| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| K. Y. Srinivasan | 4448 | 78.45% | 21 | 39.62% |
| Vitaly Kuznetsov | 957 | 16.88% | 18 | 33.96% |
| Alex Ng | 233 | 4.11% | 8 | 15.09% |
| Dexuan Cui | 15 | 0.26% | 1 | 1.89% |
| Arjan van de Ven | 10 | 0.18% | 1 | 1.89% |
| Nicholas Mc Guire | 3 | 0.05% | 1 | 1.89% |
| Wei Yongjun | 2 | 0.04% | 1 | 1.89% |
| Lance Roy | 1 | 0.02% | 1 | 1.89% |
| Greg Kroah-Hartman | 1 | 0.02% | 1 | 1.89% |
| Total | 5670 | 53 |
/* * Copyright (c) 2012, Microsoft Corporation. * * Author: * K. Y. Srinivasan <kys@microsoft.com> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for more * details. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h> #include <linux/jiffies.h> #include <linux/mman.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/kthread.h> #include <linux/completion.h> #include <linux/memory_hotplug.h> #include <linux/memory.h> #include <linux/notifier.h> #include <linux/percpu_counter.h> #include <linux/hyperv.h> #define CREATE_TRACE_POINTS #include "hv_trace_balloon.h" /* * We begin with definitions supporting the Dynamic Memory protocol * with the host. * * Begin protocol definitions. */ /* * Protocol versions. The low word is the minor version, the high word the major * version. * * History: * Initial version 1.0 * Changed to 0.1 on 2009/03/25 * Changes to 0.2 on 2009/05/14 * Changes to 0.3 on 2009/12/03 * Changed to 1.0 on 2011/04/05 */ #define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor))) #define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16) #define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff) enum { DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3), DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0), DYNMEM_PROTOCOL_VERSION_3 = DYNMEM_MAKE_VERSION(2, 0), DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1, DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2, DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3, DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN10 }; /* * Message Types */ enum dm_message_type { /* * Version 0.3 */ DM_ERROR = 0, DM_VERSION_REQUEST = 1, DM_VERSION_RESPONSE = 2, DM_CAPABILITIES_REPORT = 3, DM_CAPABILITIES_RESPONSE = 4, DM_STATUS_REPORT = 5, DM_BALLOON_REQUEST = 6, DM_BALLOON_RESPONSE = 7, DM_UNBALLOON_REQUEST = 8, DM_UNBALLOON_RESPONSE = 9, DM_MEM_HOT_ADD_REQUEST = 10, DM_MEM_HOT_ADD_RESPONSE = 11, DM_VERSION_03_MAX = 11, /* * Version 1.0. */ DM_INFO_MESSAGE = 12, DM_VERSION_1_MAX = 12 }; /* * Structures defining the dynamic memory management * protocol. */ union dm_version { struct { __u16 minor_version; __u16 major_version; }; __u32 version; } __packed; union dm_caps { struct { __u64 balloon:1; __u64 hot_add:1; /* * To support guests that may have alignment * limitations on hot-add, the guest can specify * its alignment requirements; a value of n * represents an alignment of 2^n in mega bytes. */ __u64 hot_add_alignment:4; __u64 reservedz:58; } cap_bits; __u64 caps; } __packed; union dm_mem_page_range { struct { /* * The PFN number of the first page in the range. * 40 bits is the architectural limit of a PFN * number for AMD64. */ __u64 start_page:40; /* * The number of pages in the range. */ __u64 page_cnt:24; } finfo; __u64 page_range; } __packed; /* * The header for all dynamic memory messages: * * type: Type of the message. * size: Size of the message in bytes; including the header. * trans_id: The guest is responsible for manufacturing this ID. */ struct dm_header { __u16 type; __u16 size; __u32 trans_id; } __packed; /* * A generic message format for dynamic memory. * Specific message formats are defined later in the file. */ struct dm_message { struct dm_header hdr; __u8 data[]; /* enclosed message */ } __packed; /* * Specific message types supporting the dynamic memory protocol. */ /* * Version negotiation message. Sent from the guest to the host. * The guest is free to try different versions until the host * accepts the version. * * dm_version: The protocol version requested. * is_last_attempt: If TRUE, this is the last version guest will request. * reservedz: Reserved field, set to zero. */ struct dm_version_request { struct dm_header hdr; union dm_version version; __u32 is_last_attempt:1; __u32 reservedz:31; } __packed; /* * Version response message; Host to Guest and indicates * if the host has accepted the version sent by the guest. * * is_accepted: If TRUE, host has accepted the version and the guest * should proceed to the next stage of the protocol. FALSE indicates that * guest should re-try with a different version. * * reservedz: Reserved field, set to zero. */ struct dm_version_response { struct dm_header hdr; __u64 is_accepted:1; __u64 reservedz:63; } __packed; /* * Message reporting capabilities. This is sent from the guest to the * host. */ struct dm_capabilities { struct dm_header hdr; union dm_caps caps; __u64 min_page_cnt; __u64 max_page_number; } __packed; /* * Response to the capabilities message. This is sent from the host to the * guest. This message notifies if the host has accepted the guest's * capabilities. If the host has not accepted, the guest must shutdown * the service. * * is_accepted: Indicates if the host has accepted guest's capabilities. * reservedz: Must be 0. */ struct dm_capabilities_resp_msg { struct dm_header hdr; __u64 is_accepted:1; __u64 reservedz:63; } __packed; /* * This message is used to report memory pressure from the guest. * This message is not part of any transaction and there is no * response to this message. * * num_avail: Available memory in pages. * num_committed: Committed memory in pages. * page_file_size: The accumulated size of all page files * in the system in pages. * zero_free: The nunber of zero and free pages. * page_file_writes: The writes to the page file in pages. * io_diff: An indicator of file cache efficiency or page file activity, * calculated as File Cache Page Fault Count - Page Read Count. * This value is in pages. * * Some of these metrics are Windows specific and fortunately * the algorithm on the host side that computes the guest memory * pressure only uses num_committed value. */ struct dm_status { struct dm_header hdr; __u64 num_avail; __u64 num_committed; __u64 page_file_size; __u64 zero_free; __u32 page_file_writes; __u32 io_diff; } __packed; /* * Message to ask the guest to allocate memory - balloon up message. * This message is sent from the host to the guest. The guest may not be * able to allocate as much memory as requested. * * num_pages: number of pages to allocate. */ struct dm_balloon { struct dm_header hdr; __u32 num_pages; __u32 reservedz; } __packed; /* * Balloon response message; this message is sent from the guest * to the host in response to the balloon message. * * reservedz: Reserved; must be set to zero. * more_pages: If FALSE, this is the last message of the transaction. * if TRUE there will atleast one more message from the guest. * * range_count: The number of ranges in the range array. * * range_array: An array of page ranges returned to the host. * */ struct dm_balloon_response { struct dm_header hdr; __u32 reservedz; __u32 more_pages:1; __u32 range_count:31; union dm_mem_page_range range_array[]; } __packed; /* * Un-balloon message; this message is sent from the host * to the guest to give guest more memory. * * more_pages: If FALSE, this is the last message of the transaction. * if TRUE there will atleast one more message from the guest. * * reservedz: Reserved; must be set to zero. * * range_count: The number of ranges in the range array. * * range_array: An array of page ranges returned to the host. * */ struct dm_unballoon_request { struct dm_header hdr; __u32 more_pages:1; __u32 reservedz:31; __u32 range_count; union dm_mem_page_range range_array[]; } __packed; /* * Un-balloon response message; this message is sent from the guest * to the host in response to an unballoon request. * */ struct dm_unballoon_response { struct dm_header hdr; } __packed; /* * Hot add request message. Message sent from the host to the guest. * * mem_range: Memory range to hot add. * * On Linux we currently don't support this since we cannot hot add * arbitrary granularity of memory. */ struct dm_hot_add { struct dm_header hdr; union dm_mem_page_range range; } __packed; /* * Hot add response message. * This message is sent by the guest to report the status of a hot add request. * If page_count is less than the requested page count, then the host should * assume all further hot add requests will fail, since this indicates that * the guest has hit an upper physical memory barrier. * * Hot adds may also fail due to low resources; in this case, the guest must * not complete this message until the hot add can succeed, and the host must * not send a new hot add request until the response is sent. * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS * times it fails the request. * * * page_count: number of pages that were successfully hot added. * * result: result of the operation 1: success, 0: failure. * */ struct dm_hot_add_response { struct dm_header hdr; __u32 page_count; __u32 result; } __packed; /* * Types of information sent from host to the guest. */ enum dm_info_type { INFO_TYPE_MAX_PAGE_CNT = 0, MAX_INFO_TYPE }; /* * Header for the information message. */ struct dm_info_header { enum dm_info_type type; __u32 data_size; } __packed; /* * This message is sent from the host to the guest to pass * some relevant information (win8 addition). * * reserved: no used. * info_size: size of the information blob. * info: information blob. */ struct dm_info_msg { struct dm_header hdr; __u32 reserved; __u32 info_size; __u8 info[]; }; /* * End protocol definitions. */ /* * State to manage hot adding memory into the guest. * The range start_pfn : end_pfn specifies the range * that the host has asked us to hot add. The range * start_pfn : ha_end_pfn specifies the range that we have * currently hot added. We hot add in multiples of 128M * chunks; it is possible that we may not be able to bring * online all the pages in the region. The range * covered_start_pfn:covered_end_pfn defines the pages that can * be brough online. */ struct hv_hotadd_state { struct list_head list; unsigned long start_pfn; unsigned long covered_start_pfn; unsigned long covered_end_pfn; unsigned long ha_end_pfn; unsigned long end_pfn; /* * A list of gaps. */ struct list_head gap_list; }; struct hv_hotadd_gap { struct list_head list; unsigned long start_pfn; unsigned long end_pfn; }; struct balloon_state { __u32 num_pages; struct work_struct wrk; }; struct hot_add_wrk { union dm_mem_page_range ha_page_range; union dm_mem_page_range ha_region_range; struct work_struct wrk; }; static bool hot_add = true; static bool do_hot_add; /* * Delay reporting memory pressure by * the specified number of seconds. */ static uint pressure_report_delay = 45; /* * The last time we posted a pressure report to host. */ static unsigned long last_post_time; module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); static atomic_t trans_id = ATOMIC_INIT(0); static int dm_ring_size = (5 * PAGE_SIZE); /* * Driver specific state. */ enum hv_dm_state { DM_INITIALIZING = 0, DM_INITIALIZED, DM_BALLOON_UP, DM_BALLOON_DOWN, DM_HOT_ADD, DM_INIT_ERROR }; static __u8 recv_buffer[PAGE_SIZE]; static __u8 *send_buffer; #define PAGES_IN_2M 512 #define HA_CHUNK (32 * 1024) struct hv_dynmem_device { struct hv_device *dev; enum hv_dm_state state; struct completion host_event; struct completion config_event; /* * Number of pages we have currently ballooned out. */ unsigned int num_pages_ballooned; unsigned int num_pages_onlined; unsigned int num_pages_added; /* * State to manage the ballooning (up) operation. */ struct balloon_state balloon_wrk; /* * State to execute the "hot-add" operation. */ struct hot_add_wrk ha_wrk; /* * This state tracks if the host has specified a hot-add * region. */ bool host_specified_ha_region; /* * State to synchronize hot-add. */ struct completion ol_waitevent; bool ha_waiting; /* * This thread handles hot-add * requests from the host as well as notifying * the host with regards to memory pressure in * the guest. */ struct task_struct *thread; /* * Protects ha_region_list, num_pages_onlined counter and individual * regions from ha_region_list. */ spinlock_t ha_lock; /* * A list of hot-add regions. */ struct list_head ha_region_list; /* * We start with the highest version we can support * and downgrade based on the host; we save here the * next version to try. */ __u32 next_version; /* * The negotiated version agreed by host. */ __u32 version; }; static struct hv_dynmem_device dm_device; static void post_status(struct hv_dynmem_device *dm); #ifdef CONFIG_MEMORY_HOTPLUG static inline bool has_pfn_is_backed(struct hv_hotadd_state *has, unsigned long pfn) { struct hv_hotadd_gap *gap; /* The page is not backed. */ if ((pfn < has->covered_start_pfn) || (pfn >= has->covered_end_pfn)) return false; /* Check for gaps. */ list_for_each_entry(gap, &has->gap_list, list) { if ((pfn >= gap->start_pfn) && (pfn < gap->end_pfn)) return false; } return true; } static unsigned long hv_page_offline_check(unsigned long start_pfn, unsigned long nr_pages) { unsigned long pfn = start_pfn, count = 0; struct hv_hotadd_state *has; bool found; while (pfn < start_pfn + nr_pages) { /* * Search for HAS which covers the pfn and when we find one * count how many consequitive PFNs are covered. */ found = false; list_for_each_entry(has, &dm_device.ha_region_list, list) { while ((pfn >= has->start_pfn) && (pfn < has->end_pfn) && (pfn < start_pfn + nr_pages)) { found = true; if (has_pfn_is_backed(has, pfn)) count++; pfn++; } } /* * This PFN is not in any HAS (e.g. we're offlining a region * which was present at boot), no need to account for it. Go * to the next one. */ if (!found) pfn++; } return count; } static int hv_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) { struct memory_notify *mem = (struct memory_notify *)v; unsigned long flags, pfn_count; switch (val) { case MEM_ONLINE: case MEM_CANCEL_ONLINE: if (dm_device.ha_waiting) { dm_device.ha_waiting = false; complete(&dm_device.ol_waitevent); } break; case MEM_OFFLINE: spin_lock_irqsave(&dm_device.ha_lock, flags); pfn_count = hv_page_offline_check(mem->start_pfn, mem->nr_pages); if (pfn_count <= dm_device.num_pages_onlined) { dm_device.num_pages_onlined -= pfn_count; } else { /* * We're offlining more pages than we managed to online. * This is unexpected. In any case don't let * num_pages_onlined wrap around zero. */ WARN_ON_ONCE(1); dm_device.num_pages_onlined = 0; } spin_unlock_irqrestore(&dm_device.ha_lock, flags); break; case MEM_GOING_ONLINE: case MEM_GOING_OFFLINE: case MEM_CANCEL_OFFLINE: break; } return NOTIFY_OK; } static struct notifier_block hv_memory_nb = { .notifier_call = hv_memory_notifier, .priority = 0 }; /* Check if the particular page is backed and can be onlined and online it. */ static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg) { if (!has_pfn_is_backed(has, page_to_pfn(pg))) return; /* This frame is currently backed; online the page. */ __online_page_set_limits(pg); __online_page_increment_counters(pg); __online_page_free(pg); lockdep_assert_held(&dm_device.ha_lock); dm_device.num_pages_onlined++; } static void hv_bring_pgs_online(struct hv_hotadd_state *has, unsigned long start_pfn, unsigned long size) { int i; pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn); for (i = 0; i < size; i++) hv_page_online_one(has, pfn_to_page(start_pfn + i)); } static void hv_mem_hot_add(unsigned long start, unsigned long size, unsigned long pfn_count, struct hv_hotadd_state *has) { int ret = 0; int i, nid; unsigned long start_pfn; unsigned long processed_pfn; unsigned long total_pfn = pfn_count; unsigned long flags; for (i = 0; i < (size/HA_CHUNK); i++) { start_pfn = start + (i * HA_CHUNK); spin_lock_irqsave(&dm_device.ha_lock, flags); has->ha_end_pfn += HA_CHUNK; if (total_pfn > HA_CHUNK) { processed_pfn = HA_CHUNK; total_pfn -= HA_CHUNK; } else { processed_pfn = total_pfn; total_pfn = 0; } has->covered_end_pfn += processed_pfn; spin_unlock_irqrestore(&dm_device.ha_lock, flags); init_completion(&dm_device.ol_waitevent); dm_device.ha_waiting = !memhp_auto_online; nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); ret = add_memory(nid, PFN_PHYS((start_pfn)), (HA_CHUNK << PAGE_SHIFT)); if (ret) { pr_err("hot_add memory failed error is %d\n", ret); if (ret == -EEXIST) { /* * This error indicates that the error * is not a transient failure. This is the * case where the guest's physical address map * precludes hot adding memory. Stop all further * memory hot-add. */ do_hot_add = false; } spin_lock_irqsave(&dm_device.ha_lock, flags); has->ha_end_pfn -= HA_CHUNK; has->covered_end_pfn -= processed_pfn; spin_unlock_irqrestore(&dm_device.ha_lock, flags); break; } /* * Wait for the memory block to be onlined when memory onlining * is done outside of kernel (memhp_auto_online). Since the hot * add has succeeded, it is ok to proceed even if the pages in * the hot added region have not been "onlined" within the * allowed time. */ if (dm_device.ha_waiting) wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ); post_status(&dm_device); } } static void hv_online_page(struct page *pg) { struct hv_hotadd_state *has; unsigned long flags; unsigned long pfn = page_to_pfn(pg); spin_lock_irqsave(&dm_device.ha_lock, flags); list_for_each_entry(has, &dm_device.ha_region_list, list) { /* The page belongs to a different HAS. */ if ((pfn < has->start_pfn) || (pfn >= has->end_pfn)) continue; hv_page_online_one(has, pg); break; } spin_unlock_irqrestore(&dm_device.ha_lock, flags); } static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) { struct hv_hotadd_state *has; struct hv_hotadd_gap *gap; unsigned long residual, new_inc; int ret = 0; unsigned long flags; spin_lock_irqsave(&dm_device.ha_lock, flags); list_for_each_entry(has, &dm_device.ha_region_list, list) { /* * If the pfn range we are dealing with is not in the current * "hot add block", move on. */ if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) continue; /* * If the current start pfn is not where the covered_end * is, create a gap and update covered_end_pfn. */ if (has->covered_end_pfn != start_pfn) { gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC); if (!gap) { ret = -ENOMEM; break; } INIT_LIST_HEAD(&gap->list); gap->start_pfn = has->covered_end_pfn; gap->end_pfn = start_pfn; list_add_tail(&gap->list, &has->gap_list); has->covered_end_pfn = start_pfn; } /* * If the current hot add-request extends beyond * our current limit; extend it. */ if ((start_pfn + pfn_cnt) > has->end_pfn) { residual = (start_pfn + pfn_cnt - has->end_pfn); /* * Extend the region by multiples of HA_CHUNK. */ new_inc = (residual / HA_CHUNK) * HA_CHUNK; if (residual % HA_CHUNK) new_inc += HA_CHUNK; has->end_pfn += new_inc; } ret = 1; break; } spin_unlock_irqrestore(&dm_device.ha_lock, flags); return ret; } static unsigned long handle_pg_range(unsigned long pg_start, unsigned long pg_count) { unsigned long start_pfn = pg_start; unsigned long pfn_cnt = pg_count; unsigned long size; struct hv_hotadd_state *has; unsigned long pgs_ol = 0; unsigned long old_covered_state; unsigned long res = 0, flags; pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count, pg_start); spin_lock_irqsave(&dm_device.ha_lock, flags); list_for_each_entry(has, &dm_device.ha_region_list, list) { /* * If the pfn range we are dealing with is not in the current * "hot add block", move on. */ if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) continue; old_covered_state = has->covered_end_pfn; if (start_pfn < has->ha_end_pfn) { /* * This is the case where we are backing pages * in an already hot added region. Bring * these pages online first. */ pgs_ol = has->ha_end_pfn - start_pfn; if (pgs_ol > pfn_cnt) pgs_ol = pfn_cnt; has->covered_end_pfn += pgs_ol; pfn_cnt -= pgs_ol; /* * Check if the corresponding memory block is already * online by checking its last previously backed page. * In case it is we need to bring rest (which was not * backed previously) online too. */ if (start_pfn > has->start_pfn && !PageReserved(pfn_to_page(start_pfn - 1))) hv_bring_pgs_online(has, start_pfn, pgs_ol); } if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) { /* * We have some residual hot add range * that needs to be hot added; hot add * it now. Hot add a multiple of * of HA_CHUNK that fully covers the pages * we have. */ size = (has->end_pfn - has->ha_end_pfn); if (pfn_cnt <= size) { size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK); if (pfn_cnt % HA_CHUNK) size += HA_CHUNK; } else { pfn_cnt = size; } spin_unlock_irqrestore(&dm_device.ha_lock, flags); hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); spin_lock_irqsave(&dm_device.ha_lock, flags); } /* * If we managed to online any pages that were given to us, * we declare success. */ res = has->covered_end_pfn - old_covered_state; break; } spin_unlock_irqrestore(&dm_device.ha_lock, flags); return res; } static unsigned long process_hot_add(unsigned long pg_start, unsigned long pfn_cnt, unsigned long rg_start, unsigned long rg_size) { struct hv_hotadd_state *ha_region = NULL; int covered; unsigned long flags; if (pfn_cnt == 0) return 0; if (!dm_device.host_specified_ha_region) { covered = pfn_covered(pg_start, pfn_cnt); if (covered < 0) return 0; if (covered) goto do_pg_range; } /* * If the host has specified a hot-add range; deal with it first. */ if (rg_size != 0) { ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL); if (!ha_region) return 0; INIT_LIST_HEAD(&ha_region->list); INIT_LIST_HEAD(&ha_region->gap_list); ha_region->start_pfn = rg_start; ha_region->ha_end_pfn = rg_start; ha_region->covered_start_pfn = pg_start; ha_region->covered_end_pfn = pg_start; ha_region->end_pfn = rg_start + rg_size; spin_lock_irqsave(&dm_device.ha_lock, flags); list_add_tail(&ha_region->list, &dm_device.ha_region_list); spin_unlock_irqrestore(&dm_device.ha_lock, flags); } do_pg_range: /* * Process the page range specified; bringing them * online if possible. */ return handle_pg_range(pg_start, pfn_cnt); } #endif static void hot_add_req(struct work_struct *dummy) { struct dm_hot_add_response resp; #ifdef CONFIG_MEMORY_HOTPLUG unsigned long pg_start, pfn_cnt; unsigned long rg_start, rg_sz; #endif struct hv_dynmem_device *dm = &dm_device; memset(&resp, 0, sizeof(struct dm_hot_add_response)); resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; resp.hdr.size = sizeof(struct dm_hot_add_response); #ifdef CONFIG_MEMORY_HOTPLUG pg_start = dm->ha_wrk.ha_page_range.finfo.start_page; pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt; rg_start = dm->ha_wrk.ha_region_range.finfo.start_page; rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt; if ((rg_start == 0) && (!dm->host_specified_ha_region)) { unsigned long region_size; unsigned long region_start; /* * The host has not specified the hot-add region. * Based on the hot-add page range being specified, * compute a hot-add region that can cover the pages * that need to be hot-added while ensuring the alignment * and size requirements of Linux as it relates to hot-add. */ region_start = pg_start; region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK; if (pfn_cnt % HA_CHUNK) region_size += HA_CHUNK; region_start = (pg_start / HA_CHUNK) * HA_CHUNK; rg_start = region_start; rg_sz = region_size; } if (do_hot_add) resp.page_count = process_hot_add(pg_start, pfn_cnt, rg_start, rg_sz); dm->num_pages_added += resp.page_count; #endif /* * The result field of the response structure has the * following semantics: * * 1. If all or some pages hot-added: Guest should return success. * * 2. If no pages could be hot-added: * * If the guest returns success, then the host * will not attempt any further hot-add operations. This * signifies a permanent failure. * * If the guest returns failure, then this failure will be * treated as a transient failure and the host may retry the * hot-add operation after some delay. */ if (resp.page_count > 0) resp.result = 1; else if (!do_hot_add) resp.result = 1; else resp.result = 0; if (!do_hot_add || (resp.page_count == 0)) pr_err("Memory hot add failed\n"); dm->state = DM_INITIALIZED; resp.hdr.trans_id = atomic_inc_return(&trans_id); vmbus_sendpacket(dm->dev->channel, &resp, sizeof(struct dm_hot_add_response), (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); } static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) { struct dm_info_header *info_hdr; info_hdr = (struct dm_info_header *)msg->info; switch (info_hdr->type) { case INFO_TYPE_MAX_PAGE_CNT: if (info_hdr->data_size == sizeof(__u64)) { __u64 *max_page_count = (__u64 *)&info_hdr[1]; pr_info("Max. dynamic memory size: %llu MB\n", (*max_page_count) >> (20 - PAGE_SHIFT)); } break; default: pr_warn("Received Unknown type: %d\n", info_hdr->type); } } static unsigned long compute_balloon_floor(void) { unsigned long min_pages; #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) /* Simple continuous piecewiese linear function: * max MiB -> min MiB gradient * 0 0 * 16 16 * 32 24 * 128 72 (1/2) * 512 168 (1/4) * 2048 360 (1/8) * 8192 744 (1/16) * 32768 1512 (1/32) */ if (totalram_pages < MB2PAGES(128)) min_pages = MB2PAGES(8) + (totalram_pages >> 1); else if (totalram_pages < MB2PAGES(512)) min_pages = MB2PAGES(40) + (totalram_pages >> 2); else if (totalram_pages < MB2PAGES(2048)) min_pages = MB2PAGES(104) + (totalram_pages >> 3); else if (totalram_pages < MB2PAGES(8192)) min_pages = MB2PAGES(232) + (totalram_pages >> 4); else min_pages = MB2PAGES(488) + (totalram_pages >> 5); #undef MB2PAGES return min_pages; } /* * Post our status as it relates memory pressure to the * host. Host expects the guests to post this status * periodically at 1 second intervals. * * The metrics specified in this protocol are very Windows * specific and so we cook up numbers here to convey our memory * pressure. */ static void post_status(struct hv_dynmem_device *dm) { struct dm_status status; unsigned long now = jiffies; unsigned long last_post = last_post_time; if (pressure_report_delay > 0) { --pressure_report_delay; return; } if (!time_after(now, (last_post_time + HZ))) return; memset(&status, 0, sizeof(struct dm_status)); status.hdr.type = DM_STATUS_REPORT; status.hdr.size = sizeof(struct dm_status); status.hdr.trans_id = atomic_inc_return(&trans_id); /* * The host expects the guest to report free and committed memory. * Furthermore, the host expects the pressure information to include * the ballooned out pages. For a given amount of memory that we are * managing we need to compute a floor below which we should not * balloon. Compute this and add it to the pressure report. * We also need to report all offline pages (num_pages_added - * num_pages_onlined) as committed to the host, otherwise it can try * asking us to balloon them out. */ status.num_avail = si_mem_available(); status.num_committed = vm_memory_committed() + dm->num_pages_ballooned + (dm->num_pages_added > dm->num_pages_onlined ? dm->num_pages_added - dm->num_pages_onlined : 0) + compute_balloon_floor(); trace_balloon_status(status.num_avail, status.num_committed, vm_memory_committed(), dm->num_pages_ballooned, dm->num_pages_added, dm->num_pages_onlined); /* * If our transaction ID is no longer current, just don't * send the status. This can happen if we were interrupted * after we picked our transaction ID. */ if (status.hdr.trans_id != atomic_read(&trans_id)) return; /* * If the last post time that we sampled has changed, * we have raced, don't post the status. */ if (last_post != last_post_time) return; last_post_time = jiffies; vmbus_sendpacket(dm->dev->channel, &status, sizeof(struct dm_status), (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); } static void free_balloon_pages(struct hv_dynmem_device *dm, union dm_mem_page_range *range_array) { int num_pages = range_array->finfo.page_cnt; __u64 start_frame = range_array->finfo.start_page; struct page *pg; int i; for (i = 0; i < num_pages; i++) { pg = pfn_to_page(i + start_frame); __free_page(pg); dm->num_pages_ballooned--; } } static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm, unsigned int num_pages, struct dm_balloon_response *bl_resp, int alloc_unit) { unsigned int i = 0; struct page *pg; if (num_pages < alloc_unit) return 0; for (i = 0; (i * alloc_unit) < num_pages; i++) { if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > PAGE_SIZE) return i * alloc_unit; /* * We execute this code in a thread context. Furthermore, * we don't want the kernel to try too hard. */ pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN, get_order(alloc_unit << PAGE_SHIFT)); if (!pg) return i * alloc_unit; dm->num_pages_ballooned += alloc_unit; /* * If we allocatted 2M pages; split them so we * can free them in any order we get. */ if (alloc_unit != 1) split_page(pg, get_order(alloc_unit << PAGE_SHIFT)); bl_resp->range_count++; bl_resp->range_array[i].finfo.start_page = page_to_pfn(pg); bl_resp->range_array[i].finfo.page_cnt = alloc_unit; bl_resp->hdr.size += sizeof(union dm_mem_page_range); } return num_pages; } static void balloon_up(struct work_struct *dummy) { unsigned int num_pages = dm_device.balloon_wrk.num_pages; unsigned int num_ballooned = 0; struct dm_balloon_response *bl_resp; int alloc_unit; int ret; bool done = false; int i; long avail_pages; unsigned long floor; /* The host balloons pages in 2M granularity. */ WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0); /* * We will attempt 2M allocations. However, if we fail to * allocate 2M chunks, we will go back to 4k allocations. */ alloc_unit = 512; avail_pages = si_mem_available(); floor = compute_balloon_floor(); /* Refuse to balloon below the floor, keep the 2M granularity. */ if (avail_pages < num_pages || avail_pages - num_pages < floor) { pr_warn("Balloon request will be partially fulfilled. %s\n", avail_pages < num_pages ? "Not enough memory." : "Balloon floor reached."); num_pages = avail_pages > floor ? (avail_pages - floor) : 0; num_pages -= num_pages % PAGES_IN_2M; } while (!done) { bl_resp = (struct dm_balloon_response *)send_buffer; memset(send_buffer, 0, PAGE_SIZE); bl_resp->hdr.type = DM_BALLOON_RESPONSE; bl_resp->hdr.size = sizeof(struct dm_balloon_response); bl_resp->more_pages = 1; num_pages -= num_ballooned; num_ballooned = alloc_balloon_pages(&dm_device, num_pages, bl_resp, alloc_unit); if (alloc_unit != 1 && num_ballooned == 0) { alloc_unit = 1; continue; } if (num_ballooned == 0 || num_ballooned == num_pages) { pr_debug("Ballooned %u out of %u requested pages.\n", num_pages, dm_device.balloon_wrk.num_pages); bl_resp->more_pages = 0; done = true; dm_device.state = DM_INITIALIZED; } /* * We are pushing a lot of data through the channel; * deal with transient failures caused because of the * lack of space in the ring buffer. */ do { bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); ret = vmbus_sendpacket(dm_device.dev->channel, bl_resp, bl_resp->hdr.size, (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); if (ret == -EAGAIN) msleep(20); post_status(&dm_device); } while (ret == -EAGAIN); if (ret) { /* * Free up the memory we allocatted. */ pr_err("Balloon response failed\n"); for (i = 0; i < bl_resp->range_count; i++) free_balloon_pages(&dm_device, &bl_resp->range_array[i]); done = true; } } } static void balloon_down(struct hv_dynmem_device *dm, struct dm_unballoon_request *req) { union dm_mem_page_range *range_array = req->range_array; int range_count = req->range_count; struct dm_unballoon_response resp; int i; unsigned int prev_pages_ballooned = dm->num_pages_ballooned; for (i = 0; i < range_count; i++) { free_balloon_pages(dm, &range_array[i]); complete(&dm_device.config_event); } pr_debug("Freed %u ballooned pages.\n", prev_pages_ballooned - dm->num_pages_ballooned); if (req->more_pages == 1) return; memset(&resp, 0, sizeof(struct dm_unballoon_response)); resp.hdr.type = DM_UNBALLOON_RESPONSE; resp.hdr.trans_id = atomic_inc_return(&trans_id); resp.hdr.size = sizeof(struct dm_unballoon_response); vmbus_sendpacket(dm_device.dev->channel, &resp, sizeof(struct dm_unballoon_response), (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); dm->state = DM_INITIALIZED; } static void balloon_onchannelcallback(void *context); static int dm_thread_func(void *dm_dev) { struct hv_dynmem_device *dm = dm_dev; while (!kthread_should_stop()) { wait_for_completion_interruptible_timeout( &dm_device.config_event, 1*HZ); /* * The host expects us to post information on the memory * pressure every second. */ reinit_completion(&dm_device.config_event); post_status(dm); } return 0; } static void version_resp(struct hv_dynmem_device *dm, struct dm_version_response *vresp) { struct dm_version_request version_req; int ret; if (vresp->is_accepted) { /* * We are done; wakeup the * context waiting for version * negotiation. */ complete(&dm->host_event); return; } /* * If there are more versions to try, continue * with negotiations; if not * shutdown the service since we are not able * to negotiate a suitable version number * with the host. */ if (dm->next_version == 0) goto version_error; memset(&version_req, 0, sizeof(struct dm_version_request)); version_req.hdr.type = DM_VERSION_REQUEST; version_req.hdr.size = sizeof(struct dm_version_request); version_req.hdr.trans_id = atomic_inc_return(&trans_id); version_req.version.version = dm->next_version; dm->version = version_req.version.version; /* * Set the next version to try in case current version fails. * Win7 protocol ought to be the last one to try. */ switch (version_req.version.version) { case DYNMEM_PROTOCOL_VERSION_WIN8: dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7; version_req.is_last_attempt = 0; break; default: dm->next_version = 0; version_req.is_last_attempt = 1; } ret = vmbus_sendpacket(dm->dev->channel, &version_req, sizeof(struct dm_version_request), (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); if (ret) goto version_error; return; version_error: dm->state = DM_INIT_ERROR; complete(&dm->host_event); } static void cap_resp(struct hv_dynmem_device *dm, struct dm_capabilities_resp_msg *cap_resp) { if (!cap_resp->is_accepted) { pr_err("Capabilities not accepted by host\n"); dm->state = DM_INIT_ERROR; } complete(&dm->host_event); } static void balloon_onchannelcallback(void *context) { struct hv_device *dev = context; u32 recvlen; u64 requestid; struct dm_message *dm_msg; struct dm_header *dm_hdr; struct hv_dynmem_device *dm = hv_get_drvdata(dev); struct dm_balloon *bal_msg; struct dm_hot_add *ha_msg; union dm_mem_page_range *ha_pg_range; union dm_mem_page_range *ha_region; memset(recv_buffer, 0, sizeof(recv_buffer)); vmbus_recvpacket(dev->channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid); if (recvlen > 0) { dm_msg = (struct dm_message *)recv_buffer; dm_hdr = &dm_msg->hdr; switch (dm_hdr->type) { case DM_VERSION_RESPONSE: version_resp(dm, (struct dm_version_response *)dm_msg); break; case DM_CAPABILITIES_RESPONSE: cap_resp(dm, (struct dm_capabilities_resp_msg *)dm_msg); break; case DM_BALLOON_REQUEST: if (dm->state == DM_BALLOON_UP) pr_warn("Currently ballooning\n"); bal_msg = (struct dm_balloon *)recv_buffer; dm->state = DM_BALLOON_UP; dm_device.balloon_wrk.num_pages = bal_msg->num_pages; schedule_work(&dm_device.balloon_wrk.wrk); break; case DM_UNBALLOON_REQUEST: dm->state = DM_BALLOON_DOWN; balloon_down(dm, (struct dm_unballoon_request *)recv_buffer); break; case DM_MEM_HOT_ADD_REQUEST: if (dm->state == DM_HOT_ADD) pr_warn("Currently hot-adding\n"); dm->state = DM_HOT_ADD; ha_msg = (struct dm_hot_add *)recv_buffer; if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) { /* * This is a normal hot-add request specifying * hot-add memory. */ dm->host_specified_ha_region = false; ha_pg_range = &ha_msg->range; dm->ha_wrk.ha_page_range = *ha_pg_range; dm->ha_wrk.ha_region_range.page_range = 0; } else { /* * Host is specifying that we first hot-add * a region and then partially populate this * region. */ dm->host_specified_ha_region = true; ha_pg_range = &ha_msg->range; ha_region = &ha_pg_range[1]; dm->ha_wrk.ha_page_range = *ha_pg_range; dm->ha_wrk.ha_region_range = *ha_region; } schedule_work(&dm_device.ha_wrk.wrk); break; case DM_INFO_MESSAGE: process_info(dm, (struct dm_info_msg *)dm_msg); break; default: pr_warn("Unhandled message: type: %d\n", dm_hdr->type); } } } static int balloon_probe(struct hv_device *dev, const struct hv_vmbus_device_id *dev_id) { int ret; unsigned long t; struct dm_version_request version_req; struct dm_capabilities cap_msg; #ifdef CONFIG_MEMORY_HOTPLUG do_hot_add = hot_add; #else do_hot_add = false; #endif /* * First allocate a send buffer. */ send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!send_buffer) return -ENOMEM; ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, balloon_onchannelcallback, dev); if (ret) goto probe_error0; dm_device.dev = dev; dm_device.state = DM_INITIALIZING; dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8; init_completion(&dm_device.host_event); init_completion(&dm_device.config_event); INIT_LIST_HEAD(&dm_device.ha_region_list); spin_lock_init(&dm_device.ha_lock); INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up); INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req); dm_device.host_specified_ha_region = false; dm_device.thread = kthread_run(dm_thread_func, &dm_device, "hv_balloon"); if (IS_ERR(dm_device.thread)) { ret = PTR_ERR(dm_device.thread); goto probe_error1; } #ifdef CONFIG_MEMORY_HOTPLUG set_online_page_callback(&hv_online_page); register_memory_notifier(&hv_memory_nb); #endif hv_set_drvdata(dev, &dm_device); /* * Initiate the hand shake with the host and negotiate * a version that the host can support. We start with the * highest version number and go down if the host cannot * support it. */ memset(&version_req, 0, sizeof(struct dm_version_request)); version_req.hdr.type = DM_VERSION_REQUEST; version_req.hdr.size = sizeof(struct dm_version_request); version_req.hdr.trans_id = atomic_inc_return(&trans_id); version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10; version_req.is_last_attempt = 0; dm_device.version = version_req.version.version; ret = vmbus_sendpacket(dev->channel, &version_req, sizeof(struct dm_version_request), (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); if (ret) goto probe_error2; t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); if (t == 0) { ret = -ETIMEDOUT; goto probe_error2; } /* * If we could not negotiate a compatible version with the host * fail the probe function. */ if (dm_device.state == DM_INIT_ERROR) { ret = -ETIMEDOUT; goto probe_error2; } pr_info("Using Dynamic Memory protocol version %u.%u\n", DYNMEM_MAJOR_VERSION(dm_device.version), DYNMEM_MINOR_VERSION(dm_device.version)); /* * Now submit our capabilities to the host. */ memset(&cap_msg, 0, sizeof(struct dm_capabilities)); cap_msg.hdr.type = DM_CAPABILITIES_REPORT; cap_msg.hdr.size = sizeof(struct dm_capabilities); cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); cap_msg.caps.cap_bits.balloon = 1; cap_msg.caps.cap_bits.hot_add = 1; /* * Specify our alignment requirements as it relates * memory hot-add. Specify 128MB alignment. */ cap_msg.caps.cap_bits.hot_add_alignment = 7; /* * Currently the host does not use these * values and we set them to what is done in the * Windows driver. */ cap_msg.min_page_cnt = 0; cap_msg.max_page_number = -1; ret = vmbus_sendpacket(dev->channel, &cap_msg, sizeof(struct dm_capabilities), (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); if (ret) goto probe_error2; t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); if (t == 0) { ret = -ETIMEDOUT; goto probe_error2; } /* * If the host does not like our capabilities, * fail the probe function. */ if (dm_device.state == DM_INIT_ERROR) { ret = -ETIMEDOUT; goto probe_error2; } dm_device.state = DM_INITIALIZED; last_post_time = jiffies; return 0; probe_error2: #ifdef CONFIG_MEMORY_HOTPLUG restore_online_page_callback(&hv_online_page); #endif kthread_stop(dm_device.thread); probe_error1: vmbus_close(dev->channel); probe_error0: kfree(send_buffer); return ret; } static int balloon_remove(struct hv_device *dev) { struct hv_dynmem_device *dm = hv_get_drvdata(dev); struct hv_hotadd_state *has, *tmp; struct hv_hotadd_gap *gap, *tmp_gap; unsigned long flags; if (dm->num_pages_ballooned != 0) pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); cancel_work_sync(&dm->balloon_wrk.wrk); cancel_work_sync(&dm->ha_wrk.wrk); vmbus_close(dev->channel); kthread_stop(dm->thread); kfree(send_buffer); #ifdef CONFIG_MEMORY_HOTPLUG restore_online_page_callback(&hv_online_page); unregister_memory_notifier(&hv_memory_nb); #endif spin_lock_irqsave(&dm_device.ha_lock, flags); list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) { list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) { list_del(&gap->list); kfree(gap); } list_del(&has->list); kfree(has); } spin_unlock_irqrestore(&dm_device.ha_lock, flags); return 0; } static const struct hv_vmbus_device_id id_table[] = { /* Dynamic Memory Class ID */ /* 525074DC-8985-46e2-8057-A307DC18A502 */ { HV_DM_GUID, }, { }, }; MODULE_DEVICE_TABLE(vmbus, id_table); static struct hv_driver balloon_drv = { .name = "hv_balloon", .id_table = id_table, .probe = balloon_probe, .remove = balloon_remove, .driver = { .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, }; static int __init init_balloon_drv(void) { return vmbus_driver_register(&balloon_drv); } module_init(init_balloon_drv); MODULE_DESCRIPTION("Hyper-V Balloon"); MODULE_LICENSE("GPL");
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