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Message-Id: <1357723959-5416-4-git-send-email-tangchen@cn.fujitsu.com>
Date: Wed, 9 Jan 2013 17:32:27 +0800
From: Tang Chen <tangchen@...fujitsu.com>
To: akpm@...ux-foundation.org, rientjes@...gle.com,
len.brown@...el.com, benh@...nel.crashing.org, paulus@...ba.org,
cl@...ux.com, minchan.kim@...il.com,
kosaki.motohiro@...fujitsu.com, isimatu.yasuaki@...fujitsu.com,
wujianguo@...wei.com, wency@...fujitsu.com,
tangchen@...fujitsu.com, hpa@...or.com, linfeng@...fujitsu.com,
laijs@...fujitsu.com, mgorman@...e.de, yinghai@...nel.org,
glommer@...allels.com
Cc: x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-acpi@...r.kernel.org,
linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
linux-ia64@...r.kernel.org, cmetcalf@...era.com,
sparclinux@...r.kernel.org
Subject: [PATCH v6 03/15] memory-hotplug: remove redundant codes
From: Wen Congyang <wency@...fujitsu.com>
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 <wency@...fujitsu.com>
Signed-off-by: Tang Chen <tangchen@...fujitsu.com>
Reviewed-by: Kamezawa Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
---
mm/memory_hotplug.c | 129 ++++++++++++++++++++++++++++++++------------------
1 files changed, 82 insertions(+), 47 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 5808045..69d62eb 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1381,20 +1381,26 @@ 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))
@@ -1411,22 +1417,76 @@ 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;
}
@@ -1444,38 +1504,13 @@ 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;
--
1.7.1
--
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