--- zzzz-none-000/linux-3.10.107/drivers/xen/balloon.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/drivers/xen/balloon.c 2021-02-04 17:41:59.000000000 +0000 @@ -36,6 +36,9 @@ * IN THE SOFTWARE. */ +#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt + +#include #include #include #include @@ -50,6 +53,9 @@ #include #include #include +#include +#include +#include #include #include @@ -66,16 +72,64 @@ #include #include +static int xen_hotplug_unpopulated; + +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + +static int zero; +static int one = 1; + +static struct ctl_table balloon_table[] = { + { + .procname = "hotplug_unpopulated", + .data = &xen_hotplug_unpopulated, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, + { } +}; + +static struct ctl_table balloon_root[] = { + { + .procname = "balloon", + .mode = 0555, + .child = balloon_table, + }, + { } +}; + +static struct ctl_table xen_root[] = { + { + .procname = "xen", + .mode = 0555, + .child = balloon_root, + }, + { } +}; + +#endif + +/* + * Use one extent per PAGE_SIZE to avoid to break down the page into + * multiple frame. + */ +#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1) + /* * balloon_process() state: * * BP_DONE: done or nothing to do, + * BP_WAIT: wait to be rescheduled, * BP_EAGAIN: error, go to sleep, * BP_ECANCELED: error, balloon operation canceled. */ enum bp_state { BP_DONE, + BP_WAIT, BP_EAGAIN, BP_ECANCELED }; @@ -87,18 +141,12 @@ EXPORT_SYMBOL_GPL(balloon_stats); /* We increase/decrease in batches which fit in a page */ -static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; +static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)]; -#ifdef CONFIG_HIGHMEM -#define inc_totalhigh_pages() (totalhigh_pages++) -#define dec_totalhigh_pages() (totalhigh_pages--) -#else -#define inc_totalhigh_pages() do {} while (0) -#define dec_totalhigh_pages() do {} while (0) -#endif /* List of ballooned pages, threaded through the mem_map array. */ static LIST_HEAD(ballooned_pages); +static DECLARE_WAIT_QUEUE_HEAD(balloon_wq); /* Main work function, always executed in process context. */ static void balloon_process(struct work_struct *work); @@ -127,48 +175,38 @@ list_add(&page->lru, &ballooned_pages); balloon_stats.balloon_low++; } + wake_up(&balloon_wq); } static void balloon_append(struct page *page) { __balloon_append(page); - if (PageHighMem(page)) - dec_totalhigh_pages(); - totalram_pages--; + adjust_managed_page_count(page, -1); } /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ -static struct page *balloon_retrieve(bool prefer_highmem) +static struct page *balloon_retrieve(bool require_lowmem) { struct page *page; if (list_empty(&ballooned_pages)) return NULL; - if (prefer_highmem) - page = list_entry(ballooned_pages.prev, struct page, lru); - else - page = list_entry(ballooned_pages.next, struct page, lru); + page = list_entry(ballooned_pages.next, struct page, lru); + if (require_lowmem && PageHighMem(page)) + return NULL; list_del(&page->lru); - if (PageHighMem(page)) { + if (PageHighMem(page)) balloon_stats.balloon_high--; - inc_totalhigh_pages(); - } else + else balloon_stats.balloon_low--; - totalram_pages++; + adjust_managed_page_count(page, 1); return page; } -static struct page *balloon_first_page(void) -{ - if (list_empty(&ballooned_pages)) - return NULL; - return list_entry(ballooned_pages.next, struct page, lru); -} - static struct page *balloon_next_page(struct page *page) { struct list_head *next = page->lru.next; @@ -179,6 +217,12 @@ static enum bp_state update_schedule(enum bp_state state) { + if (state == BP_WAIT) + return BP_WAIT; + + if (state == BP_ECANCELED) + return BP_ECANCELED; + if (state == BP_DONE) { balloon_stats.schedule_delay = 1; balloon_stats.retry_count = 1; @@ -203,55 +247,123 @@ } #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG -static long current_credit(void) +static void release_memory_resource(struct resource *resource) { - return balloon_stats.target_pages - balloon_stats.current_pages - - balloon_stats.hotplug_pages; + if (!resource) + return; + + /* + * No need to reset region to identity mapped since we now + * know that no I/O can be in this region + */ + release_resource(resource); + kfree(resource); } -static bool balloon_is_inflated(void) +static struct resource *additional_memory_resource(phys_addr_t size) { - if (balloon_stats.balloon_low || balloon_stats.balloon_high || - balloon_stats.balloon_hotplug) - return true; - else - return false; -} + struct resource *res; + int ret; -/* - * reserve_additional_memory() adds memory region of size >= credit above - * max_pfn. New region is section aligned and size is modified to be multiple - * of section size. Those features allow optimal use of address space and - * establish proper alignment when this function is called first time after - * boot (last section not fully populated at boot time contains unused memory - * pages with PG_reserved bit not set; online_pages_range() does not allow page - * onlining in whole range if first onlined page does not have PG_reserved - * bit set). Real size of added memory is established at page onlining stage. - */ + res = kzalloc(sizeof(*res), GFP_KERNEL); + if (!res) + return NULL; + + res->name = "System RAM"; + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; + + ret = allocate_resource(&iomem_resource, res, + size, 0, -1, + PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); + if (ret < 0) { + pr_err("Cannot allocate new System RAM resource\n"); + kfree(res); + return NULL; + } + +#ifdef CONFIG_SPARSEMEM + { + unsigned long limit = 1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT); + unsigned long pfn = res->start >> PAGE_SHIFT; + + if (pfn > limit) { + pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n", + pfn, limit); + release_memory_resource(res); + return NULL; + } + } +#endif + + return res; +} -static enum bp_state reserve_additional_memory(long credit) +static enum bp_state reserve_additional_memory(void) { + long credit; + struct resource *resource; int nid, rc; - u64 hotplug_start_paddr; - unsigned long balloon_hotplug = credit; + unsigned long balloon_hotplug; - hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); - balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); - nid = memory_add_physaddr_to_nid(hotplug_start_paddr); + credit = balloon_stats.target_pages + balloon_stats.target_unpopulated + - balloon_stats.total_pages; - rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); + /* + * Already hotplugged enough pages? Wait for them to be + * onlined. + */ + if (credit <= 0) + return BP_WAIT; - if (rc) { - pr_info("xen_balloon: %s: add_memory() failed: %i\n", __func__, rc); - return BP_EAGAIN; + balloon_hotplug = round_up(credit, PAGES_PER_SECTION); + + resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE); + if (!resource) + goto err; + + nid = memory_add_physaddr_to_nid(resource->start); + +#ifdef CONFIG_XEN_HAVE_PVMMU + /* + * We don't support PV MMU when Linux and Xen is using + * different page granularity. + */ + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); + + /* + * add_memory() will build page tables for the new memory so + * the p2m must contain invalid entries so the correct + * non-present PTEs will be written. + * + * If a failure occurs, the original (identity) p2m entries + * are not restored since this region is now known not to + * conflict with any devices. + */ + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long pfn, i; + + pfn = PFN_DOWN(resource->start); + for (i = 0; i < balloon_hotplug; i++) { + if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { + pr_warn("set_phys_to_machine() failed, no memory added\n"); + goto err; + } + } } +#endif - balloon_hotplug -= credit; + rc = add_memory_resource(nid, resource); + if (rc) { + pr_warn("Cannot add additional memory (%i)\n", rc); + goto err; + } - balloon_stats.hotplug_pages += credit; - balloon_stats.balloon_hotplug = balloon_hotplug; + balloon_stats.total_pages += balloon_hotplug; - return BP_DONE; + return BP_WAIT; + err: + release_memory_resource(resource); + return BP_ECANCELED; } static void xen_online_page(struct page *page) @@ -262,11 +374,6 @@ __balloon_append(page); - if (balloon_stats.hotplug_pages) - --balloon_stats.hotplug_pages; - else - --balloon_stats.balloon_hotplug; - mutex_unlock(&balloon_mutex); } @@ -283,63 +390,48 @@ .priority = 0 }; #else -static long current_credit(void) +static enum bp_state reserve_additional_memory(void) { - unsigned long target = balloon_stats.target_pages; - - target = min(target, - balloon_stats.current_pages + - balloon_stats.balloon_low + - balloon_stats.balloon_high); - - return target - balloon_stats.current_pages; + balloon_stats.target_pages = balloon_stats.current_pages; + return BP_ECANCELED; } +#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ -static bool balloon_is_inflated(void) +static long current_credit(void) { - if (balloon_stats.balloon_low || balloon_stats.balloon_high) - return true; - else - return false; + return balloon_stats.target_pages - balloon_stats.current_pages; } -static enum bp_state reserve_additional_memory(long credit) +static bool balloon_is_inflated(void) { - balloon_stats.target_pages = balloon_stats.current_pages; - return BP_DONE; + return balloon_stats.balloon_low || balloon_stats.balloon_high; } -#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ static enum bp_state increase_reservation(unsigned long nr_pages) { int rc; - unsigned long pfn, i; + unsigned long i; struct page *page; struct xen_memory_reservation reservation = { .address_bits = 0, - .extent_order = 0, + .extent_order = EXTENT_ORDER, .domid = DOMID_SELF }; -#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG - if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) { - nr_pages = min(nr_pages, balloon_stats.balloon_hotplug); - balloon_stats.hotplug_pages += nr_pages; - balloon_stats.balloon_hotplug -= nr_pages; - return BP_DONE; - } -#endif - if (nr_pages > ARRAY_SIZE(frame_list)) nr_pages = ARRAY_SIZE(frame_list); - page = balloon_first_page(); + page = list_first_entry_or_null(&ballooned_pages, struct page, lru); for (i = 0; i < nr_pages; i++) { if (!page) { nr_pages = i; break; } - frame_list[i] = page_to_pfn(page); + + /* XENMEM_populate_physmap requires a PFN based on Xen + * granularity. + */ + frame_list[i] = page_to_xen_pfn(page); page = balloon_next_page(page); } @@ -353,28 +445,32 @@ page = balloon_retrieve(false); BUG_ON(page == NULL); - pfn = page_to_pfn(page); - BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && - phys_to_machine_mapping_valid(pfn)); - - set_phys_to_machine(pfn, frame_list[i]); - #ifdef CONFIG_XEN_HAVE_PVMMU - /* Link back into the page tables if not highmem. */ - if (xen_pv_domain() && !PageHighMem(page)) { - int ret; - ret = HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - mfn_pte(frame_list[i], PAGE_KERNEL), - 0); - BUG_ON(ret); + /* + * We don't support PV MMU when Linux and Xen is using + * different page granularity. + */ + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); + + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long pfn = page_to_pfn(page); + + set_phys_to_machine(pfn, frame_list[i]); + + /* Link back into the page tables if not highmem. */ + if (!PageHighMem(page)) { + int ret; + ret = HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << PAGE_SHIFT), + mfn_pte(frame_list[i], PAGE_KERNEL), + 0); + BUG_ON(ret); + } } #endif /* Relinquish the page back to the allocator. */ - ClearPageReserved(page); - init_page_count(page); - __free_page(page); + __free_reserved_page(page); } balloon_stats.current_pages += rc; @@ -385,23 +481,15 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) { enum bp_state state = BP_DONE; - unsigned long pfn, i; - struct page *page; + unsigned long i; + struct page *page, *tmp; int ret; struct xen_memory_reservation reservation = { .address_bits = 0, - .extent_order = 0, + .extent_order = EXTENT_ORDER, .domid = DOMID_SELF }; - -#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG - if (balloon_stats.hotplug_pages) { - nr_pages = min(nr_pages, balloon_stats.hotplug_pages); - balloon_stats.hotplug_pages -= nr_pages; - balloon_stats.balloon_hotplug += nr_pages; - return BP_DONE; - } -#endif + LIST_HEAD(pages); if (nr_pages > ARRAY_SIZE(frame_list)) nr_pages = ARRAY_SIZE(frame_list); @@ -413,33 +501,54 @@ state = BP_EAGAIN; break; } + scrub_page(page); + list_add(&page->lru, &pages); + } - pfn = page_to_pfn(page); - frame_list[i] = pfn_to_mfn(pfn); + /* + * Ensure that ballooned highmem pages don't have kmaps. + * + * Do this before changing the p2m as kmap_flush_unused() + * reads PTEs to obtain pages (and hence needs the original + * p2m entry). + */ + kmap_flush_unused(); - scrub_page(page); + /* + * Setup the frame, update direct mapping, invalidate P2M, + * and add to balloon. + */ + i = 0; + list_for_each_entry_safe(page, tmp, &pages, lru) { + /* XENMEM_decrease_reservation requires a GFN */ + frame_list[i++] = xen_page_to_gfn(page); #ifdef CONFIG_XEN_HAVE_PVMMU - if (xen_pv_domain() && !PageHighMem(page)) { - ret = HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - __pte_ma(0), 0); - BUG_ON(ret); + /* + * We don't support PV MMU when Linux and Xen is using + * different page granularity. + */ + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); + + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long pfn = page_to_pfn(page); + + if (!PageHighMem(page)) { + ret = HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << PAGE_SHIFT), + __pte_ma(0), 0); + BUG_ON(ret); + } + __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); } #endif + list_del(&page->lru); + + balloon_append(page); } - /* Ensure that ballooned highmem pages don't have kmaps. */ - kmap_flush_unused(); flush_tlb_all(); - /* No more mappings: invalidate P2M and add to balloon. */ - for (i = 0; i < nr_pages; i++) { - pfn = mfn_to_pfn(frame_list[i]); - __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); - balloon_append(pfn_to_page(pfn)); - } - set_xen_guest_handle(reservation.extent_start, frame_list); reservation.nr_extents = nr_pages; ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); @@ -451,7 +560,7 @@ } /* - * We avoid multiple worker processes conflicting via the balloon mutex. + * As this is a work item it is guaranteed to run as a single instance only. * We may of course race updates of the target counts (which are protected * by the balloon lock), or with changes to the Xen hard limit, but we will * recover from these in time. @@ -461,16 +570,17 @@ enum bp_state state = BP_DONE; long credit; - mutex_lock(&balloon_mutex); do { + mutex_lock(&balloon_mutex); + credit = current_credit(); if (credit > 0) { if (balloon_is_inflated()) state = increase_reservation(credit); else - state = reserve_additional_memory(credit); + state = reserve_additional_memory(); } if (credit < 0) @@ -478,17 +588,15 @@ state = update_schedule(state); -#ifndef CONFIG_PREEMPT - if (need_resched()) - schedule(); -#endif + mutex_unlock(&balloon_mutex); + + cond_resched(); + } while (credit && state == BP_DONE); /* Schedule more work if there is some still to be done. */ if (state == BP_EAGAIN) schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); - - mutex_unlock(&balloon_mutex); } /* Resets the Xen limit, sets new target, and kicks off processing. */ @@ -500,41 +608,71 @@ } EXPORT_SYMBOL_GPL(balloon_set_new_target); +static int add_ballooned_pages(int nr_pages) +{ + enum bp_state st; + + if (xen_hotplug_unpopulated) { + st = reserve_additional_memory(); + if (st != BP_ECANCELED) { + mutex_unlock(&balloon_mutex); + wait_event(balloon_wq, + !list_empty(&ballooned_pages)); + mutex_lock(&balloon_mutex); + return 0; + } + } + + st = decrease_reservation(nr_pages, GFP_USER); + if (st != BP_DONE) + return -ENOMEM; + + return 0; +} + /** * alloc_xenballooned_pages - get pages that have been ballooned out * @nr_pages: Number of pages to get * @pages: pages returned - * @highmem: allow highmem pages * @return 0 on success, error otherwise */ -int alloc_xenballooned_pages(int nr_pages, struct page **pages, bool highmem) +int alloc_xenballooned_pages(int nr_pages, struct page **pages) { int pgno = 0; struct page *page; + int ret; + mutex_lock(&balloon_mutex); + + balloon_stats.target_unpopulated += nr_pages; + while (pgno < nr_pages) { - page = balloon_retrieve(highmem); - if (page && (highmem || !PageHighMem(page))) { + page = balloon_retrieve(true); + if (page) { pages[pgno++] = page; +#ifdef CONFIG_XEN_HAVE_PVMMU + /* + * We don't support PV MMU when Linux and Xen is using + * different page granularity. + */ + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); + + ret = xen_alloc_p2m_entry(page_to_pfn(page)); + if (ret < 0) + goto out_undo; +#endif } else { - enum bp_state st; - if (page) - balloon_append(page); - st = decrease_reservation(nr_pages - pgno, - highmem ? GFP_HIGHUSER : GFP_USER); - if (st != BP_DONE) + ret = add_ballooned_pages(nr_pages - pgno); + if (ret < 0) goto out_undo; } } mutex_unlock(&balloon_mutex); return 0; out_undo: - while (pgno) - balloon_append(pages[--pgno]); - /* Free the memory back to the kernel soon */ - schedule_delayed_work(&balloon_worker, 0); mutex_unlock(&balloon_mutex); - return -ENOMEM; + free_xenballooned_pages(pgno, pages); + return ret; } EXPORT_SYMBOL(alloc_xenballooned_pages); @@ -554,6 +692,8 @@ balloon_append(pages[i]); } + balloon_stats.target_unpopulated -= nr_pages; + /* The balloon may be too large now. Shrink it if needed. */ if (current_credit()) schedule_delayed_work(&balloon_worker, 0); @@ -582,6 +722,8 @@ don't subtract from it. */ __balloon_append(page); } + + balloon_stats.total_pages += extra_pfn_end - start_pfn; } static int __init balloon_init(void) @@ -591,14 +733,15 @@ if (!xen_domain()) return -ENODEV; - pr_info("xen/balloon: Initialising balloon driver.\n"); + pr_info("Initialising balloon driver\n"); balloon_stats.current_pages = xen_pv_domain() ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) - : max_pfn; + : get_num_physpages(); balloon_stats.target_pages = balloon_stats.current_pages; balloon_stats.balloon_low = 0; balloon_stats.balloon_high = 0; + balloon_stats.total_pages = balloon_stats.current_pages; balloon_stats.schedule_delay = 1; balloon_stats.max_schedule_delay = 32; @@ -606,11 +749,9 @@ balloon_stats.max_retry_count = RETRY_UNLIMITED; #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG - balloon_stats.hotplug_pages = 0; - balloon_stats.balloon_hotplug = 0; - set_online_page_callback(&xen_online_page); register_memory_notifier(&xen_memory_nb); + register_sysctl_table(xen_root); #endif /* @@ -618,9 +759,9 @@ * regions (see arch/x86/xen/setup.c). */ for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) - if (xen_extra_mem[i].size) - balloon_add_region(PFN_UP(xen_extra_mem[i].start), - PFN_DOWN(xen_extra_mem[i].size)); + if (xen_extra_mem[i].n_pfns) + balloon_add_region(xen_extra_mem[i].start_pfn, + xen_extra_mem[i].n_pfns); return 0; }