* [Resend Patch 0/2] mm/memory_hotplug: fix hot remove bug
@ 2016-12-21 15:47 Yasuaki Ishimatsu
2016-12-21 15:49 ` [Resend PATCH 1/2] mm/sparse: use page_private() to get page->private value Yasuaki Ishimatsu
0 siblings, 1 reply; 5+ messages in thread
From: Yasuaki Ishimatsu @ 2016-12-21 15:47 UTC (permalink / raw)
To: linux-mm, linux-kernel, x86
Cc: akpm, tglx, mingo, hpa, dave.hansen, vbabka, mgorman, qiuxishi
Here are two patches for memory hotplug:
Yasuaki Ishimatsu (2):
mm/sparse: use page_private() to get page->private value
mm/memory_hotplug: set magic number to page->freelsit instead
of page->lru.next
arch/x86/mm/init_64.c | 2 +-
mm/memory_hotplug.c | 5 +++--
mm/sparse.c | 4 ++--
3 files changed, 6 insertions(+), 5 deletions(-)
^ permalink raw reply [flat|nested] 5+ messages in thread* [Resend PATCH 1/2] mm/sparse: use page_private() to get page->private value 2016-12-21 15:47 [Resend Patch 0/2] mm/memory_hotplug: fix hot remove bug Yasuaki Ishimatsu @ 2016-12-21 15:49 ` Yasuaki Ishimatsu 2016-12-21 15:49 ` [Resend PATCH 2/2] mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next Yasuaki Ishimatsu 0 siblings, 1 reply; 5+ messages in thread From: Yasuaki Ishimatsu @ 2016-12-21 15:49 UTC (permalink / raw) To: linux-mm, linux-kernel, x86 Cc: akpm, tglx, mingo, hpa, dave.hansen, vbabka, mgorman, qiuxishi free_map_bootmem() uses page->private directly to set removing_section_nr argument. But to get page->private value, page_private() has been prepared. So free_map_bootmem() should use page_private() instead of page->private. Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> --- mm/sparse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/sparse.c b/mm/sparse.c index 1e168bf..dc30a70 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -667,7 +667,7 @@ static void free_map_bootmem(struct page *memmap) BUG_ON(magic == NODE_INFO); maps_section_nr = pfn_to_section_nr(page_to_pfn(page)); - removing_section_nr = page->private; + removing_section_nr = page_private(page); /* * When this function is called, the removing section is -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [Resend PATCH 2/2] mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next 2016-12-21 15:49 ` [Resend PATCH 1/2] mm/sparse: use page_private() to get page->private value Yasuaki Ishimatsu @ 2016-12-21 15:49 ` Yasuaki Ishimatsu 2017-02-03 20:37 ` Yasuaki Ishimatsu 0 siblings, 1 reply; 5+ messages in thread From: Yasuaki Ishimatsu @ 2016-12-21 15:49 UTC (permalink / raw) To: linux-mm, linux-kernel, x86 Cc: akpm, tglx, mingo, hpa, dave.hansen, vbabka, mgorman, qiuxishi To identify that pages of page table are allocated from bootmem allocator, magic number sets to page->lru.next. But page->lru list is initialized in reserve_bootmem_region(). So when calling free_pagetable(), the function cannot find the magic number of pages. And free_pagetable() frees the pages by free_reserved_page() not put_page_bootmem(). But if the pages are allocated from bootmem allocator and used as page table, the pages have private flag. So before freeing the pages, we should clear the private flag by put_page_bootmem(). Before applying the commit 7bfec6f47bb0 ("mm, page_alloc: check multiple page fields with a single branch"), we could find the following visible issue: BUG: Bad page state in process kworker/u1024:1 page:ffffea103cfd8040 count:0 mapcount:0 mappi flags: 0x6fffff80000800(private) page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set bad because of flags: 0x800(private) <snip> Call Trace: [...] dump_stack+0x63/0x87 [...] bad_page+0x114/0x130 [...] free_pages_prepare+0x299/0x2d0 [...] free_hot_cold_page+0x31/0x150 [...] __free_pages+0x25/0x30 [...] free_pagetable+0x6f/0xb4 [...] remove_pagetable+0x379/0x7ff [...] vmemmap_free+0x10/0x20 [...] sparse_remove_one_section+0x149/0x180 [...] __remove_pages+0x2e9/0x4f0 [...] arch_remove_memory+0x63/0xc0 [...] remove_memory+0x8c/0xc0 [...] acpi_memory_device_remove+0x79/0xa5 [...] acpi_bus_trim+0x5a/0x8d [...] acpi_bus_trim+0x38/0x8d [...] acpi_device_hotplug+0x1b7/0x418 [...] acpi_hotplug_work_fn+0x1e/0x29 [...] process_one_work+0x152/0x400 [...] worker_thread+0x125/0x4b0 [...] ? __schedule+0x345/0x960 [...] ? rescuer_thread+0x380/0x380 [...] kthread+0xd8/0xf0 [...] ret_from_fork+0x22/0x40 [...] ? kthread_park+0x60/0x60 And the issue still silently occurs. Until freeing the pages of page table allocated from bootmem allocator, the page->freelist is never used. So the patch sets magic number to page->freelist instead of page->lru.next. Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> --- arch/x86/mm/init_64.c | 2 +- mm/memory_hotplug.c | 5 +++-- mm/sparse.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 963895f..b35e525 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -679,7 +679,7 @@ static void __meminit free_pagetable(struct page *page, int order) if (PageReserved(page)) { __ClearPageReserved(page); - magic = (unsigned long)page->lru.next; + magic = (unsigned long)page->freelist; if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) { while (nr_pages--) put_page_bootmem(page++); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index e43142c1..9847e4a 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -179,7 +179,7 @@ static void release_memory_resource(struct resource *res) void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) { - page->lru.next = (struct list_head *) type; + page->freelist = (void *) type; SetPagePrivate(page); set_page_private(page, info); page_ref_inc(page); @@ -189,11 +189,12 @@ void put_page_bootmem(struct page *page) { unsigned long type; - type = (unsigned long) page->lru.next; + type = (unsigned long) page->freelist; BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); if (page_ref_dec_return(page) == 1) { + page->freelist = NULL; ClearPagePrivate(page); set_page_private(page, 0); INIT_LIST_HEAD(&page->lru); diff --git a/mm/sparse.c b/mm/sparse.c index dc30a70..db6bf3c 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -662,7 +662,7 @@ static void free_map_bootmem(struct page *memmap) >> PAGE_SHIFT; for (i = 0; i < nr_pages; i++, page++) { - magic = (unsigned long) page->lru.next; + magic = (unsigned long) page->freelist; BUG_ON(magic == NODE_INFO); -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [Resend PATCH 2/2] mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next 2016-12-21 15:49 ` [Resend PATCH 2/2] mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next Yasuaki Ishimatsu @ 2017-02-03 20:37 ` Yasuaki Ishimatsu 2017-02-03 21:14 ` Yasuaki Ishimatsu 0 siblings, 1 reply; 5+ messages in thread From: Yasuaki Ishimatsu @ 2017-02-03 20:37 UTC (permalink / raw) To: akpm Cc: linux-mm, linux-kernel, x86, tglx, mingo, hpa, dave.hansen, vbabka, mgorman, qiuxishi Hi Andrew, Please apply the following patch into your tree because patch ("mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next") is not applied correctly. --- From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Date: Fri, 3 Feb 2017 15:18:03 -0500 Subject: [PATCH] Remove unnecessary code from get_page_bootmem() The following patch is not applied correctly. http://lkml.kernel.org/r/2c29bd9f-5b67-02d0-18a3-8828e78bbb6f@gmail.com So the following unnecessary code still remains. get_page_bootmem() { ... page->lru.next = (struct list_head *)type; ... The patch removeｓ this code from get_page_bootmem() Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> --- mm/memory_hotplug.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 19b460a..50b586c 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -179,7 +179,6 @@ static void release_memory_resource(struct resource *res) void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) { - page->lru.next = (struct list_head *)type; page->freelist = (void *)type; SetPagePrivate(page); set_page_private(page, info); -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [Resend PATCH 2/2] mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next 2017-02-03 20:37 ` Yasuaki Ishimatsu @ 2017-02-03 21:14 ` Yasuaki Ishimatsu 0 siblings, 0 replies; 5+ messages in thread From: Yasuaki Ishimatsu @ 2017-02-03 21:14 UTC (permalink / raw) To: akpm Cc: linux-mm, linux-kernel, x86, tglx, mingo, hpa, dave.hansen, vbabka, mgorman, qiuxishi TAB was replaced to white spaces. So please apply this one. --- From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Date: Fri, 3 Feb 2017 15:18:03 -0500 Subject: [PATCH] mm/memory_hotplug: Remove unnecessary code from get_page_bootmem() The following patch is not applied correctly. http://lkml.kernel.org/r/2c29bd9f-5b67-02d0-18a3-8828e78bbb6f@gmail.com So the following unnecessary code still remains. void get_page_bootmem() { ... page->lru.next = (struct list_head *)type; ... The patch removes this code from get_page_bootmem() --- mm/memory_hotplug.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 7409f25..d67787d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -179,7 +179,6 @@ static void release_memory_resource(struct resource *res) void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) { - page->lru.next = (struct list_head *)type; page->freelist = (void *)type; SetPagePrivate(page); set_page_private(page, info); -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-02-03 21:14 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2016-12-21 15:47 [Resend Patch 0/2] mm/memory_hotplug: fix hot remove bug Yasuaki Ishimatsu 2016-12-21 15:49 ` [Resend PATCH 1/2] mm/sparse: use page_private() to get page->private value Yasuaki Ishimatsu 2016-12-21 15:49 ` [Resend PATCH 2/2] mm/memory_hotplug: set magic number to page->freelsit instead of page->lru.next Yasuaki Ishimatsu 2017-02-03 20:37 ` Yasuaki Ishimatsu 2017-02-03 21:14 ` Yasuaki Ishimatsu
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