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bh=AqSKwBl1Lj03FgccrlDouwvURsMXTaeos2WOpfs/ILw=; b=Qxh2ZOt9dYSZwmGFna2Zd5pVL7Nku7748eaM5+pG0+jDhCjC+mihjqSTFM5hnQOKL25zrw Djfz7EQ8dcV16GXLTyBB8xbP2UH0nANe/QHHv0xnqqPfSUvd6iXXpF/IrWwx6QLQ8Ej3Dz AL+dZRjNGjREKNrYA8hy4qdlIwLsOFg= X-MC-Unique: DKGpRXJiNSmrbI4Gq-AI4Q-1 From: Juan Quintela To: qemu-devel@nongnu.org Cc: Marcel Apfelbaum , "Dr. David Alan Gilbert" , Leonardo Bras , Peter Xu , Eric Blake , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Yanan Wang , Juan Quintela , Markus Armbruster , Eduardo Habkost Subject: [PATCH v7 11/12] multifd: Zero pages transmission Date: Tue, 2 Aug 2022 08:39:06 +0200 Message-Id: <20220802063907.18882-12-quintela@redhat.com> In-Reply-To: <20220802063907.18882-1-quintela@redhat.com> References: <20220802063907.18882-1-quintela@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 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=170.10.129.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 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_LOW=-0.7, 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: 1659423908222100001 Content-Type: text/plain; charset="utf-8" This implements the zero page dection and handling. Signed-off-by: Juan Quintela --- Add comment for offset (dave) Use local variables for offset/block to have shorter lines --- migration/multifd.h | 5 +++++ migration/multifd.c | 41 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 44 insertions(+), 2 deletions(-) diff --git a/migration/multifd.h b/migration/multifd.h index a1b852200d..5931de6f86 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -52,6 +52,11 @@ typedef struct { uint32_t unused32[1]; /* Reserved for future use */ uint64_t unused64[3]; /* Reserved for future use */ char ramblock[256]; + /* + * This array contains the pointers to: + * - normal pages (initial normal_pages entries) + * - zero pages (following zero_pages entries) + */ uint64_t offset[]; } __attribute__((packed)) MultiFDPacket_t; =20 diff --git a/migration/multifd.c b/migration/multifd.c index 4473d9f834..89811619d8 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -11,6 +11,7 @@ */ =20 #include "qemu/osdep.h" +#include "qemu/cutils.h" #include "qemu/rcu.h" #include "exec/target_page.h" #include "sysemu/sysemu.h" @@ -275,6 +276,12 @@ static void multifd_send_fill_packet(MultiFDSendParams= *p) =20 packet->offset[i] =3D cpu_to_be64(temp); } + for (i =3D 0; i < p->zero_num; i++) { + /* there are architectures where ram_addr_t is 32 bit */ + uint64_t temp =3D p->zero[i]; + + packet->offset[p->normal_num + i] =3D cpu_to_be64(temp); + } } =20 static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) @@ -358,6 +365,18 @@ static int multifd_recv_unfill_packet(MultiFDRecvParam= s *p, Error **errp) p->normal[i] =3D offset; } =20 + for (i =3D 0; i < p->zero_num; i++) { + uint64_t offset =3D be64_to_cpu(packet->offset[p->normal_num + i]); + + if (offset > (block->used_length - p->page_size)) { + error_setg(errp, "multifd: offset too long %" PRIu64 + " (max " RAM_ADDR_FMT ")", + offset, block->used_length); + return -1; + } + p->zero[i] =3D offset; + } + return 0; } =20 @@ -648,6 +667,8 @@ static void *multifd_send_thread(void *opaque) { MultiFDSendParams *p =3D opaque; Error *local_err =3D NULL; + /* qemu older than 7.0 don't understand zero page on multifd channel */ + bool use_zero_page =3D migrate_use_multifd_zero_page(); int ret =3D 0; bool use_zero_copy_send =3D migrate_use_zero_copy_send(); =20 @@ -670,6 +691,7 @@ static void *multifd_send_thread(void *opaque) qemu_mutex_lock(&p->mutex); =20 if (p->pending_job) { + RAMBlock *rb =3D p->pages->block; uint64_t packet_num =3D p->packet_num; p->flags =3D 0; if (p->sync_needed) { @@ -688,8 +710,16 @@ static void *multifd_send_thread(void *opaque) } =20 for (int i =3D 0; i < p->pages->num; i++) { - p->normal[p->normal_num] =3D p->pages->offset[i]; - p->normal_num++; + uint64_t offset =3D p->pages->offset[i]; + if (use_zero_page && + buffer_is_zero(rb->host + offset, p->page_size)) { + p->zero[p->zero_num] =3D offset; + p->zero_num++; + ram_release_page(rb->idstr, offset); + } else { + p->normal[p->normal_num] =3D offset; + p->normal_num++; + } } =20 if (p->normal_num) { @@ -1152,6 +1182,13 @@ static void *multifd_recv_thread(void *opaque) } } =20 + for (int i =3D 0; i < p->zero_num; i++) { + void *page =3D p->host + p->zero[i]; + if (!buffer_is_zero(page, p->page_size)) { + memset(page, 0, p->page_size); + } + } + if (sync_needed) { qemu_sem_post(&multifd_recv_state->sem_sync); qemu_sem_wait(&p->sem_sync); --=20 2.37.1