From nobody Tue Jun 18 11:24:46 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1658405389; cv=none; d=zohomail.com; s=zohoarc; b=MczRpTE3MfxZIfnK/Lp6v5Kknjk5dSIAsTGHdv1YmjHvIPhFGrT9zSb4n3LJs271AYGd59WK3/5u//u2nHeg78k6DFawlZYHybGF5dSKit7p41Sw4y1SJeBDxGAEKLbLjFe+KLk3m/XDdG2scClgPg2F2rzFl8lAsn3D/olxylE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1658405389; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=ooPoKSQ4/PhB9OVPcFTiTnhYHJAUVTgVz4SNGMupjzY=; b=LWfAWsv+D+1fSr/bE1+Ujcmbh8Z+2CXYi9kLAaGcfhs5eM0CcHL3U8IddNOydSPdtzFpGU/0v/n+XcSFScwOig/e8NT+bFJVbo/W9uTw1VYykMN0NBf9OQYwvjZqqbEghU2JY6wncdKh7aY4yMcIpx0FrKnKTRZ2l9xmweLlxiM= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1658405389532605.3514327650147; Thu, 21 Jul 2022 05:09:49 -0700 (PDT) Received: from localhost ([::1]:57540 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oEV00-0004bR-Av for importer@patchew.org; Thu, 21 Jul 2022 08:09:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59212) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oEUy8-0001or-Ax for qemu-devel@nongnu.org; Thu, 21 Jul 2022 08:07:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:45445) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oEUy6-0000wa-BT for qemu-devel@nongnu.org; Thu, 21 Jul 2022 08:07:51 -0400 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-156-LwuXejt6MjO82ucCylOBnQ-1; Thu, 21 Jul 2022 08:07:39 -0400 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 8257985A587; Thu, 21 Jul 2022 12:07:39 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.182]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9D5B12026D64; Thu, 21 Jul 2022 12:07:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658405269; 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=ooPoKSQ4/PhB9OVPcFTiTnhYHJAUVTgVz4SNGMupjzY=; b=CzYf4LWj9WwIOpUHV34ZA+xR9FEUVsFZ3x0q+WiSax8NN5uFYET4cG5yaY4P8CWkSE4We+ BXQtNoeokp06hBeLWtannWtMN0IJChDfRiC/pSlPZswS8ByyrKKdp8eTzb/KRFdc6/4SjX r04+gqE04WU1PdYzG1aRBWVDY8eTfoE= X-MC-Unique: LwuXejt6MjO82ucCylOBnQ-1 From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 1/7] util: Cleanup and rename os_mem_prealloc() Date: Thu, 21 Jul 2022 14:07:26 +0200 Message-Id: <20220721120732.118133-2-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405391327100001 Content-Type: text/plain; charset="utf-8" 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. Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- 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 624bb7ecd3..caff42d3a5 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,7 +232,7 @@ static void host_memory_backend_set_prealloc(Object *ob= j, bool value, void *ptr =3D memory_region_get_ram_ptr(&backend->mr); uint64_t sz =3D memory_region_size(&backend->mr); =20 - os_mem_prealloc(fd, ptr, sz, backend->prealloc_threads, &local_err= ); + qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, &local_e= rr); if (local_err) { error_propagate(errp, local_err); return; @@ -393,8 +393,8 @@ 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 =3D memory_region_get_fd(&vmem->memdev->mr); Error *local_err =3D NULL; =20 - os_mem_prealloc(fd, area, size, 1, &local_err); + qemu_prealloc_mem(fd, area, size, 1, &local_err); if (local_err) { static bool warned; =20 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); =20 void qemu_set_tty_echo(int fd, bool echo); =20 -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 vir= tual + * 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 exampl= e, + * after allocating file blocks for mapped files. + */ +void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, + Error **errp); =20 /** * qemu_get_pid_name: diff --git a/softmmu/cpus.c b/softmmu/cpus.c index 23b30484b2..cf8aa70ca5 100644 --- a/softmmu/cpus.c +++ b/softmmu/cpus.c @@ -354,7 +354,7 @@ static void qemu_init_sigbus(void) =20 /* * 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 =3D SA_SIGINFO; diff --git a/util/oslib-posix.c b/util/oslib-posix.c index bffec18869..75e8cdcf3e 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -314,7 +314,7 @@ 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"= ); } =20 static void *do_touch_pages(void *arg) @@ -384,13 +384,13 @@ static void *do_madv_populate_write_pages(void *arg) } =20 static inline int get_memset_num_threads(size_t hpagesize, size_t numpages, - int smp_cpus) + int max_threads) { long host_procs =3D sysconf(_SC_NPROCESSORS_ONLN); int ret =3D 1; =20 if (host_procs > 0) { - ret =3D MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cp= us); + ret =3D MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), max_th= reads); } =20 /* Especially with gigantic pages, don't create more threads than page= s. */ @@ -403,11 +403,11 @@ static inline int get_memset_num_threads(size_t hpage= size, size_t numpages, } =20 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 =3D 0; MemsetContext context =3D { - .num_threads =3D get_memset_num_threads(hpagesize, numpages, smp_c= pus), + .num_threads =3D get_memset_num_threads(hpagesize, numpages, max_t= hreads), }; size_t numpages_per_thread, leftover; void *(*touch_fn)(void *); @@ -479,13 +479,13 @@ static bool madv_populate_write_possible(char *area, = size_t pagesize) errno !=3D EINVAL; } =20 -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 =3D qemu_fd_getpagesize(fd); - size_t numpages =3D DIV_ROUND_UP(memory, hpagesize); + size_t numpages =3D DIV_ROUND_UP(sz, hpagesize); bool use_madv_populate_write; struct sigaction act; =20 @@ -515,24 +515,24 @@ void os_mem_prealloc(int fd, char *area, size_t memor= y, 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; } } =20 /* touch pages simultaneously */ - ret =3D touch_all_pages(area, hpagesize, numpages, smp_cpus, + ret =3D 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"); } =20 if (!use_madv_populate_write) { ret =3D 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; } =20 -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 =3D qemu_real_host_page_size(); =20 - memory =3D (memory + pagesize - 1) & -pagesize; - for (i =3D 0; i < memory / pagesize; i++) { + sz =3D (sz + pagesize - 1) & -pagesize; + for (i =3D 0; i < sz / pagesize; i++) { memset(area + pagesize * i, 0, 1); } } --=20 2.35.3 From nobody Tue Jun 18 11:24:46 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1658405570; cv=none; d=zohomail.com; s=zohoarc; b=gNOxmEfT+Pjc6folOmi3+drnb1iLTDGFHBlXWpE3wZvPIf7WvUpXXSU7xZYUYZScV+VUoxFYtnZTD8c5P+SMDxuA06e2WgysXAIu++DA8sgxnClgHDdY87MNN56tjdJu2nRs32EUiV3NiRGfriEBMQRIHYQBwXU9FlxiPLgzbds= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1658405570; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; 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Tsirkin" , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 2/7] util: Introduce qemu_thread_set_affinity() and qemu_thread_get_affinity() Date: Thu, 21 Jul 2022 14:07:27 +0200 Message-Id: <20220721120732.118133-3-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405571304100001 Content-Type: text/plain; charset="utf-8" Usually, we let upper layers handle CPU pinning, because pthread_setaffinity_np() (-> sched_setaffinity()) is blocked via seccomp when starting QEMU with -sandbox enable=3Don,resourcecontrol=3Ddeny 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. Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- 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 8a8c415fc1..961b3c99ac 100644 --- a/meson.build +++ b/meson.build @@ -2072,7 +2072,23 @@ config_host_data.set('CONFIG_PTHREAD_CONDATTR_SETCLO= CK', 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_pre= fix + ''' + #include =20 + static void *f(void *p) { return NULL; } + int main(void) + { + int setsize =3D CPU_ALLOC_SIZE(64); + pthread_t thread; + cpu_set_t *cpuset; + pthread_create(&thread, 0, f, 0); + cpuset =3D 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" =20 static bool name_threads; =20 @@ -552,6 +553,75 @@ void qemu_thread_create(QemuThread *thread, const char= *name, pthread_attr_destroy(&attr); } =20 +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits) +{ +#if defined(CONFIG_PTHREAD_AFFINITY_NP) + const size_t setsize =3D CPU_ALLOC_SIZE(nbits); + unsigned long value; + cpu_set_t *cpuset; + int err; + + cpuset =3D CPU_ALLOC(nbits); + g_assert(cpuset); + + CPU_ZERO_S(setsize, cpuset); + value =3D find_first_bit(host_cpus, nbits); + while (value < nbits) { + CPU_SET_S(value, setsize, cpuset); + value =3D find_next_bit(host_cpus, nbits, value + 1); + } + + err =3D 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 =3D CPU_SETSIZE; + while (true) { + setsize =3D CPU_ALLOC_SIZE(tmpbits); + cpuset =3D CPU_ALLOC(tmpbits); + g_assert(cpuset); + + err =3D pthread_getaffinity_np(thread->thread, setsize, cpuset); + if (err) { + CPU_FREE(cpuset); + if (err !=3D -EINVAL) { + return err; + } + tmpbits *=3D 2; + } else { + break; + } + } + + /* Convert the result into a proper bitmap. */ + *nbits =3D tmpbits; + *host_cpus =3D bitmap_new(tmpbits); + for (i =3D 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 =3D pthread_self(); diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c index a2d5a6e825..72338148bd 100644 --- a/util/qemu-thread-win32.c +++ b/util/qemu-thread-win32.c @@ -427,6 +427,18 @@ void qemu_thread_create(QemuThread *thread, const char= *name, thread->data =3D data; } =20 +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 =3D qemu_thread_data; --=20 2.35.3 From nobody Tue Jun 18 11:24:46 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1658405668; cv=none; d=zohomail.com; s=zohoarc; b=Z3yaZqpJPqCgVBSqbImZ2Zc1X/x0dKtBVLhkgEKrYgkI9Gyd/ES56MxmJ8xcowgf2k82+ozAixGnLBJBlVay2wWQFsFNBZuJ6k5hOtJzEO9AUbK9PzjaoBeZbmbsQm0rtgzIs7rRWgN3u2rabjNQmi2p8PKhu9QKADDp1MFGz1Q= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1658405668; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=hBbRe241oIn6dwfW5KLA9nuMpaschDSBDr3Vcja/5Ec=; 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David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 3/7] util: Introduce ThreadContext user-creatable object Date: Thu, 21 Jul 2022 14:07:28 +0200 Message-Id: <20220721120732.118133-4-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405669993100001 Content-Type: text/plain; charset="utf-8" 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=3Don,resourcecontrol=3Ddeny While upper layers are already aware how to handl;e 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. (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 ThreadContext can be reused, simply be reconfiguring the CPU affinity. Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- include/qemu/thread-context.h | 58 +++++++ qapi/qom.json | 16 ++ util/meson.build | 1 + util/oslib-posix.c | 1 + util/thread-context.c | 279 ++++++++++++++++++++++++++++++++++ 5 files changed, 355 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..c799cbe7a1 --- /dev/null +++ b/include/qemu/thread-context.h @@ -0,0 +1,58 @@ +/* + * 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 late= r. + * 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 *ar= g, + int mode); + +#endif /* SYSEMU_THREAD_CONTEXT_H */ diff --git a/qapi/qom.json b/qapi/qom.json index 80dd419b39..4775a333ed 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -830,6 +830,20 @@ 'reduced-phys-bits': 'uint32', '*kernel-hashes': 'bool' } } =20 +## +# @ThreadContextProperties: +# +# Properties for thread context objects. +# +# @cpu-affinity: the CPU affinity for all threads created in the thread +# context (default: QEMU main thread affinity) +# +# Since: 7.2 +## +{ 'struct': 'ThreadContextProperties', + 'data': { '*cpu-affinity': ['uint16'] } } + + ## # @ObjectType: # @@ -882,6 +896,7 @@ { 'name': 'secret_keyring', 'if': 'CONFIG_SECRET_KEYRING' }, 'sev-guest', + 'thread-context', 's390-pv-guest', 'throttle-group', 'tls-creds-anon', @@ -948,6 +963,7 @@ '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 75e8cdcf3e..fa66f73bf8 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" =20 #ifdef CONFIG_LINUX #include diff --git a/util/thread-context.c b/util/thread-context.c new file mode 100644 index 0000000000..dcd607c532 --- /dev/null +++ b/util/thread-context.c @@ -0,0 +1,279 @@ +/* + * 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 late= r. + * 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 =3D 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 =3D opaque; + + tc->thread_id =3D qemu_get_thread_id(); + qemu_sem_post(&tc->sem); + + while (true) { + /* + * Threads inherit the CPU affinity of the creating thread. For th= is + * 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 thr= ead + * 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 =3D TC_CMD_NONE; + qemu_sem_post(&tc->sem); + return NULL; + case TC_CMD_NEW: { + ThreadContextCmdNew *cmd_new =3D 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 =3D TC_CMD_NONE; + tc->thread_cmd_data =3D 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 =3D THREAD_CONTEXT(obj); + uint16List *l, *host_cpus =3D NULL; + unsigned long *bitmap =3D NULL; + int nbits =3D 0, ret; + Error *err =3D 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 =3D host_cpus; l; l =3D l->next) { + nbits =3D MAX(nbits, l->value + 1); + } + bitmap =3D bitmap_new(nbits); + for (l =3D host_cpus; l; l =3D l->next) { + set_bit(l->value, bitmap); + } + + if (tc->thread_id !=3D -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 =3D qemu_thread_set_affinity(&tc->thread, bitmap, nbits); + if (ret) { + error_setg(errp, "Setting CPU affinity failed: %s", strerror(r= et)); + } + } else { + tc->init_cpu_bitmap =3D bitmap; + bitmap =3D NULL; + tc->init_cpu_nbits =3D 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 =3D THREAD_CONTEXT(obj); + uint16List *host_cpus =3D NULL; + uint16List **tail =3D &host_cpus; + int ret; + + if (tc->thread_id =3D=3D -1) { + error_setg(errp, "Object not initialized yet"); + return; + } + + ret =3D qemu_thread_get_affinity(&tc->thread, &bitmap, &nbits); + if (ret) { + error_setg(errp, "Getting CPU affinity failed: %s", strerror(ret)); + return; + } + + value =3D find_first_bit(bitmap, nbits); + while (value < nbits) { + QAPI_LIST_APPEND(tail, value); + + value =3D 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 =3D THREAD_CONTEXT(obj); + uint64_t value =3D tc->thread_id; + + visit_type_uint64(v, name, &value, errp); +} + +static void thread_context_instance_complete(UserCreatable *uc, Error **er= rp) +{ + ThreadContext *tc =3D THREAD_CONTEXT(uc); + char *thread_name; + int ret; + + thread_name =3D 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 =3D=3D -1) { + qemu_sem_wait(&tc->sem); + } + + if (tc->init_cpu_bitmap) { + ret =3D 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(r= et)); + } + g_free(tc->init_cpu_bitmap); + tc->init_cpu_bitmap =3D NULL; + } +} + +static void thread_context_class_init(ObjectClass *oc, void *data) +{ + UserCreatableClass *ucc =3D USER_CREATABLE_CLASS(oc); + + ucc->complete =3D 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 =3D THREAD_CONTEXT(obj); + + tc->thread_id =3D -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 =3D THREAD_CONTEXT(obj); + + if (tc->thread_id !=3D -1) { + tc->thread_cmd =3D 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 =3D { + .name =3D TYPE_THREAD_CONTEXT, + .parent =3D TYPE_OBJECT, + .class_init =3D thread_context_class_init, + .instance_size =3D sizeof(ThreadContext), + .instance_init =3D thread_context_instance_init, + .instance_finalize =3D thread_context_instance_finalize, + .interfaces =3D (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 *ar= g, + int mode) +{ + ThreadContextCmdNew data =3D { + .thread =3D thread, + .name =3D name, + .start_routine =3D start_routine, + .arg =3D arg, + .mode =3D mode, + }; + + qemu_mutex_lock(&tc->mutex); + tc->thread_cmd =3D TC_CMD_NEW; + tc->thread_cmd_data =3D &data; + qemu_sem_post(&tc->sem_thread); + + while (tc->thread_cmd !=3D TC_CMD_NONE) { + qemu_sem_wait(&tc->sem); + } + qemu_mutex_unlock(&tc->mutex); +} --=20 2.35.3 From nobody Tue Jun 18 11:24:46 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1658405404; cv=none; d=zohomail.com; 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Thu, 21 Jul 2022 12:07:49 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.182]) by smtp.corp.redhat.com (Postfix) with ESMTP id 296DE2026609; Thu, 21 Jul 2022 12:07:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658405277; 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=wCw1TAqcCJb5ORU7X6193FGqQ1uL8/tP8E9cw5fwHoI=; b=NYv2lW45gb0R6tiwJKA9E4EMfyeUFq2VVVc8umKU0YNAxbP37EtN8CvZLmpM4+9cyqAW0a YRA7A7ZKQt4hwq9kqLMgLThAb5rL/aGD7VkneadNmeIfnDLK8ZuMjgO+Mc17lR/JTUR63w HONfvaiLNdbn/jQvqOuPZZcZZlujEdc= X-MC-Unique: bryPEPrWPFep2ShXY5BDDA-1 From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 4/7] util: Add write-only "node-affinity" property for ThreadContext Date: Thu, 21 Jul 2022 14:07:29 +0200 Message-Id: <20220721120732.118133-5-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405407094100003 Content-Type: text/plain; charset="utf-8" Let's make it easier to pin threads created via a ThreadContext to all current CPUs belonging to given NUMA nodes. As "node-affinity" is simply a shortcut for setting "cpu-affinity", that property cannot be read and if the CPUs for a node change due do CPU hotplug, the CPU affinity will not get updated. Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- qapi/qom.json | 7 +++- util/meson.build | 2 +- util/thread-context.c | 84 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+), 2 deletions(-) diff --git a/qapi/qom.json b/qapi/qom.json index 4775a333ed..d36bf3355f 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -838,10 +838,15 @@ # @cpu-affinity: the CPU affinity for all threads created in the thread # context (default: QEMU main thread affinity) # +# @node-affinity: shortcut for looking up the current CPUs for the given n= odes +# and setting @cpu-affinity (default: QEMU main thread +# affinity) +# # Since: 7.2 ## { 'struct': 'ThreadContextProperties', - 'data': { '*cpu-affinity': ['uint16'] } } + 'data': { '*cpu-affinity': ['uint16'], + '*node-affinity': ['uint16'] } } =20 =20 ## 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 dcd607c532..880f0441be 100644 --- a/util/thread-context.c +++ b/util/thread-context.c @@ -22,6 +22,10 @@ #include "qemu/module.h" #include "qemu/bitmap.h" =20 +#ifdef CONFIG_NUMA +#include +#endif + enum { TC_CMD_NONE =3D 0, TC_CMD_STOP, @@ -89,6 +93,11 @@ static void thread_context_set_cpu_affinity(Object *obj,= Visitor *v, int nbits =3D 0, ret; Error *err =3D NULL; =20 + 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); @@ -160,6 +169,79 @@ static void thread_context_get_cpu_affinity(Object *ob= j, Visitor *v, qapi_free_uint16List(host_cpus); } =20 +static void thread_context_set_node_affinity(Object *obj, Visitor *v, + const char *name, void *opaqu= e, + Error **errp) +{ +#ifdef CONFIG_NUMA + const int nbits =3D numa_num_possible_cpus(); + ThreadContext *tc =3D THREAD_CONTEXT(obj); + uint16List *l, *host_nodes =3D NULL; + unsigned long *bitmap =3D NULL; + struct bitmask *tmp_cpus; + Error *err =3D 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 =3D bitmap_new(nbits); + tmp_cpus =3D numa_allocate_cpumask(); + for (l =3D host_nodes; l; l =3D l->next) { + numa_bitmask_clearall(tmp_cpus); + ret =3D numa_node_to_cpus(l->value, tmp_cpus); + if (ret) { + /* We ignore any errors, such as impossible nodes. */ + continue; + } + for (i =3D 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 !=3D -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 =3D qemu_thread_set_affinity(&tc->thread, bitmap, nbits); + if (ret) { + error_setg(errp, "Setting CPU affinity failed: %s", strerror(r= et)); + } + } else { + tc->init_cpu_bitmap =3D bitmap; + bitmap =3D NULL; + tc->init_cpu_nbits =3D 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) @@ -209,6 +291,8 @@ 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= ); } =20 static void thread_context_instance_init(Object *obj) --=20 2.35.3 From nobody Tue Jun 18 11:24:46 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; 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Thu, 21 Jul 2022 12:07:51 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.182]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6C4722026D64; Thu, 21 Jul 2022 12:07:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658405279; 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=GO964l5V8yi3bUVNm/6c2vjZuWgRNlysVRVTm37q2xI=; b=dMwOsE5jdb3OWIDE3ICPeW679XgL2Yt6pWeSV8jo3gmbvMq3+d18PvrybRm9USH39cG+rU wAVDFm18SnAxYR1p8ZTaD8SurdcaAc0IaShsMAbilXaT9fw20Dmj1nu689Ls4hf7KKKJcu 4SVTMNUFCx5hvcyxXfa0jbjJTHuGkdw= X-MC-Unique: 1SbZK0CLNRewe6o7QkuTMQ-1 From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 5/7] util: Make qemu_prealloc_mem() optionally consume a ThreadContext Date: Thu, 21 Jul 2022 14:07:30 +0200 Message-Id: <20220721120732.118133-6-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405929533100001 Content-Type: text/plain; charset="utf-8" ... and implement it under POSIX. When a ThreadContext is provided, create new threads via the context such that these new threads obtain a porperly configured CPU affinity. Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- 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 caff42d3a5..46bd4cc494 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,7 +232,8 @@ static void host_memory_backend_set_prealloc(Object *ob= j, bool value, void *ptr =3D memory_region_get_ram_ptr(&backend->mr); uint64_t sz =3D memory_region_size(&backend->mr); =20 - qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, &local_e= rr); + qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads, NULL, + &local_err); if (local_err) { error_propagate(errp, local_err); return; @@ -394,7 +395,7 @@ 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 =3D memory_region_get_fd(&vmem->memdev->mr); Error *local_err =3D NULL; =20 - 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; =20 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); =20 void qemu_set_tty_echo(int fd, bool echo); =20 +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); =20 /** * qemu_get_pid_name: diff --git a/util/oslib-posix.c b/util/oslib-posix.c index fa66f73bf8..ce5fea3126 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -404,7 +404,8 @@ static inline int get_memset_num_threads(size_t hpagesi= ze, size_t numpages, } =20 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 =3D 0; MemsetContext context =3D { @@ -443,9 +444,16 @@ static int touch_all_pages(char *area, size_t hpagesiz= e, size_t numpages, context.threads[i].numpages =3D numpages_per_thread + (i < leftove= r); context.threads[i].hpagesize =3D hpagesize; context.threads[i].context =3D &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 +=3D context.threads[i].numpages * hpagesize; } =20 @@ -481,7 +489,7 @@ static bool madv_populate_write_possible(char *area, si= ze_t pagesize) } =20 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; @@ -522,7 +530,7 @@ void qemu_prealloc_mem(int fd, char *area, size_t sz, i= nt max_threads, } =20 /* touch pages simultaneously */ - ret =3D touch_all_pages(area, hpagesize, numpages, max_threads, + ret =3D 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) } =20 void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads, - Error **errp) + ThreadContext *tc, Error **errp) { int i; 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Tsirkin" , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 6/7] hostmem: Allow for specifying a ThreadContext for preallocation Date: Thu, 21 Jul 2022 14:07:31 +0200 Message-Id: <20220721120732.118133-7-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405599527100001 Content-Type: text/plain; charset="utf-8" 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. Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- 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 46bd4cc494..5e730fd7c0 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -232,8 +232,8 @@ static void host_memory_backend_set_prealloc(Object *ob= j, bool value, void *ptr =3D memory_region_get_ram_ptr(&backend->mr); uint64_t sz =3D memory_region_size(&backend->mr); =20 - 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; @@ -395,7 +395,8 @@ 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; } @@ -503,6 +504,11 @@ 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" =20 #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; =20 diff --git a/qapi/qom.json b/qapi/qom.json index d36bf3355f..9caa1a60e3 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: 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', --=20 2.35.3 From nobody Tue Jun 18 11:24:46 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; 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Thu, 21 Jul 2022 08:07:59 -0400 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 F03853C138A9; Thu, 21 Jul 2022 12:07:58 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.182]) by smtp.corp.redhat.com (Postfix) with ESMTP id 445722026D64; Thu, 21 Jul 2022 12:07:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658405282; 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=d7w36JqEwtEyECpPl6nXdvmSWboGE6jsZbpoi6KrEN0=; b=CzBHqhTQ8qqofCa6dhFaNP1OIFdqxOxg53Gp3ZxTfHVhKRrcG4+cAb6P32CjYl07vow1pF PsJQuQR2Rr0MXaSkAS/VLkefPNs9vX11KhYDZvkWR1A73/m0AiRWgi7LL/HYm5nKNuPFga z7uBRprn5ZNdvW1QVn8UHSbZQy2vxxI= X-MC-Unique: 3_ooOJgiMdOQghXspDUV_g-1 From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH RFC 7/7] vl: Allow ThreadContext objects to be created before the sandbox option Date: Thu, 21 Jul 2022 14:07:32 +0200 Message-Id: <20220721120732.118133-8-david@redhat.com> In-Reply-To: <20220721120732.118133-1-david@redhat.com> References: <20220721120732.118133-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658405702350100001 Content-Type: text/plain; charset="utf-8" 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=3Don,resourcecontrol=3Ddeny 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=3Doff" 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=3Don" 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 persistant 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): qemu-system-x86_64 -m 1G \ -object thread-context,id=3Dtc1,cpu-affinity=3D3-4 \ -object memory-backend-ram,id=3Dpc.ram,size=3D1G,prealloc=3Don,prealloc-th= reads=3D2,prealloc-context=3Dtc1 \ -machine memory-backend=3Dpc.ram \ -S -monitor stdio -sandbox enable=3Don,resourcecontrol=3Ddeny 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 Signed-off-by: David Hildenbrand Reviewed-by: Michal Privoznik --- softmmu/vl.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/softmmu/vl.c b/softmmu/vl.c index aabd82e09a..252732cf5d 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -1761,6 +1761,27 @@ static void object_option_parse(const char *optarg) visit_free(v); } =20 +/* + * Very early object creation, before the sandbox options have been activa= ted. + */ +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=3Ddeny 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 @@ -1775,6 +1796,11 @@ static bool object_create_early(const char *type) * add one, state the reason in a comment! */ =20 + /* 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); } =20 static void qemu_create_late_backends(void) @@ -2365,6 +2391,8 @@ static int process_runstate_actions(void *opaque, Qem= uOpts *opts, Error **errp) =20 static void qemu_process_early_options(void) { + object_option_foreach_add(object_create_pre_sandbox); + #ifdef CONFIG_SECCOMP QemuOptsList *olist =3D qemu_find_opts_err("sandbox", NULL); if (olist) { --=20 2.35.3