From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZoXVk6cDRZ8OcYZFIHR2mCVOX0yJ5uWDDDDdlKsS8PeMUQK0fpQjZ3eR40OKjQASScQ8UcD ARC-Seal: i=1; a=rsa-sha256; t=1525081379; cv=none; d=google.com; s=arc-20160816; b=pZAg6ryCRJSjYemfADijODxx1pvAYIogD10HUGBgppKEVyzPMmWEIaJAUF3ffk4yyD E0mU7A2IjzWiLx8V1/TYxifUe4poAGyuhD1BSP7NYah3cFQX1wzjRXNz+ec9Xqq1ZL9H Lv9NTlmFuKwSX8dqKPyItScL/M7u5HGP6ebTq7MjN0T1dYWDVUHujIWeIIJAM/S+4o1d 2iQiJZ9bdfuPaeIPF8g1YxpJGl6rxYEoCLvxMpZ64vm/LkJjN6nZxwfRGixQTcnLVNQS 84YYAfrx0WHpsNFa4qmioJ/eoDNWC+eEhmZp2e2DOMtockl+TShdNTjXWboh94k/bpIq 60hw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :arc-authentication-results; bh=Y8fMAfSHritLnWkT0WvH7RFx/qlMA9hp8NNej6VUNds=; b=MiKvdssoCwyq1QoTNVZoyEEES1l3j+O4zuzeRK3B8Pfu/clMeC6znV5xtgMdzY+3hs m90PzgODiuuUHjWtjHQvDqhI/H6joVhsOza0JSXzk+IVz63fAt1fIQNr0sqSggRTLORb f+Kgig+AAmgzt7GrZbZ1zqVSPBqQDGRbm0DSL6497nlbJe2LWOMKaKv702uyk+yYk6Pb K3kFSLP233J0oExSs/4JFF4oY4lDodCMC475wkjW/xXzxyy/k08lakU2ugAl7dXRK8id NNRw7IdseLT1APRpaPiGHd9cpNcDAYJNjJZS4CWO8QxUxgAmD4jbiWHCq4t1qQGD1y1F nohg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com From: David Hildenbrand To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, David Hildenbrand , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Greg Kroah-Hartman , Rashmica Gupta , Balbir Singh , Andrew Morton , Michal Hocko , Vlastimil Babka , Dan Williams , Joonsoo Kim , Pavel Tatashin , Reza Arbab , Thomas Gleixner Subject: [PATCH RCFv2 6/7] mm/memory_hotplug: teach offline_pages() to not try forever Date: Mon, 30 Apr 2018 11:42:35 +0200 Message-Id: <20180430094236.29056-7-david@redhat.com> In-Reply-To: <20180430094236.29056-1-david@redhat.com> References: <20180430094236.29056-1-david@redhat.com> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1599163732436361107?= X-GMAIL-MSGID: =?utf-8?q?1599163732436361107?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: It can easily happen that we get stuck forever trying to offline pages - e.g. on persistent errors. Let's add a way to change this behavior and fail fast. This is interesting if offline_pages() is called from a driver and we just want to find some block to offline. Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Greg Kroah-Hartman Cc: Rashmica Gupta Cc: Balbir Singh Cc: Andrew Morton Cc: Michal Hocko Cc: Vlastimil Babka Cc: Dan Williams Cc: Joonsoo Kim Cc: Pavel Tatashin Cc: Reza Arbab Cc: Thomas Gleixner Signed-off-by: David Hildenbrand --- arch/powerpc/platforms/powernv/memtrace.c | 2 +- drivers/base/memory.c | 2 +- include/linux/memory_hotplug.h | 8 ++++---- mm/memory_hotplug.c | 14 ++++++++++---- 4 files changed, 16 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c index fc222a0c2ac4..8ce71f7e1558 100644 --- a/arch/powerpc/platforms/powernv/memtrace.c +++ b/arch/powerpc/platforms/powernv/memtrace.c @@ -110,7 +110,7 @@ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages) walk_memory_range(start_pfn, end_pfn, (void *)MEM_GOING_OFFLINE, change_memblock_state); - if (offline_pages(start_pfn, nr_pages)) { + if (offline_pages(start_pfn, nr_pages, true)) { walk_memory_range(start_pfn, end_pfn, (void *)MEM_ONLINE, change_memblock_state); return false; diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 3b8616551561..c785e4c01b23 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -248,7 +248,7 @@ memory_block_action(struct memory_block *mem, unsigned long action) ret = online_pages(start_pfn, nr_pages, mem->online_type); break; case MEM_OFFLINE: - ret = offline_pages(start_pfn, nr_pages); + ret = offline_pages(start_pfn, nr_pages, true); break; default: WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: " diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 497e28f5b000..ae53017b54df 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -303,7 +303,8 @@ static inline void pgdat_resize_init(struct pglist_data *pgdat) {} extern bool is_mem_section_removable(unsigned long pfn, unsigned long nr_pages); extern void try_offline_node(int nid); -extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages); +extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages, + bool retry_forever); extern void remove_memory(int nid, u64 start, u64 size); #else @@ -315,7 +316,8 @@ static inline bool is_mem_section_removable(unsigned long pfn, static inline void try_offline_node(int nid) {} -static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages) +static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages, + bool retry_forever) { return -EINVAL; } @@ -333,9 +335,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, bool want_memblock); extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, unsigned long nr_pages, struct vmem_altmap *altmap); -extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages); extern bool is_memblock_offlined(struct memory_block *mem); -extern void remove_memory(int nid, u64 start, u64 size); extern int sparse_add_one_section(struct pglist_data *pgdat, unsigned long start_pfn, struct vmem_altmap *altmap); extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms, diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index d8f127754c2e..c47cc68341fc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1618,8 +1618,8 @@ static void node_states_clear_node(int node, struct memory_notify *arg) node_clear_state(node, N_MEMORY); } -static int __ref __offline_pages(unsigned long start_pfn, - unsigned long end_pfn) +static int __ref __offline_pages(unsigned long start_pfn, unsigned long end_pfn, + bool retry_forever) { unsigned long pfn, nr_pages; long offlined_pages; @@ -1671,6 +1671,10 @@ static int __ref __offline_pages(unsigned long start_pfn, pfn = scan_movable_pages(start_pfn, end_pfn); if (pfn) { /* We have movable pages */ ret = do_migrate_range(pfn, end_pfn); + if (ret && !retry_forever) { + ret = -EBUSY; + goto failed_removal; + } goto repeat; } @@ -1737,6 +1741,7 @@ static int __ref __offline_pages(unsigned long start_pfn, * offline_pages - offline pages in a given range (that are currently online) * @start_pfn: start pfn of the memory range * @nr_pages: the number of pages + * @retry_forever: weather to retry (possibly) forever * * This function tries to offline the given pages. The alignment/size that * can be used is given by offline_nr_pages. @@ -1749,9 +1754,10 @@ static int __ref __offline_pages(unsigned long start_pfn, * * Must be protected by mem_hotplug_begin() or a device_lock */ -int offline_pages(unsigned long start_pfn, unsigned long nr_pages) +int offline_pages(unsigned long start_pfn, unsigned long nr_pages, + bool retry_forever) { - return __offline_pages(start_pfn, start_pfn + nr_pages); + return __offline_pages(start_pfn, start_pfn + nr_pages, retry_forever); } #endif /* CONFIG_MEMORY_HOTREMOVE */ -- 2.14.3