8F5C X-CRM114-Status: GOOD ( 15.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Jan 31, 2026 at 12:02:20PM -0800, Ian Rogers wrote: [...] > @@ -1666,7 +1661,7 @@ kvm_events_record(struct perf_kvm_stat *kvm, int argc, const char **argv) > return ret; > } > > - for (events_tp = kvm_events_tp; *events_tp; events_tp++) > + for (events_tp = kvm_events_tp(); *events_tp; events_tp++) > events_tp_size++; > > rec_argc = ARRAY_SIZE(record_args) + argc + 2 + > @@ -1681,7 +1676,7 @@ kvm_events_record(struct perf_kvm_stat *kvm, int argc, const char **argv) > > for (j = 0; j < events_tp_size; j++) { > rec_argv[i++] = STRDUP_FAIL_EXIT("-e"); > - rec_argv[i++] = STRDUP_FAIL_EXIT(kvm_events_tp[j]); > + rec_argv[i++] = STRDUP_FAIL_EXIT(kvm_events_tp()[j]); > } Nitpick: we can assign reuse events_tp throughout the kvm_events_record(). Something like: events_tp = kvm_events_tp(); for (j = 0; events_tp[j]; j++) events_tp_size++; ... for (j = 0; j < events_tp_size; j++) { rec_argv[i++] = STRDUP_FAIL_EXIT("-e"); rec_argv[i++] = STRDUP_FAIL_EXIT(events_tp[j]); } [...] > +int setup_kvm_events_tp(struct perf_kvm_stat *kvm) > +{ > + switch (EM_HOST) { > + case EM_PPC: > + case EM_PPC64: > + return __setup_kvm_events_tp_powerpc(kvm); > + default: > + return 0; > + } > +} > + > +int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid) > +{ > + switch (EM_HOST) { > + case EM_AARCH64: > + return __cpu_isa_init_arm64(kvm); > + case EM_LOONGARCH: > + return __cpu_isa_init_loongarch(kvm); > + case EM_PPC: > + case EM_PPC64: > + return __cpu_isa_init_powerpc(kvm); > + case EM_RISCV: > + return __cpu_isa_init_riscv(kvm); > + case EM_S390: > + return __cpu_isa_init_s390(kvm, cpuid); > + case EM_X86_64: > + case EM_386: > + return __cpu_isa_init_x86(kvm, cpuid); > + default: > + pr_err("Unsupported kvm-stat host %d\n", EM_HOST); > + return -1; > + } > +} For a general solution, I'd prefer to use "install" + callback methods rather than the opened code. E.g., each arch installs a structure with callbacks: struct kvm_stat_arch kvm_stat_aarch64 { .setup_events_tp = NULL; .cpu_isa_init = __cpu_isa_init_arm64; ... }; Then at the init phase, we can install arch's structure: switch (EM_HOST) { case EM_AARCH64: kvm_stat_arch_init(&kvm_stat_aarch64); break; ... } Afterwards, it is no need to check EM_HOST anymore, it can simply invoke the arch's callback: int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid) { if (!arch_kvm_stat || !arch_kvm_stat->cpu_isa_init) return -1; return arch_kvm_stat->cpu_isa_init(kvm, cpuid); } As a result, we can avoid spreading "switch (EM_HOST)" everywhere. Thanks, Leo