From patchwork Fri Oct 14 13:47:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007032 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 52FB8C43217 for ; Fri, 14 Oct 2022 13:53:16 +0000 (UTC) Received: from localhost ([::1]:51014 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ojL7j-0008Dr-2W for qemu-devel@archiver.kernel.org; Fri, 14 Oct 2022 09:53:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47102) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ojL2P-00053A-64 for qemu-devel@nongnu.org; Fri, 14 Oct 2022 09:47:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:52837) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ojL2M-0001lf-5U for qemu-devel@nongnu.org; Fri, 14 Oct 2022 09:47:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665755258; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JmU4qW/qMHX4cizrbM9+JYbp01hAFOZCMtWcHYj6Cu4=; b=AVqmsk02Kj9whjEWyDWFY7jKARXwD0cC9iEc1Pb3F2wcZVnCkP161bv2QuWcOKZqx4Geqq h09rREE8PY11Ks/0pPez/DPr4CvG7upZCuMbsYs5aXUM9BiwwlnYnCpD9LoZRXqbfO7cRD nx7G+AtIVgijzIKHHyD3Ss+RYv8kPcg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-483-N2ad4LN4O-G-IzdfdkOGhA-1; Fri, 14 Oct 2022 09:47:35 -0400 X-MC-Unique: N2ad4LN4O-G-IzdfdkOGhA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 07849857AAA; Fri, 14 Oct 2022 13:47:35 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.239]) by smtp.corp.redhat.com (Postfix) with ESMTP id 06F0E208DDBF; Fri, 14 Oct 2022 13:47:30 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 1/7] util: Cleanup and rename os_mem_prealloc() Date: Fri, 14 Oct 2022 15:47:14 +0200 Message-Id: <20221014134720.168738-2-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Let's * give the function a "qemu_*" style name * make sure the parameters in the implementation match the prototype * rename smp_cpus to max_threads, which makes the semantics of that parameter clearer ... and add a function documentation. Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- backends/hostmem.c | 6 +++--- hw/virtio/virtio-mem.c | 2 +- include/qemu/osdep.h | 17 +++++++++++++++-- softmmu/cpus.c | 2 +- util/oslib-posix.c | 24 ++++++++++++------------ util/oslib-win32.c | 8 ++++---- 6 files changed, 36 insertions(+), 23 deletions(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index 4428e06738..491cb10b97 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,7 +232,7 @@ static void host_memory_backend_set_prealloc(Object *obj, bool value, void *ptr = memory_region_get_ram_ptr(&backend->mr); uint64_t sz = memory_region_size(&backend->mr); - os_mem_prealloc(fd, ptr, sz, backend->prealloc_threads, &local_err); + qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, &local_err); if (local_err) { error_propagate(errp, local_err); return; @@ -383,8 +383,8 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) * specified NUMA policy in place. */ if (backend->prealloc) { - os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz, - backend->prealloc_threads, &local_err); + qemu_prealloc_mem(memory_region_get_fd(&backend->mr), ptr, sz, + backend->prealloc_threads, &local_err); if (local_err) { goto out; } diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 30d03e987a..0e9ef4ff19 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -467,7 +467,7 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, int fd = memory_region_get_fd(&vmem->memdev->mr); Error *local_err = NULL; - os_mem_prealloc(fd, area, size, 1, &local_err); + qemu_prealloc_mem(fd, area, size, 1, &local_err); if (local_err) { static bool warned; diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index b1c161c035..e556e45143 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -568,8 +568,21 @@ unsigned long qemu_getauxval(unsigned long type); void qemu_set_tty_echo(int fd, bool echo); -void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus, - Error **errp); +/** + * qemu_prealloc_mem: + * @fd: the fd mapped into the area, -1 for anonymous memory + * @area: start address of the are to preallocate + * @sz: the size of the area to preallocate + * @max_threads: maximum number of threads to use + * @errp: returns an error if this function fails + * + * Preallocate memory (populate/prefault page tables writable) for the virtual + * memory area starting at @area with the size of @sz. After a successful call, + * each page in the area was faulted in writable at least once, for example, + * after allocating file blocks for mapped files. + */ +void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, + Error **errp); /** * qemu_get_pid_name: diff --git a/softmmu/cpus.c b/softmmu/cpus.c index 61b27ff59d..01c94fd298 100644 --- a/softmmu/cpus.c +++ b/softmmu/cpus.c @@ -354,7 +354,7 @@ static void qemu_init_sigbus(void) /* * ALERT: when modifying this, take care that SIGBUS forwarding in - * os_mem_prealloc() will continue working as expected. + * qemu_prealloc_mem() will continue working as expected. */ memset(&action, 0, sizeof(action)); action.sa_flags = SA_SIGINFO; diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 827a7aadba..905cbc27cc 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -329,7 +329,7 @@ static void sigbus_handler(int signal) return; } #endif /* CONFIG_LINUX */ - warn_report("os_mem_prealloc: unrelated SIGBUS detected and ignored"); + warn_report("qemu_prealloc_mem: unrelated SIGBUS detected and ignored"); } static void *do_touch_pages(void *arg) @@ -399,13 +399,13 @@ static void *do_madv_populate_write_pages(void *arg) } static inline int get_memset_num_threads(size_t hpagesize, size_t numpages, - int smp_cpus) + int max_threads) { long host_procs = sysconf(_SC_NPROCESSORS_ONLN); int ret = 1; if (host_procs > 0) { - ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); + ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), max_threads); } /* Especially with gigantic pages, don't create more threads than pages. */ @@ -418,11 +418,11 @@ static inline int get_memset_num_threads(size_t hpagesize, size_t numpages, } static int touch_all_pages(char *area, size_t hpagesize, size_t numpages, - int smp_cpus, bool use_madv_populate_write) + int max_threads, bool use_madv_populate_write) { static gsize initialized = 0; MemsetContext context = { - .num_threads = get_memset_num_threads(hpagesize, numpages, smp_cpus), + .num_threads = get_memset_num_threads(hpagesize, numpages, max_threads), }; size_t numpages_per_thread, leftover; void *(*touch_fn)(void *); @@ -494,13 +494,13 @@ static bool madv_populate_write_possible(char *area, size_t pagesize) errno != EINVAL; } -void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, - Error **errp) +void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, + Error **errp) { static gsize initialized; int ret; size_t hpagesize = qemu_fd_getpagesize(fd); - size_t numpages = DIV_ROUND_UP(memory, hpagesize); + size_t numpages = DIV_ROUND_UP(sz, hpagesize); bool use_madv_populate_write; struct sigaction act; @@ -530,24 +530,24 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, if (ret) { qemu_mutex_unlock(&sigbus_mutex); error_setg_errno(errp, errno, - "os_mem_prealloc: failed to install signal handler"); + "qemu_prealloc_mem: failed to install signal handler"); return; } } /* touch pages simultaneously */ - ret = touch_all_pages(area, hpagesize, numpages, smp_cpus, + ret = touch_all_pages(area, hpagesize, numpages, max_threads, use_madv_populate_write); if (ret) { error_setg_errno(errp, -ret, - "os_mem_prealloc: preallocating memory failed"); + "qemu_prealloc_mem: preallocating memory failed"); } if (!use_madv_populate_write) { ret = sigaction(SIGBUS, &sigbus_oldact, NULL); if (ret) { /* Terminate QEMU since it can't recover from error */ - perror("os_mem_prealloc: failed to reinstall signal handler"); + perror("qemu_prealloc_mem: failed to reinstall signal handler"); exit(1); } qemu_mutex_unlock(&sigbus_mutex); diff --git a/util/oslib-win32.c b/util/oslib-win32.c index 5723d3eb4c..e1cb725ecc 100644 --- a/util/oslib-win32.c +++ b/util/oslib-win32.c @@ -268,14 +268,14 @@ int getpagesize(void) return system_info.dwPageSize; } -void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, - Error **errp) +void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, + Error **errp) { int i; size_t pagesize = qemu_real_host_page_size(); - memory = (memory + pagesize - 1) & -pagesize; - for (i = 0; i < memory / pagesize; i++) { + sz = (sz + pagesize - 1) & -pagesize; + for (i = 0; i < sz / pagesize; i++) { memset(area + pagesize * i, 0, 1); } } From patchwork Fri Oct 14 13:47:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007034 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EEBFCC433FE for ; Fri, 14 Oct 2022 13:53:18 +0000 (UTC) Received: from localhost ([::1]:51022 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ojL7l-0008IZ-SE for qemu-devel@archiver.kernel.org; Fri, 14 Oct 2022 09:53:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38188) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ojL2R-00057q-1A for qemu-devel@nongnu.org; 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Fri, 14 Oct 2022 09:47:38 -0400 X-MC-Unique: q4Y5tm1QP9CC_Rs3BTW1MQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0CB2286F12D; Fri, 14 Oct 2022 13:47:38 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.239]) by smtp.corp.redhat.com (Postfix) with ESMTP id 43BD4208DDB0; Fri, 14 Oct 2022 13:47:35 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 2/7] util: Introduce qemu_thread_set_affinity() and qemu_thread_get_affinity() Date: Fri, 14 Oct 2022 15:47:15 +0200 Message-Id: <20221014134720.168738-3-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Usually, we let upper layers handle CPU pinning, because pthread_setaffinity_np() (-> sched_setaffinity()) is blocked via seccomp when starting QEMU with -sandbox enable=on,resourcecontrol=deny However, we want to configure and observe the CPU affinity of threads from QEMU directly in some cases when the sandbox option is either not enabled or not active yet. So let's add a way to configure CPU pinning via qemu_thread_set_affinity() and obtain CPU affinity via qemu_thread_get_affinity() and implement them under POSIX using pthread_setaffinity_np() + pthread_getaffinity_np(). Implementation under Windows is possible using SetProcessAffinityMask() + GetProcessAffinityMask(), however, that is left as future work. Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- include/qemu/thread.h | 4 +++ meson.build | 16 +++++++++ util/qemu-thread-posix.c | 70 ++++++++++++++++++++++++++++++++++++++++ util/qemu-thread-win32.c | 12 +++++++ 4 files changed, 102 insertions(+) diff --git a/include/qemu/thread.h b/include/qemu/thread.h index af19f2b3fc..79e507c7f0 100644 --- a/include/qemu/thread.h +++ b/include/qemu/thread.h @@ -185,6 +185,10 @@ void qemu_event_destroy(QemuEvent *ev); void qemu_thread_create(QemuThread *thread, const char *name, void *(*start_routine)(void *), void *arg, int mode); +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits); +int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus, + unsigned long *nbits); void *qemu_thread_join(QemuThread *thread); void qemu_thread_get_self(QemuThread *thread); bool qemu_thread_is_self(QemuThread *thread); diff --git a/meson.build b/meson.build index b686dfef75..3e0aa4925d 100644 --- a/meson.build +++ b/meson.build @@ -2114,7 +2114,23 @@ config_host_data.set('CONFIG_PTHREAD_CONDATTR_SETCLOCK', cc.links(gnu_source_pre pthread_condattr_setclock(&attr, CLOCK_MONOTONIC); return 0; }''', dependencies: threads)) +config_host_data.set('CONFIG_PTHREAD_AFFINITY_NP', cc.links(gnu_source_prefix + ''' + #include + static void *f(void *p) { return NULL; } + int main(void) + { + int setsize = CPU_ALLOC_SIZE(64); + pthread_t thread; + cpu_set_t *cpuset; + pthread_create(&thread, 0, f, 0); + cpuset = CPU_ALLOC(64); + CPU_ZERO_S(setsize, cpuset); + pthread_setaffinity_np(thread, setsize, cpuset); + pthread_getaffinity_np(thread, setsize, cpuset); + CPU_FREE(cpuset); + return 0; + }''', dependencies: threads)) config_host_data.set('CONFIG_SIGNALFD', cc.links(gnu_source_prefix + ''' #include #include diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index ac1d56e673..bae938c670 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -16,6 +16,7 @@ #include "qemu/notify.h" #include "qemu-thread-common.h" #include "qemu/tsan.h" +#include "qemu/bitmap.h" static bool name_threads; @@ -552,6 +553,75 @@ void qemu_thread_create(QemuThread *thread, const char *name, pthread_attr_destroy(&attr); } +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits) +{ +#if defined(CONFIG_PTHREAD_AFFINITY_NP) + const size_t setsize = CPU_ALLOC_SIZE(nbits); + unsigned long value; + cpu_set_t *cpuset; + int err; + + cpuset = CPU_ALLOC(nbits); + g_assert(cpuset); + + CPU_ZERO_S(setsize, cpuset); + value = find_first_bit(host_cpus, nbits); + while (value < nbits) { + CPU_SET_S(value, setsize, cpuset); + value = find_next_bit(host_cpus, nbits, value + 1); + } + + err = pthread_setaffinity_np(thread->thread, setsize, cpuset); + CPU_FREE(cpuset); + return err; +#else + return -ENOSYS; +#endif +} + +int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus, + unsigned long *nbits) +{ +#if defined(CONFIG_PTHREAD_AFFINITY_NP) + unsigned long tmpbits; + cpu_set_t *cpuset; + size_t setsize; + int i, err; + + tmpbits = CPU_SETSIZE; + while (true) { + setsize = CPU_ALLOC_SIZE(tmpbits); + cpuset = CPU_ALLOC(tmpbits); + g_assert(cpuset); + + err = pthread_getaffinity_np(thread->thread, setsize, cpuset); + if (err) { + CPU_FREE(cpuset); + if (err != -EINVAL) { + return err; + } + tmpbits *= 2; + } else { + break; + } + } + + /* Convert the result into a proper bitmap. */ + *nbits = tmpbits; + *host_cpus = bitmap_new(tmpbits); + for (i = 0; i < tmpbits; i++) { + if (CPU_ISSET(i, cpuset)) { + set_bit(i, *host_cpus); + } + } + CPU_FREE(cpuset); + return 0; +#else + return -ENOSYS; +#endif +} + void qemu_thread_get_self(QemuThread *thread) { thread->thread = pthread_self(); diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c index b9a467d7db..69db254ac7 100644 --- a/util/qemu-thread-win32.c +++ b/util/qemu-thread-win32.c @@ -477,6 +477,18 @@ void qemu_thread_create(QemuThread *thread, const char *name, thread->data = data; } +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits) +{ + return -ENOSYS; +} + +int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus, + unsigned long *nbits) +{ + return -ENOSYS; +} + void qemu_thread_get_self(QemuThread *thread) { thread->data = qemu_thread_data; From patchwork Fri Oct 14 13:47:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007036 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 282C8C433FE for ; Fri, 14 Oct 2022 13:56:26 +0000 (UTC) Received: from localhost ([::1]:60336 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ojLAn-0004D2-6c for qemu-devel@archiver.kernel.org; Fri, 14 Oct 2022 09:56:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38192) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ojL2V-0005CV-QX for qemu-devel@nongnu.org; Fri, 14 Oct 2022 09:47:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49572) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ojL2T-0001mu-H2 for qemu-devel@nongnu.org; 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Fri, 14 Oct 2022 13:47:40 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.239]) by smtp.corp.redhat.com (Postfix) with ESMTP id 61DD320227AB; Fri, 14 Oct 2022 13:47:38 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 3/7] util: Introduce ThreadContext user-creatable object Date: Fri, 14 Oct 2022 15:47:16 +0200 Message-Id: <20221014134720.168738-4-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Setting the CPU affinity of QEMU threads is a bit problematic, because QEMU doesn't always have permissions to set the CPU affinity itself, for example, with seccomp after initialized by QEMU: -sandbox enable=on,resourcecontrol=deny General information about CPU affinities can be found in the man page of taskset: CPU affinity is a scheduler property that "bonds" a process to a given set of CPUs on the system. The Linux scheduler will honor the given CPU affinity and the process will not run on any other CPUs. While upper layers are already aware of how to handle CPU affinities for long-lived threads like iothreads or vcpu threads, especially short-lived threads, as used for memory-backend preallocation, are more involved to handle. These threads are created on demand and upper layers are not even able to identify and configure them. Introduce the concept of a ThreadContext, that is essentially a thread used for creating new threads. All threads created via that context thread inherit the configured CPU affinity. Consequently, it's sufficient to create a ThreadContext and configure it once, and have all threads created via that ThreadContext inherit the same CPU affinity. The CPU affinity of a ThreadContext can be configured two ways: (1) Obtaining the thread id via the "thread-id" property and setting the CPU affinity manually (e.g., via taskset). (2) Setting the "cpu-affinity" property and letting QEMU try set the CPU affinity itself. This will fail if QEMU doesn't have permissions to do so anymore after seccomp was initialized. A simple QEMU example to set the CPU affinity to host CPU 0,1,6,7 would be: qemu-system-x86_64 -S \ -object thread-context,id=tc1,cpu-affinity=0-1,cpu-affinity=6-7 And we can query it via HMP/QMP: (qemu) qom-get tc1 cpu-affinity [ 0, 1, 6, 7 ] But note that due to dynamic library loading this example will not work before we actually make use of thread_context_create_thread() in QEMU code, because the type will otherwise not get registered. We'll wire this up next to make it work. In general, the interface behaves like pthread_setaffinity_np(): host CPU numbers that are currently not available are ignored; only host CPU numbers that are impossible with the current kernel will fail. If the list of host CPU numbers does not include a single CPU that is available, setting the CPU affinity will fail. A ThreadContext can be reused, simply by reconfiguring the CPU affinity. Note that the CPU affinity of previously created threads will not get adjusted. Reviewed-by: Michal Privoznik Acked-by: Markus Armbruster Signed-off-by: David Hildenbrand --- include/qemu/thread-context.h | 57 +++++++ qapi/qom.json | 17 +++ util/meson.build | 1 + util/oslib-posix.c | 1 + util/thread-context.c | 278 ++++++++++++++++++++++++++++++++++ 5 files changed, 354 insertions(+) create mode 100644 include/qemu/thread-context.h create mode 100644 util/thread-context.c diff --git a/include/qemu/thread-context.h b/include/qemu/thread-context.h new file mode 100644 index 0000000000..2ebd6b7fe1 --- /dev/null +++ b/include/qemu/thread-context.h @@ -0,0 +1,57 @@ +/* + * QEMU Thread Context + * + * Copyright Red Hat Inc., 2022 + * + * Authors: + * David Hildenbrand + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef SYSEMU_THREAD_CONTEXT_H +#define SYSEMU_THREAD_CONTEXT_H + +#include "qapi/qapi-types-machine.h" +#include "qemu/thread.h" +#include "qom/object.h" + +#define TYPE_THREAD_CONTEXT "thread-context" +OBJECT_DECLARE_TYPE(ThreadContext, ThreadContextClass, + THREAD_CONTEXT) + +struct ThreadContextClass { + ObjectClass parent_class; +}; + +struct ThreadContext { + /* private */ + Object parent; + + /* private */ + unsigned int thread_id; + QemuThread thread; + + /* Semaphore to wait for context thread action. */ + QemuSemaphore sem; + /* Semaphore to wait for action in context thread. */ + QemuSemaphore sem_thread; + /* Mutex to synchronize requests. */ + QemuMutex mutex; + + /* Commands for the thread to execute. */ + int thread_cmd; + void *thread_cmd_data; + + /* CPU affinity bitmap used for initialization. */ + unsigned long *init_cpu_bitmap; + int init_cpu_nbits; +}; + +void thread_context_create_thread(ThreadContext *tc, QemuThread *thread, + const char *name, + void *(*start_routine)(void *), void *arg, + int mode); + +#endif /* SYSEMU_THREAD_CONTEXT_H */ diff --git a/qapi/qom.json b/qapi/qom.json index 80dd419b39..8013ba4b82 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -830,6 +830,21 @@ 'reduced-phys-bits': 'uint32', '*kernel-hashes': 'bool' } } +## +# @ThreadContextProperties: +# +# Properties for thread context objects. +# +# @cpu-affinity: the list of host CPU numbers used as CPU affinity for all +# threads created in the thread context (default: QEMU main +# thread CPU affinity) +# +# Since: 7.2 +## +{ 'struct': 'ThreadContextProperties', + 'data': { '*cpu-affinity': ['uint16'] } } + + ## # @ObjectType: # @@ -882,6 +897,7 @@ { 'name': 'secret_keyring', 'if': 'CONFIG_SECRET_KEYRING' }, 'sev-guest', + 'thread-context', 's390-pv-guest', 'throttle-group', 'tls-creds-anon', @@ -948,6 +964,7 @@ 'secret_keyring': { 'type': 'SecretKeyringProperties', 'if': 'CONFIG_SECRET_KEYRING' }, 'sev-guest': 'SevGuestProperties', + 'thread-context': 'ThreadContextProperties', 'throttle-group': 'ThrottleGroupProperties', 'tls-creds-anon': 'TlsCredsAnonProperties', 'tls-creds-psk': 'TlsCredsPskProperties', diff --git a/util/meson.build b/util/meson.build index 5e282130df..e97cd2d779 100644 --- a/util/meson.build +++ b/util/meson.build @@ -1,4 +1,5 @@ util_ss.add(files('osdep.c', 'cutils.c', 'unicode.c', 'qemu-timer-common.c')) +util_ss.add(files('thread-context.c')) if not config_host_data.get('CONFIG_ATOMIC64') util_ss.add(files('atomic64.c')) endif diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 905cbc27cc..28305cdea3 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -42,6 +42,7 @@ #include "qemu/cutils.h" #include "qemu/compiler.h" #include "qemu/units.h" +#include "qemu/thread-context.h" #ifdef CONFIG_LINUX #include diff --git a/util/thread-context.c b/util/thread-context.c new file mode 100644 index 0000000000..c921905396 --- /dev/null +++ b/util/thread-context.c @@ -0,0 +1,278 @@ +/* + * QEMU Thread Context + * + * Copyright Red Hat Inc., 2022 + * + * Authors: + * David Hildenbrand + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/thread-context.h" +#include "qapi/error.h" +#include "qapi/qapi-builtin-visit.h" +#include "qapi/visitor.h" +#include "qemu/config-file.h" +#include "qapi/qapi-builtin-visit.h" +#include "qom/object_interfaces.h" +#include "qemu/module.h" +#include "qemu/bitmap.h" + +enum { + TC_CMD_NONE = 0, + TC_CMD_STOP, + TC_CMD_NEW, +}; + +typedef struct ThreadContextCmdNew { + QemuThread *thread; + const char *name; + void *(*start_routine)(void *); + void *arg; + int mode; +} ThreadContextCmdNew; + +static void *thread_context_run(void *opaque) +{ + ThreadContext *tc = opaque; + + tc->thread_id = qemu_get_thread_id(); + qemu_sem_post(&tc->sem); + + while (true) { + /* + * Threads inherit the CPU affinity of the creating thread. For this + * reason, we create new (especially short-lived) threads from our + * persistent context thread. + * + * Especially when QEMU is not allowed to set the affinity itself, + * management tools can simply set the affinity of the context thread + * after creating the context, to have new threads created via + * the context inherit the CPU affinity automatically. + */ + switch (tc->thread_cmd) { + case TC_CMD_NONE: + break; + case TC_CMD_STOP: + tc->thread_cmd = TC_CMD_NONE; + qemu_sem_post(&tc->sem); + return NULL; + case TC_CMD_NEW: { + ThreadContextCmdNew *cmd_new = tc->thread_cmd_data; + + qemu_thread_create(cmd_new->thread, cmd_new->name, + cmd_new->start_routine, cmd_new->arg, + cmd_new->mode); + tc->thread_cmd = TC_CMD_NONE; + tc->thread_cmd_data = NULL; + qemu_sem_post(&tc->sem); + break; + } + default: + g_assert_not_reached(); + } + qemu_sem_wait(&tc->sem_thread); + } +} + +static void thread_context_set_cpu_affinity(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + ThreadContext *tc = THREAD_CONTEXT(obj); + uint16List *l, *host_cpus = NULL; + unsigned long *bitmap = NULL; + int nbits = 0, ret; + Error *err = NULL; + + visit_type_uint16List(v, name, &host_cpus, &err); + if (err) { + error_propagate(errp, err); + return; + } + + if (!host_cpus) { + error_setg(errp, "CPU list is empty"); + goto out; + } + + for (l = host_cpus; l; l = l->next) { + nbits = MAX(nbits, l->value + 1); + } + bitmap = bitmap_new(nbits); + for (l = host_cpus; l; l = l->next) { + set_bit(l->value, bitmap); + } + + if (tc->thread_id != -1) { + /* + * Note: we won't be adjusting the affinity of any thread that is still + * around, but only the affinity of the context thread. + */ + ret = qemu_thread_set_affinity(&tc->thread, bitmap, nbits); + if (ret) { + error_setg(errp, "Setting CPU affinity failed: %s", strerror(ret)); + } + } else { + tc->init_cpu_bitmap = bitmap; + bitmap = NULL; + tc->init_cpu_nbits = nbits; + } +out: + g_free(bitmap); + qapi_free_uint16List(host_cpus); +} + +static void thread_context_get_cpu_affinity(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + unsigned long *bitmap, nbits, value; + ThreadContext *tc = THREAD_CONTEXT(obj); + uint16List *host_cpus = NULL; + uint16List **tail = &host_cpus; + int ret; + + if (tc->thread_id == -1) { + error_setg(errp, "Object not initialized yet"); + return; + } + + ret = qemu_thread_get_affinity(&tc->thread, &bitmap, &nbits); + if (ret) { + error_setg(errp, "Getting CPU affinity failed: %s", strerror(ret)); + return; + } + + value = find_first_bit(bitmap, nbits); + while (value < nbits) { + QAPI_LIST_APPEND(tail, value); + + value = find_next_bit(bitmap, nbits, value + 1); + } + g_free(bitmap); + + visit_type_uint16List(v, name, &host_cpus, errp); + qapi_free_uint16List(host_cpus); +} + +static void thread_context_get_thread_id(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + ThreadContext *tc = THREAD_CONTEXT(obj); + uint64_t value = tc->thread_id; + + visit_type_uint64(v, name, &value, errp); +} + +static void thread_context_instance_complete(UserCreatable *uc, Error **errp) +{ + ThreadContext *tc = THREAD_CONTEXT(uc); + char *thread_name; + int ret; + + thread_name = g_strdup_printf("TC %s", + object_get_canonical_path_component(OBJECT(uc))); + qemu_thread_create(&tc->thread, thread_name, thread_context_run, tc, + QEMU_THREAD_JOINABLE); + g_free(thread_name); + + /* Wait until initialization of the thread is done. */ + while (tc->thread_id == -1) { + qemu_sem_wait(&tc->sem); + } + + if (tc->init_cpu_bitmap) { + ret = qemu_thread_set_affinity(&tc->thread, tc->init_cpu_bitmap, + tc->init_cpu_nbits); + if (ret) { + error_setg(errp, "Setting CPU affinity failed: %s", strerror(ret)); + } + g_free(tc->init_cpu_bitmap); + tc->init_cpu_bitmap = NULL; + } +} + +static void thread_context_class_init(ObjectClass *oc, void *data) +{ + UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc); + + ucc->complete = thread_context_instance_complete; + object_class_property_add(oc, "thread-id", "int", + thread_context_get_thread_id, NULL, NULL, + NULL); + object_class_property_add(oc, "cpu-affinity", "int", + thread_context_get_cpu_affinity, + thread_context_set_cpu_affinity, NULL, NULL); +} + +static void thread_context_instance_init(Object *obj) +{ + ThreadContext *tc = THREAD_CONTEXT(obj); + + tc->thread_id = -1; + qemu_sem_init(&tc->sem, 0); + qemu_sem_init(&tc->sem_thread, 0); + qemu_mutex_init(&tc->mutex); +} + +static void thread_context_instance_finalize(Object *obj) +{ + ThreadContext *tc = THREAD_CONTEXT(obj); + + if (tc->thread_id != -1) { + tc->thread_cmd = TC_CMD_STOP; + qemu_sem_post(&tc->sem_thread); + qemu_thread_join(&tc->thread); + } + qemu_sem_destroy(&tc->sem); + qemu_sem_destroy(&tc->sem_thread); + qemu_mutex_destroy(&tc->mutex); +} + +static const TypeInfo thread_context_info = { + .name = TYPE_THREAD_CONTEXT, + .parent = TYPE_OBJECT, + .class_init = thread_context_class_init, + .instance_size = sizeof(ThreadContext), + .instance_init = thread_context_instance_init, + .instance_finalize = thread_context_instance_finalize, + .interfaces = (InterfaceInfo[]) { + { TYPE_USER_CREATABLE }, + { } + } +}; + +static void thread_context_register_types(void) +{ + type_register_static(&thread_context_info); +} +type_init(thread_context_register_types) + +void thread_context_create_thread(ThreadContext *tc, QemuThread *thread, + const char *name, + void *(*start_routine)(void *), void *arg, + int mode) +{ + ThreadContextCmdNew data = { + .thread = thread, + .name = name, + .start_routine = start_routine, + .arg = arg, + .mode = mode, + }; + + qemu_mutex_lock(&tc->mutex); + tc->thread_cmd = TC_CMD_NEW; + tc->thread_cmd_data = &data; + qemu_sem_post(&tc->sem_thread); + + while (tc->thread_cmd != TC_CMD_NONE) { + qemu_sem_wait(&tc->sem); + } + qemu_mutex_unlock(&tc->mutex); +} From patchwork Fri Oct 14 13:47:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007035 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF4B7C4332F for ; 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Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 4/7] util: Add write-only "node-affinity" property for ThreadContext Date: Fri, 14 Oct 2022 15:47:17 +0200 Message-Id: <20221014134720.168738-5-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Let's make it easier to pin threads created via a ThreadContext to all host CPUs currently belonging to a given set of host NUMA nodes -- which is the common case. "node-affinity" is simply a shortcut for setting "cpu-affinity" manually to the list of host CPUs belonging to the set of host nodes. This property can only be written. A simple QEMU example to set the CPU affinity to host node 1 on a system with two nodes, 24 CPUs each, whereby odd-numbered host CPUs belong to host node 1: qemu-system-x86_64 -S \ -object thread-context,id=tc1,node-affinity=1 And we can query the cpu-affinity via HMP/QMP: (qemu) qom-get tc1 cpu-affinity [ 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47 ] We cannot query the node-affinity: (qemu) qom-get tc1 node-affinity Error: Insufficient permission to perform this operation But note that due to dynamic library loading this example will not work before we actually make use of thread_context_create_thread() in QEMU code, because the type will otherwise not get registered. We'll wire this up next to make it work. Note that if the host CPUs for a host node change due do CPU hot(un)plug CPU onlining/offlining (i.e., lscpu output changes) after the ThreadContext was started, the CPU affinity will not get updated. Reviewed-by: Michal Privoznik Acked-by: Markus Armbruster Signed-off-by: David Hildenbrand --- qapi/qom.json | 9 ++++- util/meson.build | 2 +- util/thread-context.c | 84 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 93 insertions(+), 2 deletions(-) diff --git a/qapi/qom.json b/qapi/qom.json index 8013ba4b82..5a2db663f0 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -839,10 +839,17 @@ # threads created in the thread context (default: QEMU main # thread CPU affinity) # +# @node-affinity: the list of host node numbers that will be resolved to a list +# of host CPU numbers used as CPU affinity. This is a shortcut +# for specifying the list of host CPU numbers belonging to the +# host nodes manually by setting @cpu-affinity. (default: QEMU +# main thread affinity) +# # Since: 7.2 ## { 'struct': 'ThreadContextProperties', - 'data': { '*cpu-affinity': ['uint16'] } } + 'data': { '*cpu-affinity': ['uint16'], + '*node-affinity': ['uint16'] } } ## diff --git a/util/meson.build b/util/meson.build index e97cd2d779..c0a7bc54d4 100644 --- a/util/meson.build +++ b/util/meson.build @@ -1,5 +1,5 @@ util_ss.add(files('osdep.c', 'cutils.c', 'unicode.c', 'qemu-timer-common.c')) -util_ss.add(files('thread-context.c')) +util_ss.add(files('thread-context.c'), numa) if not config_host_data.get('CONFIG_ATOMIC64') util_ss.add(files('atomic64.c')) endif diff --git a/util/thread-context.c b/util/thread-context.c index c921905396..4138245332 100644 --- a/util/thread-context.c +++ b/util/thread-context.c @@ -21,6 +21,10 @@ #include "qemu/module.h" #include "qemu/bitmap.h" +#ifdef CONFIG_NUMA +#include +#endif + enum { TC_CMD_NONE = 0, TC_CMD_STOP, @@ -88,6 +92,11 @@ static void thread_context_set_cpu_affinity(Object *obj, Visitor *v, int nbits = 0, ret; Error *err = NULL; + if (tc->init_cpu_bitmap) { + error_setg(errp, "Mixing CPU and node affinity not supported"); + return; + } + visit_type_uint16List(v, name, &host_cpus, &err); if (err) { error_propagate(errp, err); @@ -159,6 +168,79 @@ static void thread_context_get_cpu_affinity(Object *obj, Visitor *v, qapi_free_uint16List(host_cpus); } +static void thread_context_set_node_affinity(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ +#ifdef CONFIG_NUMA + const int nbits = numa_num_possible_cpus(); + ThreadContext *tc = THREAD_CONTEXT(obj); + uint16List *l, *host_nodes = NULL; + unsigned long *bitmap = NULL; + struct bitmask *tmp_cpus; + Error *err = NULL; + int ret, i; + + if (tc->init_cpu_bitmap) { + error_setg(errp, "Mixing CPU and node affinity not supported"); + return; + } + + visit_type_uint16List(v, name, &host_nodes, &err); + if (err) { + error_propagate(errp, err); + return; + } + + if (!host_nodes) { + error_setg(errp, "Node list is empty"); + goto out; + } + + bitmap = bitmap_new(nbits); + tmp_cpus = numa_allocate_cpumask(); + for (l = host_nodes; l; l = l->next) { + numa_bitmask_clearall(tmp_cpus); + ret = numa_node_to_cpus(l->value, tmp_cpus); + if (ret) { + /* We ignore any errors, such as impossible nodes. */ + continue; + } + for (i = 0; i < nbits; i++) { + if (numa_bitmask_isbitset(tmp_cpus, i)) { + set_bit(i, bitmap); + } + } + } + numa_free_cpumask(tmp_cpus); + + if (bitmap_empty(bitmap, nbits)) { + error_setg(errp, "The nodes select no CPUs"); + goto out; + } + + if (tc->thread_id != -1) { + /* + * Note: we won't be adjusting the affinity of any thread that is still + * around for now, but only the affinity of the context thread. + */ + ret = qemu_thread_set_affinity(&tc->thread, bitmap, nbits); + if (ret) { + error_setg(errp, "Setting CPU affinity failed: %s", strerror(ret)); + } + } else { + tc->init_cpu_bitmap = bitmap; + bitmap = NULL; + tc->init_cpu_nbits = nbits; + } +out: + g_free(bitmap); + qapi_free_uint16List(host_nodes); +#else + error_setg(errp, "NUMA node affinity is not supported by this QEMU"); +#endif +} + static void thread_context_get_thread_id(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) @@ -208,6 +290,8 @@ static void thread_context_class_init(ObjectClass *oc, void *data) object_class_property_add(oc, "cpu-affinity", "int", thread_context_get_cpu_affinity, thread_context_set_cpu_affinity, NULL, NULL); + object_class_property_add(oc, "node-affinity", "int", NULL, + thread_context_set_node_affinity, NULL, NULL); } static void thread_context_instance_init(Object *obj) From patchwork Fri Oct 14 13:47:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007037 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 06B99C433FE for ; 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bh=G3jV57M39gjI8r6skaPpM1At09XImBCJLeagtoqEmfs=; b=XsAnGT6WIXsGmDb3ngETfgNVztto/5rcmc3t4/5xHJKrXK/3uZvlJmXZ49g1k00HY4u9Ww cZyviXGT0IlFFVgOJXob0qZZryiH/wTlaWso/0sQISV19fRxitndEu/0uSCdZN5JHwSRYO V5jB0yvuWAqNcWLQ/J1L6YjmEz3xsAo= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-619-HfmZLYIVOSeNr_2eu6a7gQ-1; Fri, 14 Oct 2022 09:48:10 -0400 X-MC-Unique: HfmZLYIVOSeNr_2eu6a7gQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 42BF83C1014F; Fri, 14 Oct 2022 13:47:54 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.239]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1E75020227AB; Fri, 14 Oct 2022 13:47:43 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 5/7] util: Make qemu_prealloc_mem() optionally consume a ThreadContext Date: Fri, 14 Oct 2022 15:47:18 +0200 Message-Id: <20221014134720.168738-6-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" ... and implement it under POSIX. When a ThreadContext is provided, create new threads via the context such that these new threads obtain a properly configured CPU affinity. Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- backends/hostmem.c | 5 +++-- hw/virtio/virtio-mem.c | 2 +- include/qemu/osdep.h | 4 +++- util/oslib-posix.c | 20 ++++++++++++++------ util/oslib-win32.c | 2 +- 5 files changed, 22 insertions(+), 11 deletions(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index 491cb10b97..76f0394490 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,7 +232,8 @@ static void host_memory_backend_set_prealloc(Object *obj, bool value, void *ptr = memory_region_get_ram_ptr(&backend->mr); uint64_t sz = memory_region_size(&backend->mr); - qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, &local_err); + qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, NULL, + &local_err); if (local_err) { error_propagate(errp, local_err); return; @@ -384,7 +385,7 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) */ if (backend->prealloc) { qemu_prealloc_mem(memory_region_get_fd(&backend->mr), ptr, sz, - backend->prealloc_threads, &local_err); + backend->prealloc_threads, NULL, &local_err); if (local_err) { goto out; } diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 0e9ef4ff19..ed170def48 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -467,7 +467,7 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, int fd = memory_region_get_fd(&vmem->memdev->mr); Error *local_err = NULL; - qemu_prealloc_mem(fd, area, size, 1, &local_err); + qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err); if (local_err) { static bool warned; diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index e556e45143..625298c8bc 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -568,6 +568,8 @@ unsigned long qemu_getauxval(unsigned long type); void qemu_set_tty_echo(int fd, bool echo); +typedef struct ThreadContext ThreadContext; + /** * qemu_prealloc_mem: * @fd: the fd mapped into the area, -1 for anonymous memory @@ -582,7 +584,7 @@ void qemu_set_tty_echo(int fd, bool echo); * after allocating file blocks for mapped files. */ void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, - Error **errp); + ThreadContext *tc, Error **errp); /** * qemu_get_pid_name: diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 28305cdea3..59a891b6a8 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -419,7 +419,8 @@ static inline int get_memset_num_threads(size_t hpagesize, size_t numpages, } static int touch_all_pages(char *area, size_t hpagesize, size_t numpages, - int max_threads, bool use_madv_populate_write) + int max_threads, ThreadContext *tc, + bool use_madv_populate_write) { static gsize initialized = 0; MemsetContext context = { @@ -458,9 +459,16 @@ static int touch_all_pages(char *area, size_t hpagesize, size_t numpages, context.threads[i].numpages = numpages_per_thread + (i < leftover); context.threads[i].hpagesize = hpagesize; context.threads[i].context = &context; - qemu_thread_create(&context.threads[i].pgthread, "touch_pages", - touch_fn, &context.threads[i], - QEMU_THREAD_JOINABLE); + if (tc) { + thread_context_create_thread(tc, &context.threads[i].pgthread, + "touch_pages", + touch_fn, &context.threads[i], + QEMU_THREAD_JOINABLE); + } else { + qemu_thread_create(&context.threads[i].pgthread, "touch_pages", + touch_fn, &context.threads[i], + QEMU_THREAD_JOINABLE); + } addr += context.threads[i].numpages * hpagesize; } @@ -496,7 +504,7 @@ static bool madv_populate_write_possible(char *area, size_t pagesize) } void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, - Error **errp) + ThreadContext *tc, Error **errp) { static gsize initialized; int ret; @@ -537,7 +545,7 @@ void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, } /* touch pages simultaneously */ - ret = touch_all_pages(area, hpagesize, numpages, max_threads, + ret = touch_all_pages(area, hpagesize, numpages, max_threads, tc, use_madv_populate_write); if (ret) { error_setg_errno(errp, -ret, diff --git a/util/oslib-win32.c b/util/oslib-win32.c index e1cb725ecc..a67cb3822e 100644 --- a/util/oslib-win32.c +++ b/util/oslib-win32.c @@ -269,7 +269,7 @@ int getpagesize(void) } void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, - Error **errp) + ThreadContext *tc, Error **errp) { int i; size_t pagesize = qemu_real_host_page_size(); From patchwork Fri Oct 14 13:47:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007038 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9B1A2C433FE for ; Fri, 14 Oct 2022 13:59:27 +0000 (UTC) Received: from localhost ([::1]:46940 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ojLDi-0000Hx-Ky for qemu-devel@archiver.kernel.org; Fri, 14 Oct 2022 09:59:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57176) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ojL2z-00061p-3o for qemu-devel@nongnu.org; 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Fri, 14 Oct 2022 09:48:15 -0400 X-MC-Unique: OagrarvEMLSXFDvcaQwNyQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7A8073C10239; Fri, 14 Oct 2022 13:48:05 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.239]) by smtp.corp.redhat.com (Postfix) with ESMTP id B50B62093CE6; Fri, 14 Oct 2022 13:47:51 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 6/7] hostmem: Allow for specifying a ThreadContext for preallocation Date: Fri, 14 Oct 2022 15:47:19 +0200 Message-Id: <20221014134720.168738-7-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Let's allow for specifying a thread context via the "prealloc-context" property. When set, preallcoation threads will be crated via the thread context -- inheriting the same CPU affinity as the thread context. Pinning preallcoation threads to CPUs can heavily increase performance in NUMA setups, because, preallocation from a CPU close to the target NUMA node(s) is faster then preallocation from a CPU further remote, simply because of memory bandwidth for initializing memory with zeroes. This is especially relevant for very large VMs backed by huge/gigantic pages, whereby preallocation is mandatory. Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- backends/hostmem.c | 12 +++++++++--- include/sysemu/hostmem.h | 2 ++ qapi/qom.json | 4 ++++ 3 files changed, 15 insertions(+), 3 deletions(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index 76f0394490..8640294c10 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,8 +232,8 @@ static void host_memory_backend_set_prealloc(Object *obj, bool value, void *ptr = memory_region_get_ram_ptr(&backend->mr); uint64_t sz = memory_region_size(&backend->mr); - qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, NULL, - &local_err); + qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, + backend->prealloc_context, &local_err); if (local_err) { error_propagate(errp, local_err); return; @@ -385,7 +385,8 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) */ if (backend->prealloc) { qemu_prealloc_mem(memory_region_get_fd(&backend->mr), ptr, sz, - backend->prealloc_threads, NULL, &local_err); + backend->prealloc_threads, + backend->prealloc_context, &local_err); if (local_err) { goto out; } @@ -493,6 +494,11 @@ host_memory_backend_class_init(ObjectClass *oc, void *data) NULL, NULL); object_class_property_set_description(oc, "prealloc-threads", "Number of CPU threads to use for prealloc"); + object_class_property_add_link(oc, "prealloc-context", + TYPE_THREAD_CONTEXT, offsetof(HostMemoryBackend, prealloc_context), + object_property_allow_set_link, OBJ_PROP_LINK_STRONG); + object_class_property_set_description(oc, "prealloc-context", + "Context to use for creating CPU threads for preallocation"); object_class_property_add(oc, "size", "int", host_memory_backend_get_size, host_memory_backend_set_size, diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h index 9ff5c16963..39326f1d4f 100644 --- a/include/sysemu/hostmem.h +++ b/include/sysemu/hostmem.h @@ -18,6 +18,7 @@ #include "qom/object.h" #include "exec/memory.h" #include "qemu/bitmap.h" +#include "qemu/thread-context.h" #define TYPE_MEMORY_BACKEND "memory-backend" OBJECT_DECLARE_TYPE(HostMemoryBackend, HostMemoryBackendClass, @@ -66,6 +67,7 @@ struct HostMemoryBackend { bool merge, dump, use_canonical_path; bool prealloc, is_mapped, share, reserve; uint32_t prealloc_threads; + ThreadContext *prealloc_context; DECLARE_BITMAP(host_nodes, MAX_NODES + 1); HostMemPolicy policy; diff --git a/qapi/qom.json b/qapi/qom.json index 5a2db663f0..969acec8d4 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -578,6 +578,9 @@ # # @prealloc-threads: number of CPU threads to use for prealloc (default: 1) # +# @prealloc-context: thread context to use for creation of preallocation threads +# (default: none) (since 7.2) +# # @share: if false, the memory is private to QEMU; if true, it is shared # (default: false) # @@ -608,6 +611,7 @@ '*policy': 'HostMemPolicy', '*prealloc': 'bool', '*prealloc-threads': 'uint32', + '*prealloc-context': 'str', '*share': 'bool', '*reserve': 'bool', 'size': 'size', From patchwork Fri Oct 14 13:47:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13007039 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0832CC433FE for ; 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bh=lpe73JZt7tu/8KEtLPotB4zUZ0Ze/0klMFMNQMlmrZI=; b=cFIPCTLIwniE0fNEvPj8Z2aZUxMk9STY2cQfxeWxUZe9XVk7ZJZShzbjYMOeH8GotBSX/n +98AiAf0Qt/8Mwf73+NQRKx78TwC/K0wEh6+C/YWdrGoDDx0uVsTQaTESH350J/oy9MxZh c8nowAPDqVVP0qSyopIxYsLVr9LQAtI= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-144-zVSpiBvfOBSr40gYqBa8Qw-1; Fri, 14 Oct 2022 09:48:18 -0400 X-MC-Unique: zVSpiBvfOBSr40gYqBa8Qw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 25DD429324A6; Fri, 14 Oct 2022 13:48:13 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.239]) by smtp.corp.redhat.com (Postfix) with ESMTP id 277812093CEB; Fri, 14 Oct 2022 13:48:02 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v3 7/7] vl: Allow ThreadContext objects to be created before the sandbox option Date: Fri, 14 Oct 2022 15:47:20 +0200 Message-Id: <20221014134720.168738-8-david@redhat.com> In-Reply-To: <20221014134720.168738-1-david@redhat.com> References: <20221014134720.168738-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Currently, there is no way to configure a CPU affinity inside QEMU when the sandbox option disables it for QEMU as a whole, for example, via: -sandbox enable=on,resourcecontrol=deny While ThreadContext objects can be created on the QEMU commandline and the CPU affinity can be configured externally via the thread-id, this is insufficient if a ThreadContext with a certain CPU affinity is already required during QEMU startup, before we can intercept QEMU and configure the CPU affinity. Blocking sched_setaffinity() was introduced in 24f8cdc57224 ("seccomp: add resourcecontrol argument to command line"), "to avoid any bigger of the process". However, we only care about once QEMU is running, not when the instance starting QEMU explicitly requests a certain CPU affinity on the QEMU comandline. Right now, for NUMA-aware preallocation of memory backends used for initial machine RAM, one has to: 1) Start QEMU with the memory-backend with "prealloc=off" 2) Pause QEMU before it starts the guest (-S) 3) Create ThreadContext, configure the CPU affinity using the thread-id 4) Configure the ThreadContext as "prealloc-context" of the memory backend 5) Trigger preallocation by setting "prealloc=on" To simplify this handling especially for initial machine RAM, allow creation of ThreadContext objects before parsing sandbox options, such that the CPU affinity requested on the QEMU commandline alongside the sandbox option can be set. As ThreadContext objects essentially only create a persistent context thread and set the CPU affinity, this is easily possible. With this change, we can create a ThreadContext with a CPU affinity on the QEMU commandline and use it for preallocation of memory backends glued to the machine (simplified example): To make "-name debug-threads=on" keep working as expected for the context threads, perform earlier parsing of "-name". qemu-system-x86_64 -m 1G \ -object thread-context,id=tc1,cpu-affinity=3-4 \ -object memory-backend-ram,id=pc.ram,size=1G,prealloc=on,prealloc-threads=2,prealloc-context=tc1 \ -machine memory-backend=pc.ram \ -S -monitor stdio -sandbox enable=on,resourcecontrol=deny And while we can query the current CPU affinity: (qemu) qom-get tc1 cpu-affinity [ 3, 4 ] We can no longer change it from QEMU directly: (qemu) qom-set tc1 cpu-affinity 1-2 Error: Setting CPU affinity failed: Operation not permitted Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- softmmu/vl.c | 36 ++++++++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 4 deletions(-) diff --git a/softmmu/vl.c b/softmmu/vl.c index b464da25bc..b5a23420ac 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -1759,6 +1759,27 @@ static void object_option_parse(const char *optarg) visit_free(v); } +/* + * Very early object creation, before the sandbox options have been activated. + */ +static bool object_create_pre_sandbox(const char *type) +{ + /* + * Objects should in general not get initialized "too early" without + * a reason. If you add one, state the reason in a comment! + */ + + /* + * Reason: -sandbox on,resourcecontrol=deny disallows setting CPU + * affinity of threads. + */ + if (g_str_equal(type, "thread-context")) { + return true; + } + + return false; +} + /* * Initial object creation happens before all other * QEMU data types are created. The majority of objects @@ -1773,6 +1794,11 @@ static bool object_create_early(const char *type) * add one, state the reason in a comment! */ + /* Reason: already created. */ + if (object_create_pre_sandbox(type)) { + return false; + } + /* Reason: property "chardev" */ if (g_str_equal(type, "rng-egd") || g_str_equal(type, "qtest")) { @@ -1895,7 +1921,7 @@ static void qemu_create_early_backends(void) */ static bool object_create_late(const char *type) { - return !object_create_early(type); + return !object_create_early(type) && !object_create_pre_sandbox(type); } static void qemu_create_late_backends(void) @@ -2351,6 +2377,11 @@ static int process_runstate_actions(void *opaque, QemuOpts *opts, Error **errp) static void qemu_process_early_options(void) { + qemu_opts_foreach(qemu_find_opts("name"), + parse_name, NULL, &error_fatal); + + object_option_foreach_add(object_create_pre_sandbox); + #ifdef CONFIG_SECCOMP QemuOptsList *olist = qemu_find_opts_err("sandbox", NULL); if (olist) { @@ -2358,9 +2389,6 @@ static void qemu_process_early_options(void) } #endif - qemu_opts_foreach(qemu_find_opts("name"), - parse_name, NULL, &error_fatal); - if (qemu_opts_foreach(qemu_find_opts("action"), process_runstate_actions, NULL, &error_fatal)) { exit(1);