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GET /api/patches/2215592/?format=api
{ "id": 2215592, "url": "http://patchwork.ozlabs.org/api/patches/2215592/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260324194333.30004-7-farosas@suse.de/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260324194333.30004-7-farosas@suse.de>", "list_archive_url": null, "date": "2026-03-24T19:43:21", "name": "[RFC,v1,06/17] vmstate: Put array of pointers code together", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "a61744b77c31ff34af84a1ee9f5e72977b209cc6", "submitter": { "id": 85343, "url": "http://patchwork.ozlabs.org/api/people/85343/?format=api", "name": "Fabiano Rosas", "email": "farosas@suse.de" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260324194333.30004-7-farosas@suse.de/mbox/", "series": [ { "id": 497339, "url": "http://patchwork.ozlabs.org/api/series/497339/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=497339", "date": "2026-03-24T19:43:16", "name": "migration: vmstate_save|load changes for peterx", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/497339/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2215592/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2215592/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256\n header.s=susede2_rsa header.b=eiu1YH5y;\n\tdkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=d8S+KYgz;\n\tdkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de\n header.a=rsa-sha256 header.s=susede2_rsa header.b=eiu1YH5y;\n\tdkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=d8S+KYgz;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Tue, 24 Mar 2026 19:43:44 +0000" ], "DKIM-Signature": [ "v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de;\n s=susede2_rsa;\n t=1774381426;\n h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:\n mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=T7Y0B9fYyfVHM63msfI41W8dKbr2u81xFRLOCF+eFX8=;\n b=eiu1YH5y2ROoxm9/sK43I0kvlvGuRJl60enCqX+4yotiNqDJZcNDHqBoJWeLrtYZIYgvMs\n Xws7T7j0roy7YkyGxTyg3XnS+2aG74cPEarzQVy6WYz46yYj4cnmZxH14JzfJqmnXm+YIt\n 3H3bZziqsYNDVvOdHfYlwtBGZUhHFz4=", "v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de;\n s=susede2_ed25519; t=1774381426;\n h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:\n mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=T7Y0B9fYyfVHM63msfI41W8dKbr2u81xFRLOCF+eFX8=;\n b=d8S+KYgzZF0zAx1Ud3Z6ZSze8Sl8A8nb2bTvmo6JO/3OvV/1GFPzxC4etX1US/Gao8Sc8q\n lxcIEpGQ4VcW38AA==", "v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de;\n s=susede2_rsa;\n t=1774381426;\n h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:\n mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=T7Y0B9fYyfVHM63msfI41W8dKbr2u81xFRLOCF+eFX8=;\n b=eiu1YH5y2ROoxm9/sK43I0kvlvGuRJl60enCqX+4yotiNqDJZcNDHqBoJWeLrtYZIYgvMs\n Xws7T7j0roy7YkyGxTyg3XnS+2aG74cPEarzQVy6WYz46yYj4cnmZxH14JzfJqmnXm+YIt\n 3H3bZziqsYNDVvOdHfYlwtBGZUhHFz4=", "v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de;\n s=susede2_ed25519; t=1774381426;\n h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:\n mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=T7Y0B9fYyfVHM63msfI41W8dKbr2u81xFRLOCF+eFX8=;\n b=d8S+KYgzZF0zAx1Ud3Z6ZSze8Sl8A8nb2bTvmo6JO/3OvV/1GFPzxC4etX1US/Gao8Sc8q\n lxcIEpGQ4VcW38AA==" ], "From": "Fabiano Rosas <farosas@suse.de>", "To": "qemu-devel@nongnu.org", "Cc": "Peter Xu <peterx@redhat.com>,\n Alexander Mikhalitsyn <alexander@mihalicyn.com>,\n Juraj Marcin <jmarcin@redhat.com>", "Subject": "[RFC PATCH v1 06/17] vmstate: Put array of pointers code together", "Date": "Tue, 24 Mar 2026 16:43:21 -0300", "Message-ID": "<20260324194333.30004-7-farosas@suse.de>", "X-Mailer": "git-send-email 2.51.0", "In-Reply-To": "<20260324194333.30004-1-farosas@suse.de>", "References": "<20260324194333.30004-1-farosas@suse.de>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Spamd-Result": "default: False [-3.01 / 50.00]; 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envelope-from=farosas@suse.de;\n helo=smtp-out2.suse.de", "X-Spam_score_int": "-43", "X-Spam_score": "-4.4", "X-Spam_bar": "----", "X-Spam_report": "(-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001,\n 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": "qemu development <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "In vmstate_save|load_vmsd[_v], move the code handling\nVMS_ARRAY_OF_POINTER all to the same block. These functions deal with\nsingle elements, scalar arrays and arrays of pointers, of which the\nlatter is the most complex code. Group that use-case so it's easier to\nreason about.\n\nThis allows for a significant design cleanup, which is to stop using\nthe inner_field variable in the case where there is NO pointer\nmarker. Now the inner_field is internal to the VMS_ARRAY_OF_POINTER\ncode.\n\nBy adding a save_field boolean, we can reuse the \"actual field\" write\nfor the !use_marker case. This brings the benefit of being able to\ndrop the field->size specialization. Like so:\n\n===\nbefore:\nsize = vmstate_size();\n\nif (use_marker) {\n inner_field = fake;\n} else {\n inner_field = field;\n}\n\nvmstate_save_field_with_vmdesc(inner_field, size)\n\nif (use_marker && !curr) {\n vmstate_save_field_with_vmdesc(field, field->size)\n}\n\nafter:\nsize = vmstate_size();\n\nif (use_marker) {\n inner_field = fake;\n vmstate_save_field_with_vmdesc(inner_field, 1)\n save_field = !curr;\n}\n\nif (save_field) {\n vmstate_save_field_with_vmdesc(field, size)\n}\n\nSigned-off-by: Fabiano Rosas <farosas@suse.de>\n---\n migration/vmstate.c | 193 +++++++++++++++++++++-----------------------\n 1 file changed, 92 insertions(+), 101 deletions(-)", "diff": "diff --git a/migration/vmstate.c b/migration/vmstate.c\nindex 7a12245d36..a190c3f63f 100644\n--- a/migration/vmstate.c\n+++ b/migration/vmstate.c\n@@ -277,12 +277,6 @@ bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,\n void *first_elem = opaque + field->offset;\n int i, n_elems = vmstate_n_elems(opaque, field);\n int size = vmstate_size(opaque, field);\n- /*\n- * When this is enabled, it means we will always push a ptr\n- * marker first for each element saying if it's populated.\n- */\n- bool use_dynamic_array =\n- field->flags & VMS_ARRAY_OF_POINTER_AUTO_ALLOC;\n \n vmstate_handle_alloc(first_elem, field, opaque);\n if (field->flags & VMS_POINTER) {\n@@ -294,36 +288,40 @@ bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,\n /* If we will process the load of field? */\n bool load_field = true;\n bool ok = true;\n- bool use_marker_field;\n void *curr_elem_p = first_elem + size * i;\n void *curr_elem = curr_elem_p;\n \n if (field->flags & VMS_ARRAY_OF_POINTER) {\n+ bool use_dynamic_array =\n+ field->flags & VMS_ARRAY_OF_POINTER_AUTO_ALLOC;\n+ bool use_marker_field;\n+\n curr_elem = *(void **)curr_elem_p;\n- }\n \n- use_marker_field = use_dynamic_array || (!curr_elem && size);\n+ use_marker_field = use_dynamic_array || !curr_elem;\n \n- if (use_marker_field) {\n- /* Read the marker instead of VMSD first */\n- if (!vmstate_ptr_marker_load(f, &load_field, errp)) {\n- trace_vmstate_load_field_error(field->name, -EINVAL);\n- return false;\n- }\n+ if (use_marker_field) {\n+ /* Read the marker instead of VMSD first */\n+ if (!vmstate_ptr_marker_load(f, &load_field, errp)) {\n+ trace_vmstate_load_field_error(field->name,\n+ -EINVAL);\n+ return false;\n+ }\n \n- if (load_field) {\n- /*\n- * When reaching here, it means we received a\n- * non-NULL ptr marker, so we need to populate the\n- * field before loading it.\n- *\n- * NOTE: do not use vmstate_size() here, because we\n- * need the object size, not entry size of the\n- * array.\n- */\n- curr_elem = g_malloc0(field->size);\n- /* Remember to update the root pointer! */\n- *(void **)curr_elem_p = curr_elem;\n+ if (load_field) {\n+ /*\n+ * When reaching here, it means we received a\n+ * non-NULL ptr marker, so we need to populate the\n+ * field before loading it.\n+ *\n+ * NOTE: do not use vmstate_size() here, because we\n+ * need the object size, not entry size of the\n+ * array.\n+ */\n+ curr_elem = g_malloc0(field->size);\n+ /* Remember to update the root pointer! */\n+ *(void **)curr_elem_p = curr_elem;\n+ }\n }\n }\n \n@@ -625,13 +623,6 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,\n bool is_null_prev = false;\n bool use_vmdesc = true;\n \n- /*\n- * When this is enabled, it means we will always push a ptr\n- * marker first for each element saying if it's populated.\n- */\n- bool use_dynamic_array =\n- field->flags & VMS_ARRAY_OF_POINTER_AUTO_ALLOC;\n-\n trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems);\n if (field->flags & VMS_POINTER) {\n first_elem = *(void **)first_elem;\n@@ -639,83 +630,83 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,\n }\n \n for (i = 0; i < n_elems; i++) {\n+ bool save_field = true;\n void *curr_elem = first_elem + size * i;\n- const VMStateField *inner_field;\n- bool use_marker_field, is_null = false;\n int max_elems = n_elems - i;\n \n if (field->flags & VMS_ARRAY_OF_POINTER) {\n+ const VMStateField *inner_field;\n+ bool use_marker_field, is_null, use_dynamic_array;\n+\n assert(curr_elem);\n curr_elem = *(void **)curr_elem;\n+\n is_null = !curr_elem;\n- }\n \n- use_marker_field = use_dynamic_array || is_null;\n-\n- if (use_marker_field) {\n- inner_field = vmsd_create_ptr_marker_field(field);\n- } else {\n- inner_field = field;\n- }\n-\n- /*\n- * This logic only matters when dumping VM Desc, and only\n- * when the VMSD field can be compressed.\n- *\n- * Due to the fake nullptr handling above, if there's mixed\n- * null/non-null data, it doesn't make sense to emit a\n- * compressed array representation spanning the entire array\n- * because the field types will be different (e.g. struct\n- * vs. nullptr). Search ahead for the next null/non-null element\n- * and start a new compressed array if found.\n- */\n- if (vmdesc && vmsd_can_compress(field) &&\n- (field->flags & VMS_ARRAY_OF_POINTER) &&\n- is_null != is_null_prev) {\n-\n- is_null_prev = is_null;\n- use_vmdesc = true;\n-\n- for (int j = i + 1; j < n_elems; j++) {\n- void *elem = *(void **)(first_elem + size * j);\n- bool elem_is_null = !elem;\n-\n- if (is_null != elem_is_null) {\n- max_elems = j - i;\n- break;\n- }\n- }\n- }\n-\n- if (use_dynamic_array) {\n- use_vmdesc = true;\n- }\n-\n- ok = vmstate_save_field_with_vmdesc(f, curr_elem, size, vmsd,\n- inner_field,\n- use_vmdesc ? vmdesc : NULL,\n- i, max_elems, errp);\n-\n- /* If we used a fake temp field.. free it now */\n- if (use_marker_field) {\n- g_clear_pointer((gpointer *)&inner_field, g_free);\n- }\n-\n- if (!ok) {\n- goto out;\n- }\n-\n- /*\n- * If we're using dynamic array and the element is\n- * populated, dump the real object right after the marker.\n- */\n- if (use_dynamic_array && curr_elem) {\n /*\n- * NOTE: do not use vmstate_size() here because we want\n- * to dump the real VMSD object now.\n+ * When this is enabled, it means we will always push a ptr\n+ * marker first for each element saying if it's populated.\n */\n+ use_dynamic_array =\n+ field->flags & VMS_ARRAY_OF_POINTER_AUTO_ALLOC;\n+\n+ use_marker_field = use_dynamic_array || is_null;\n+\n+ if (vmdesc && vmsd_can_compress(field)) {\n+ /*\n+ * This logic only matters when dumping VM\n+ * Desc, and only when the VMSD field can be\n+ * compressed.\n+ *\n+ * Due to the fake nullptr handling above, if\n+ * there's mixed null/non-null data, it\n+ * doesn't make sense to emit a compressed\n+ * array representation spanning the entire\n+ * array because the field types will be\n+ * different (e.g. struct vs. nullptr). Search\n+ * ahead for the next null/non-null element\n+ * and start a new compressed array if found.\n+ */\n+ if (is_null != is_null_prev) {\n+ is_null_prev = is_null;\n+ use_vmdesc = true;\n+\n+ for (int j = i + 1; j < n_elems; j++) {\n+ void *elem = *(void **)(first_elem + size * j);\n+ bool elem_is_null = !elem;\n+\n+ if (is_null != elem_is_null) {\n+ max_elems = j - i;\n+ break;\n+ }\n+ }\n+ }\n+ }\n+\n+ if (use_dynamic_array) {\n+ use_vmdesc = true;\n+ }\n+\n+ if (use_marker_field) {\n+ inner_field = vmsd_create_ptr_marker_field(field);\n+\n+ ok = vmstate_save_field_with_vmdesc(\n+ f, curr_elem, 1, vmsd, inner_field,\n+ use_vmdesc ? vmdesc : NULL, i, max_elems, errp);\n+\n+ g_clear_pointer((gpointer *)&inner_field, g_free);\n+\n+ if (!ok) {\n+ goto out;\n+ }\n+\n+ save_field = !!curr_elem;\n+ }\n+ }\n+\n+ if (save_field) {\n ok = vmstate_save_field_with_vmdesc(\n- f, curr_elem, field->size, vmsd, field,\n+ f, curr_elem, size, vmsd, field,\n use_vmdesc ? vmdesc : NULL, i, max_elems, errp);\n \n if (!ok) {\n", "prefixes": [ "RFC", "v1", "06/17" ] }