From patchwork Thu Jan 30 10:08:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej S. Szmigiero" X-Patchwork-Id: 13954431 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 B2074C02190 for ; Thu, 30 Jan 2025 10:11:11 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tdRVV-0004d6-TR; Thu, 30 Jan 2025 05:10:46 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdRVU-0004cO-R2 for qemu-devel@nongnu.org; Thu, 30 Jan 2025 05:10:44 -0500 Received: from vps-ovh.mhejs.net ([145.239.82.108]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdRVS-0007Ki-Q7 for qemu-devel@nongnu.org; Thu, 30 Jan 2025 05:10:44 -0500 Received: from MUA by vps-ovh.mhejs.net with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.98) (envelope-from ) id 1tdRVO-00000006TzI-1zX9; Thu, 30 Jan 2025 11:10:38 +0100 From: "Maciej S. Szmigiero" To: Peter Xu , Fabiano Rosas Cc: Alex Williamson , =?utf-8?q?C=C3=A9dric_Le_G?= =?utf-8?q?oater?= , Eric Blake , Markus Armbruster , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= , Avihai Horon , Joao Martins , qemu-devel@nongnu.org Subject: [PATCH v4 17/33] migration/multifd: Make MultiFDSendData a struct Date: Thu, 30 Jan 2025 11:08:38 +0100 Message-ID: X-Mailer: git-send-email 2.48.1 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=145.239.82.108; envelope-from=mhej@vps-ovh.mhejs.net; helo=vps-ovh.mhejs.net X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.037, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Peter Xu The newly introduced device state buffer can be used for either storing VFIO's read() raw data, but already also possible to store generic device states. After noticing that device states may not easily provide a max buffer size (also the fact that RAM MultiFDPages_t after all also want to have flexibility on managing offset[] array), it may not be a good idea to stick with union on MultiFDSendData.. as it won't play well with such flexibility. Switch MultiFDSendData to a struct. It won't consume a lot more space in reality, after all the real buffers were already dynamically allocated, so it's so far only about the two structs (pages, device_state) that will be duplicated, but they're small. With this, we can remove the pretty hard to understand alloc size logic. Because now we can allocate offset[] together with the SendData, and properly free it when the SendData is freed. Signed-off-by: Peter Xu [MSS: Make sure to clear possible device state payload before freeing MultiFDSendData, remove placeholders for other patches not included] Signed-off-by: Maciej S. Szmigiero --- migration/multifd-device-state.c | 5 ----- migration/multifd-nocomp.c | 13 ++++++------- migration/multifd.c | 25 +++++++------------------ migration/multifd.h | 15 +++++++++------ 4 files changed, 22 insertions(+), 36 deletions(-) diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index 2207bea9bf8a..d1674b432ff2 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -16,11 +16,6 @@ static QemuMutex queue_job_mutex; static MultiFDSendData *device_state_send; -size_t multifd_device_state_payload_size(void) -{ - return sizeof(MultiFDDeviceState_t); -} - void multifd_device_state_send_setup(void) { qemu_mutex_init(&queue_job_mutex); diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index c00804652383..ffe75256c9fb 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -25,15 +25,14 @@ static MultiFDSendData *multifd_ram_send; -size_t multifd_ram_payload_size(void) +void multifd_ram_payload_alloc(MultiFDPages_t *pages) { - uint32_t n = multifd_ram_page_count(); + pages->offset = g_new0(ram_addr_t, multifd_ram_page_count()); +} - /* - * We keep an array of page offsets at the end of MultiFDPages_t, - * add space for it in the allocation. - */ - return sizeof(MultiFDPages_t) + n * sizeof(ram_addr_t); +void multifd_ram_payload_free(MultiFDPages_t *pages) +{ + g_clear_pointer(&pages->offset, g_free); } void multifd_ram_save_setup(void) diff --git a/migration/multifd.c b/migration/multifd.c index 61b061a33d35..0b61b8192231 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -105,26 +105,12 @@ struct { MultiFDSendData *multifd_send_data_alloc(void) { - size_t max_payload_size, size_minus_payload; + MultiFDSendData *new = g_new0(MultiFDSendData, 1); - /* - * MultiFDPages_t has a flexible array at the end, account for it - * when allocating MultiFDSendData. Use max() in case other types - * added to the union in the future are larger than - * (MultiFDPages_t + flex array). - */ - max_payload_size = MAX(multifd_ram_payload_size(), - multifd_device_state_payload_size()); - max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload)); - - /* - * Account for any holes the compiler might insert. We can't pack - * the structure because that misaligns the members and triggers - * Waddress-of-packed-member. - */ - size_minus_payload = sizeof(MultiFDSendData) - sizeof(MultiFDPayload); + multifd_ram_payload_alloc(&new->u.ram); + /* Device state allocates its payload on-demand */ - return g_malloc0(size_minus_payload + max_payload_size); + return new; } void multifd_send_data_clear(MultiFDSendData *data) @@ -151,8 +137,11 @@ void multifd_send_data_free(MultiFDSendData *data) return; } + /* This also free's device state payload */ multifd_send_data_clear(data); + multifd_ram_payload_free(&data->u.ram); + g_free(data); } diff --git a/migration/multifd.h b/migration/multifd.h index ddc617db9acb..f7811cc0d0cb 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -115,9 +115,13 @@ typedef struct { uint32_t num; /* number of normal pages */ uint32_t normal_num; + /* + * Pointer to the ramblock. NOTE: it's caller's responsibility to make + * sure the pointer is always valid! + */ RAMBlock *block; - /* offset of each page */ - ram_addr_t offset[]; + /* offset array of each page, managed by multifd */ + ram_addr_t *offset; } MultiFDPages_t; struct MultiFDRecvData { @@ -140,7 +144,7 @@ typedef enum { MULTIFD_PAYLOAD_DEVICE_STATE, } MultiFDPayloadType; -typedef union MultiFDPayload { +typedef struct MultiFDPayload { MultiFDPages_t ram; MultiFDDeviceState_t device_state; } MultiFDPayload; @@ -392,12 +396,11 @@ void multifd_ram_save_cleanup(void); int multifd_ram_flush_and_sync(QEMUFile *f); bool multifd_ram_sync_per_round(void); bool multifd_ram_sync_per_section(void); -size_t multifd_ram_payload_size(void); +void multifd_ram_payload_alloc(MultiFDPages_t *pages); +void multifd_ram_payload_free(MultiFDPages_t *pages); void multifd_ram_fill_packet(MultiFDSendParams *p); int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp); -size_t multifd_device_state_payload_size(void); - void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state); void multifd_device_state_send_setup(void);