From bbc76be67c2c0c12548937a07ea3643c32a95b8c Mon Sep 17 00:00:00 2001 From: Wen Congyang Date: Fri, 22 Feb 2013 16:32:54 -0800 Subject: [PATCH] memory-hotplug: remove redundant codes offlining memory blocks and checking whether memory blocks are offlined are very similar. This patch introduces a new function to remove redundant codes. Signed-off-by: Wen Congyang Signed-off-by: Tang Chen Reviewed-by: Kamezawa Hiroyuki Cc: KOSAKI Motohiro Cc: Jiang Liu Cc: Jianguo Wu Cc: Lai Jiangshan Cc: Wu Jianguo Cc: Yasuaki Ishimatsu Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 129 ++++++++++++++++++++++++++++---------------- 1 file changed, 82 insertions(+), 47 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 5d350f5c68e..e5b91b12cec 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1380,20 +1380,26 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages) return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ); } -int remove_memory(u64 start, u64 size) +/** + * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn) + * @start_pfn: start pfn of the memory range + * @end_pfn: end pft of the memory range + * @arg: argument passed to func + * @func: callback for each memory section walked + * + * This function walks through all present mem sections in range + * [start_pfn, end_pfn) and call func on each mem section. + * + * Returns the return value of func. + */ +static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn, + void *arg, int (*func)(struct memory_block *, void *)) { struct memory_block *mem = NULL; struct mem_section *section; - unsigned long start_pfn, end_pfn; unsigned long pfn, section_nr; int ret; - int return_on_error = 0; - int retry = 0; - - start_pfn = PFN_DOWN(start); - end_pfn = start_pfn + PFN_DOWN(size); -repeat: for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { section_nr = pfn_to_section_nr(pfn); if (!present_section_nr(section_nr)) @@ -1410,22 +1416,76 @@ repeat: if (!mem) continue; - ret = offline_memory_block(mem); + ret = func(mem, arg); if (ret) { - if (return_on_error) { - kobject_put(&mem->dev.kobj); - return ret; - } else { - retry = 1; - } + kobject_put(&mem->dev.kobj); + return ret; } } if (mem) kobject_put(&mem->dev.kobj); - if (retry) { - return_on_error = 1; + return 0; +} + +/** + * offline_memory_block_cb - callback function for offlining memory block + * @mem: the memory block to be offlined + * @arg: buffer to hold error msg + * + * Always return 0, and put the error msg in arg if any. + */ +static int offline_memory_block_cb(struct memory_block *mem, void *arg) +{ + int *ret = arg; + int error = offline_memory_block(mem); + + if (error != 0 && *ret == 0) + *ret = error; + + return 0; +} + +static int is_memblock_offlined_cb(struct memory_block *mem, void *arg) +{ + int ret = !is_memblock_offlined(mem); + + if (unlikely(ret)) + pr_warn("removing memory fails, because memory " + "[%#010llx-%#010llx] is onlined\n", + PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)), + PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1); + + return ret; +} + +int remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn, end_pfn; + int ret = 0; + int retry = 1; + + start_pfn = PFN_DOWN(start); + end_pfn = start_pfn + PFN_DOWN(size); + + /* + * When CONFIG_MEMCG is on, one memory block may be used by other + * blocks to store page cgroup when onlining pages. But we don't know + * in what order pages are onlined. So we iterate twice to offline + * memory: + * 1st iterate: offline every non primary memory block. + * 2nd iterate: offline primary (i.e. first added) memory block. + */ +repeat: + walk_memory_range(start_pfn, end_pfn, &ret, + offline_memory_block_cb); + if (ret) { + if (!retry) + return ret; + + retry = 0; + ret = 0; goto repeat; } @@ -1443,38 +1503,13 @@ repeat: * memory blocks are offlined. */ - mem = NULL; - for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { - section_nr = pfn_to_section_nr(pfn); - if (!present_section_nr(section_nr)) - continue; - - section = __nr_to_section(section_nr); - /* same memblock? */ - if (mem) - if ((section_nr >= mem->start_section_nr) && - (section_nr <= mem->end_section_nr)) - continue; - - mem = find_memory_block_hinted(section, mem); - if (!mem) - continue; - - ret = is_memblock_offlined(mem); - if (!ret) { - pr_warn("removing memory fails, because memory " - "[%#010llx-%#010llx] is onlined\n", - PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)), - PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1); - - kobject_put(&mem->dev.kobj); - unlock_memory_hotplug(); - return ret; - } + ret = walk_memory_range(start_pfn, end_pfn, NULL, + is_memblock_offlined_cb); + if (ret) { + unlock_memory_hotplug(); + return ret; } - if (mem) - kobject_put(&mem->dev.kobj); unlock_memory_hotplug(); return 0; -- 2.20.1