diff options
Diffstat (limited to 'drivers/misc/vmw_balloon.c')
| -rw-r--r-- | drivers/misc/vmw_balloon.c | 181 |
1 files changed, 54 insertions, 127 deletions
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 56c6f79a5c5a..2543ef1ece17 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -1,27 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0 /* * VMware Balloon driver. * - * Copyright (C) 2000-2014, VMware, Inc. All Rights Reserved. + * Copyright (C) 2000-2018, VMware, Inc. All Rights Reserved. * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License as published by the - * Free Software Foundation; version 2 of the License and no later version. - * - * 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. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. - * - * Maintained by: Xavier Deguillard <xdeguillard@vmware.com> - * Philip Moltmann <moltmann@vmware.com> - */ - -/* * This is VMware physical memory management driver for Linux. The driver * acts like a "balloon" that can be inflated to reclaim physical pages by * reserving them in the guest and invalidating them in the monitor, @@ -55,25 +37,6 @@ MODULE_ALIAS("vmware_vmmemctl"); MODULE_LICENSE("GPL"); /* - * Various constants controlling rate of inflaint/deflating balloon, - * measured in pages. - */ - -/* - * Rates of memory allocaton when guest experiences memory pressure - * (driver performs sleeping allocations). - */ -#define VMW_BALLOON_RATE_ALLOC_MIN 512U -#define VMW_BALLOON_RATE_ALLOC_MAX 2048U -#define VMW_BALLOON_RATE_ALLOC_INC 16U - -/* - * When guest is under memory pressure, use a reduced page allocation - * rate for next several cycles. - */ -#define VMW_BALLOON_SLOW_CYCLES 4 - -/* * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't * allow wait (__GFP_RECLAIM) for NOSLEEP page allocations. Use * __GFP_NOWARN, to suppress page allocation failure warnings. @@ -284,12 +247,6 @@ struct vmballoon { /* reset flag */ bool reset_required; - /* adjustment rates (pages per second) */ - unsigned int rate_alloc; - - /* slowdown page allocations for next few cycles */ - unsigned int slow_allocation_cycles; - unsigned long capabilities; struct vmballoon_batch_page *batch_page; @@ -341,7 +298,13 @@ static bool vmballoon_send_start(struct vmballoon *b, unsigned long req_caps) success = false; } - if (b->capabilities & VMW_BALLOON_BATCHED_2M_CMDS) + /* + * 2MB pages are only supported with batching. If batching is for some + * reason disabled, do not use 2MB pages, since otherwise the legacy + * mechanism is used with 2MB pages, causing a failure. + */ + if ((b->capabilities & VMW_BALLOON_BATCHED_2M_CMDS) && + (b->capabilities & VMW_BALLOON_BATCHED_CMDS)) b->supported_page_sizes = 2; else b->supported_page_sizes = 1; @@ -450,7 +413,7 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn, pfn32 = (u32)pfn; if (pfn32 != pfn) - return -1; + return -EINVAL; STATS_INC(b->stats.lock[false]); @@ -460,7 +423,7 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn, pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); STATS_INC(b->stats.lock_fail[false]); - return 1; + return -EIO; } static int vmballoon_send_batched_lock(struct vmballoon *b, @@ -597,11 +560,12 @@ static int vmballoon_lock_page(struct vmballoon *b, unsigned int num_pages, locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status, target); - if (locked > 0) { + if (locked) { STATS_INC(b->stats.refused_alloc[false]); - if (hv_status == VMW_BALLOON_ERROR_RESET || - hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED) { + if (locked == -EIO && + (hv_status == VMW_BALLOON_ERROR_RESET || + hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED)) { vmballoon_free_page(page, false); return -EIO; } @@ -617,7 +581,7 @@ static int vmballoon_lock_page(struct vmballoon *b, unsigned int num_pages, } else { vmballoon_free_page(page, false); } - return -EIO; + return locked; } /* track allocated page */ @@ -790,8 +754,6 @@ static void vmballoon_add_batched_page(struct vmballoon *b, int idx, */ static void vmballoon_inflate(struct vmballoon *b) { - unsigned rate; - unsigned int allocations = 0; unsigned int num_pages = 0; int error = 0; gfp_t flags = VMW_PAGE_ALLOC_NOSLEEP; @@ -818,17 +780,9 @@ static void vmballoon_inflate(struct vmballoon *b) * Start with no sleep allocation rate which may be higher * than sleeping allocation rate. */ - if (b->slow_allocation_cycles) { - rate = b->rate_alloc; - is_2m_pages = false; - } else { - rate = UINT_MAX; - is_2m_pages = - b->supported_page_sizes == VMW_BALLOON_NUM_PAGE_SIZES; - } + is_2m_pages = b->supported_page_sizes == VMW_BALLOON_NUM_PAGE_SIZES; - pr_debug("%s - goal: %d, no-sleep rate: %u, sleep rate: %d\n", - __func__, b->target - b->size, rate, b->rate_alloc); + pr_debug("%s - goal: %d", __func__, b->target - b->size); while (!b->reset_required && b->size + num_pages * vmballoon_page_size(is_2m_pages) @@ -861,31 +815,24 @@ static void vmballoon_inflate(struct vmballoon *b) if (flags == VMW_PAGE_ALLOC_CANSLEEP) { /* * CANSLEEP page allocation failed, so guest - * is under severe memory pressure. Quickly - * decrease allocation rate. + * is under severe memory pressure. We just log + * the event, but do not stop the inflation + * due to its negative impact on performance. */ - b->rate_alloc = max(b->rate_alloc / 2, - VMW_BALLOON_RATE_ALLOC_MIN); STATS_INC(b->stats.sleep_alloc_fail); break; } /* * NOSLEEP page allocation failed, so the guest is - * under memory pressure. Let us slow down page - * allocations for next few cycles so that the guest - * gets out of memory pressure. Also, if we already - * allocated b->rate_alloc pages, let's pause, - * otherwise switch to sleeping allocations. + * under memory pressure. Slowing down page alloctions + * seems to be reasonable, but doing so might actually + * cause the hypervisor to throttle us down, resulting + * in degraded performance. We will count on the + * scheduler and standard memory management mechanisms + * for now. */ - b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES; - - if (allocations >= b->rate_alloc) - break; - flags = VMW_PAGE_ALLOC_CANSLEEP; - /* Lower rate for sleeping allocations. */ - rate = b->rate_alloc; continue; } @@ -899,28 +846,11 @@ static void vmballoon_inflate(struct vmballoon *b) } cond_resched(); - - if (allocations >= rate) { - /* We allocated enough pages, let's take a break. */ - break; - } } if (num_pages > 0) b->ops->lock(b, num_pages, is_2m_pages, &b->target); - /* - * We reached our goal without failures so try increasing - * allocation rate. - */ - if (error == 0 && allocations >= b->rate_alloc) { - unsigned int mult = allocations / b->rate_alloc; - - b->rate_alloc = - min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC, - VMW_BALLOON_RATE_ALLOC_MAX); - } - vmballoon_release_refused_pages(b, true); vmballoon_release_refused_pages(b, false); } @@ -1029,29 +959,30 @@ static void vmballoon_vmci_cleanup(struct vmballoon *b) */ static int vmballoon_vmci_init(struct vmballoon *b) { - int error = 0; + unsigned long error, dummy; - if ((b->capabilities & VMW_BALLOON_SIGNALLED_WAKEUP_CMD) != 0) { - error = vmci_doorbell_create(&b->vmci_doorbell, - VMCI_FLAG_DELAYED_CB, - VMCI_PRIVILEGE_FLAG_RESTRICTED, - vmballoon_doorbell, b); - - if (error == VMCI_SUCCESS) { - VMWARE_BALLOON_CMD(VMCI_DOORBELL_SET, - b->vmci_doorbell.context, - b->vmci_doorbell.resource, error); - STATS_INC(b->stats.doorbell_set); - } - } + if ((b->capabilities & VMW_BALLOON_SIGNALLED_WAKEUP_CMD) == 0) + return 0; - if (error != 0) { - vmballoon_vmci_cleanup(b); + error = vmci_doorbell_create(&b->vmci_doorbell, VMCI_FLAG_DELAYED_CB, + VMCI_PRIVILEGE_FLAG_RESTRICTED, + vmballoon_doorbell, b); - return -EIO; - } + if (error != VMCI_SUCCESS) + goto fail; + + error = VMWARE_BALLOON_CMD(VMCI_DOORBELL_SET, b->vmci_doorbell.context, + b->vmci_doorbell.resource, dummy); + + STATS_INC(b->stats.doorbell_set); + + if (error != VMW_BALLOON_SUCCESS) + goto fail; return 0; +fail: + vmballoon_vmci_cleanup(b); + return -EIO; } /* @@ -1114,9 +1045,6 @@ static void vmballoon_work(struct work_struct *work) if (b->reset_required) vmballoon_reset(b); - if (b->slow_allocation_cycles > 0) - b->slow_allocation_cycles--; - if (!b->reset_required && vmballoon_send_get_target(b, &target)) { /* update target, adjust size */ b->target = target; @@ -1160,11 +1088,6 @@ static int vmballoon_debug_show(struct seq_file *f, void *offset) "current: %8d pages\n", b->target, b->size); - /* format rate info */ - seq_printf(f, - "rateSleepAlloc: %8d pages/sec\n", - b->rate_alloc); - seq_printf(f, "\n" "timer: %8u\n" @@ -1271,9 +1194,6 @@ static int __init vmballoon_init(void) INIT_LIST_HEAD(&balloon.page_sizes[is_2m_pages].refused_pages); } - /* initialize rates */ - balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX; - INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work); error = vmballoon_debugfs_init(&balloon); @@ -1289,7 +1209,14 @@ static int __init vmballoon_init(void) return 0; } -module_init(vmballoon_init); + +/* + * Using late_initcall() instead of module_init() allows the balloon to use the + * VMCI doorbell even when the balloon is built into the kernel. Otherwise the + * VMCI is probed only after the balloon is initialized. If the balloon is used + * as a module, late_initcall() is equivalent to module_init(). + */ +late_initcall(vmballoon_init); static void __exit vmballoon_exit(void) { |