From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by kanga.kvack.org (Postfix) with ESMTP id A78DA8E0038 for ; Wed, 9 Jan 2019 06:13:23 -0500 (EST) Received: by mail-pl1-f200.google.com with SMTP id g12so3967919pll.22 for ; Wed, 09 Jan 2019 03:13:23 -0800 (PST) Received: from alexa-out-blr.qualcomm.com (alexa-out-blr-02.qualcomm.com. [103.229.18.198]) by mx.google.com with ESMTPS id t12si64779560plr.311.2019.01.09.03.13.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Jan 2019 03:13:22 -0800 (PST) From: Arun KS Subject: [PATCH v8] mm/page_alloc.c: memory_hotplug: free pages as higher order Date: Wed, 9 Jan 2019 16:43:15 +0530 Message-Id: <1547032395-24582-1-git-send-email-arunks@codeaurora.org> Sender: owner-linux-mm@kvack.org List-ID: To: arunks.linux@gmail.com, alexander.h.duyck@linux.intel.com, akpm@linux-foundation.org, mhocko@kernel.org, vbabka@suse.cz, osalvador@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: getarunks@gmail.com, Arun KS When freeing pages are done with higher order, time spent on coalescing pages by buddy allocator can be reduced. With section size of 256MB, hot add latency of a single section shows improvement from 50-60 ms to less than 1 ms, hence improving the hot add latency by 60 times. Modify external providers of online callback to align with the change. Signed-off-by: Arun KS Acked-by: Michal Hocko Reviewed-by: Oscar Salvador --- Changes since v7: - Rebased to 5.0-rc1. - Fixed onlined_pages accounting. - Added comment for return value of online_page_callback. - Renamed xen_bring_pgs_online to xen_online_pages. Changes since v6: - Rebased to 4.20 - Changelog updated. - No improvement seen on arm64, hence removed removal of prefetch. Changes since v5: - Rebased to 4.20-rc1. - Changelog updated. Changes since v4: - As suggested by Michal Hocko, - Simplify logic in online_pages_block() by using get_order(). - Seperate out removal of prefetch from __free_pages_core(). Changes since v3: - Renamed _free_pages_boot_core -> __free_pages_core. - Removed prefetch from __free_pages_core. - Removed xen_online_page(). Changes since v2: - Reuse code from __free_pages_boot_core(). Changes since v1: - Removed prefetch(). Changes since RFC: - Rebase. - As suggested by Michal Hocko remove pages_per_block. - Modifed external providers of online_page_callback. v7: https://lore.kernel.org/patchwork/patch/1028908/ v6: https://lore.kernel.org/patchwork/patch/1007253/ v5: https://lore.kernel.org/patchwork/patch/995739/ v4: https://lore.kernel.org/patchwork/patch/995111/ v3: https://lore.kernel.org/patchwork/patch/992348/ v2: https://lore.kernel.org/patchwork/patch/991363/ v1: https://lore.kernel.org/patchwork/patch/989445/ RFC: https://lore.kernel.org/patchwork/patch/984754/ --- drivers/hv/hv_balloon.c | 6 +++-- drivers/xen/balloon.c | 21 +++++++++++------ include/linux/memory_hotplug.h | 2 +- mm/internal.h | 1 + mm/memory_hotplug.c | 51 +++++++++++++++++++++++++++++++----------- mm/page_alloc.c | 8 +++---- 6 files changed, 62 insertions(+), 27 deletions(-) diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index 5301fef..211f3fe 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -771,7 +771,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size, } } -static void hv_online_page(struct page *pg) +static int hv_online_page(struct page *pg, unsigned int order) { struct hv_hotadd_state *has; unsigned long flags; @@ -783,10 +783,12 @@ static void hv_online_page(struct page *pg) if ((pfn < has->start_pfn) || (pfn >= has->end_pfn)) continue; - hv_page_online_one(has, pg); + hv_bring_pgs_online(has, pfn, (1UL << order)); break; } spin_unlock_irqrestore(&dm_device.ha_lock, flags); + + return 0; } static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index ceb5048..116a042 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -345,7 +345,7 @@ static enum bp_state reserve_additional_memory(void) /* * add_memory_resource() will call online_pages() which in its turn - * will call xen_online_page() callback causing deadlock if we don't + * will call xen_online_pages() callback causing deadlock if we don't * release balloon_mutex here. Unlocking here is safe because the * callers drop the mutex before trying again. */ @@ -369,15 +369,22 @@ static enum bp_state reserve_additional_memory(void) return BP_ECANCELED; } -static void xen_online_page(struct page *page) +static int xen_online_pages(struct page *pg, unsigned int order) { - __online_page_set_limits(page); + unsigned long i, size = (1 << order); + unsigned long start_pfn = page_to_pfn(pg); + struct page *p; + pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn); mutex_lock(&balloon_mutex); - - __balloon_append(page); - + for (i = 0; i < size; i++) { + p = pfn_to_page(start_pfn + i); + __online_page_set_limits(p); + __balloon_append(p); + } mutex_unlock(&balloon_mutex); + + return 0; } static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) @@ -702,7 +709,7 @@ static int __init balloon_init(void) balloon_stats.max_retry_count = RETRY_UNLIMITED; #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG - set_online_page_callback(&xen_online_page); + set_online_page_callback(&xen_online_pages); register_memory_notifier(&xen_memory_nb); register_sysctl_table(xen_root); #endif diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 07da5c6..d56bfba 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -87,7 +87,7 @@ extern int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, unsigned long *valid_start, unsigned long *valid_end); extern void __offline_isolated_pages(unsigned long, unsigned long); -typedef void (*online_page_callback_t)(struct page *page); +typedef int (*online_page_callback_t)(struct page *page, unsigned int order); extern int set_online_page_callback(online_page_callback_t callback); extern int restore_online_page_callback(online_page_callback_t callback); diff --git a/mm/internal.h b/mm/internal.h index f4a7bb0..536bc2a 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -163,6 +163,7 @@ static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn, extern int __isolate_free_page(struct page *page, unsigned int order); extern void memblock_free_pages(struct page *page, unsigned long pfn, unsigned int order); +extern void __free_pages_core(struct page *page, unsigned int order); extern void prep_compound_page(struct page *page, unsigned int order); extern void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b9a667d..573d9c32 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -47,7 +47,7 @@ * and restore_online_page_callback() for generic callback restore. */ -static void generic_online_page(struct page *page); +static int generic_online_page(struct page *page, unsigned int order); static online_page_callback_t online_page_callback = generic_online_page; static DEFINE_MUTEX(online_page_callback_lock); @@ -656,30 +656,55 @@ void __online_page_free(struct page *page) } EXPORT_SYMBOL_GPL(__online_page_free); -static void generic_online_page(struct page *page) +static int generic_online_page(struct page *page, unsigned int order) { - __online_page_set_limits(page); - __online_page_increment_counters(page); - __online_page_free(page); + __free_pages_core(page, order); + totalram_pages_add(1UL << order); +#ifdef CONFIG_HIGHMEM + if (PageHighMem(page)) + totalhigh_pages_add(1UL << order); +#endif + return 0; +} + +static int online_pages_blocks(unsigned long start, unsigned long nr_pages) +{ + unsigned long end = start + nr_pages; + int order, ret, onlined_pages = 0; + + while (start < end) { + order = min(MAX_ORDER - 1, + get_order(PFN_PHYS(end) - PFN_PHYS(start))); + + /* + * External callback providers can deny onlining pages. So check + * for return value. + * zero : if all pages are onlined. + * positive : if only few pages are onlined. + * negative : if none of the pages are onlined. + */ + ret = (*online_page_callback)(pfn_to_page(start), order); + if (!ret) + onlined_pages += (1UL << order); + else if (ret > 0) + onlined_pages += ret; + + start += (1UL << order); + } + return onlined_pages; } static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { - unsigned long i; unsigned long onlined_pages = *(unsigned long *)arg; - struct page *page; if (PageReserved(pfn_to_page(start_pfn))) - for (i = 0; i < nr_pages; i++) { - page = pfn_to_page(start_pfn + i); - (*online_page_callback)(page); - onlined_pages++; - } + onlined_pages = online_pages_blocks(start_pfn, nr_pages); online_mem_sections(start_pfn, start_pfn + nr_pages); - *(unsigned long *)arg = onlined_pages; + *(unsigned long *)arg += onlined_pages; return 0; } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d295c9b..883212a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1303,7 +1303,7 @@ static void __free_pages_ok(struct page *page, unsigned int order) local_irq_restore(flags); } -static void __init __free_pages_boot_core(struct page *page, unsigned int order) +void __free_pages_core(struct page *page, unsigned int order) { unsigned int nr_pages = 1 << order; struct page *p = page; @@ -1382,7 +1382,7 @@ void __init memblock_free_pages(struct page *page, unsigned long pfn, { if (early_page_uninitialised(pfn)) return; - return __free_pages_boot_core(page, order); + __free_pages_core(page, order); } /* @@ -1472,14 +1472,14 @@ static void __init deferred_free_range(unsigned long pfn, if (nr_pages == pageblock_nr_pages && (pfn & (pageblock_nr_pages - 1)) == 0) { set_pageblock_migratetype(page, MIGRATE_MOVABLE); - __free_pages_boot_core(page, pageblock_order); + __free_pages_core(page, pageblock_order); return; } for (i = 0; i < nr_pages; i++, page++, pfn++) { if ((pfn & (pageblock_nr_pages - 1)) == 0) set_pageblock_migratetype(page, MIGRATE_MOVABLE); - __free_pages_boot_core(page, 0); + __free_pages_core(page, 0); } } -- 1.9.1