[PATCH] memory hotplug locking: node_size_lock
pgdat->node_size_lock is basically only neeeded in one place in the normal
code: show_mem(), which is the arch-specific sysrq-m printing function.
Strictly speaking, the architectures not doing memory hotplug do no need this
locking in show_mem(). However, they are all included for completeness. This
should also make any future consolidation of all of the implementations a
little more straightforward.
This lock is also held in the sparsemem code during a memory removal, as
sections are invalidated. This is the place there pfn_valid() is made false
for a memory area that's being removed. The lock is only required when doing
pfn_valid() operations on memory which the user does not already have a
reference on the page, such as in show_mem().
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/alpha/mm/numa.c b/arch/alpha/mm/numa.c
index c7481d5..6d52512 100644
--- a/arch/alpha/mm/numa.c
+++ b/arch/alpha/mm/numa.c
@@ -371,6 +371,8 @@
show_free_areas();
printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
for_each_online_node(nid) {
+ unsigned long flags;
+ pgdat_resize_lock(NODE_DATA(nid), &flags);
i = node_spanned_pages(nid);
while (i-- > 0) {
struct page *page = nid_page_nr(nid, i);
@@ -384,6 +386,7 @@
else
shared += page_count(page) - 1;
}
+ pgdat_resize_unlock(NODE_DATA(nid), &flags);
}
printk("%ld pages of RAM\n",total);
printk("%ld free pages\n",free);
diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c
index 39c099f..9db3242 100644
--- a/arch/i386/mm/pgtable.c
+++ b/arch/i386/mm/pgtable.c
@@ -31,11 +31,13 @@
pg_data_t *pgdat;
unsigned long i;
struct page_state ps;
+ unsigned long flags;
printk(KERN_INFO "Mem-info:\n");
show_free_areas();
printk(KERN_INFO "Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
for_each_pgdat(pgdat) {
+ pgdat_resize_lock(pgdat, &flags);
for (i = 0; i < pgdat->node_spanned_pages; ++i) {
page = pgdat_page_nr(pgdat, i);
total++;
@@ -48,6 +50,7 @@
else if (page_count(page))
shared += page_count(page) - 1;
}
+ pgdat_resize_unlock(pgdat, &flags);
}
printk(KERN_INFO "%d pages of RAM\n", total);
printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index a3788fb..a88cdb7 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -555,9 +555,13 @@
show_free_areas();
printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
for_each_pgdat(pgdat) {
- unsigned long present = pgdat->node_present_pages;
+ unsigned long present;
+ unsigned long flags;
int shared = 0, cached = 0, reserved = 0;
+
printk("Node ID: %d\n", pgdat->node_id);
+ pgdat_resize_lock(pgdat, &flags);
+ present = pgdat->node_present_pages;
for(i = 0; i < pgdat->node_spanned_pages; i++) {
struct page *page;
if (pfn_valid(pgdat->node_start_pfn + i))
@@ -571,6 +575,7 @@
else if (page_count(page))
shared += page_count(page)-1;
}
+ pgdat_resize_unlock(pgdat, &flags);
total_present += present;
total_reserved += reserved;
total_cached += cached;
diff --git a/arch/m32r/mm/init.c b/arch/m32r/mm/init.c
index d9a40b1..6facf15 100644
--- a/arch/m32r/mm/init.c
+++ b/arch/m32r/mm/init.c
@@ -48,6 +48,8 @@
show_free_areas();
printk("Free swap: %6ldkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
for_each_pgdat(pgdat) {
+ unsigned long flags;
+ pgdat_resize_lock(pgdat, &flags);
for (i = 0; i < pgdat->node_spanned_pages; ++i) {
page = pgdat_page_nr(pgdat, i);
total++;
@@ -60,6 +62,7 @@
else if (page_count(page))
shared += page_count(page) - 1;
}
+ pgdat_resize_unlock(pgdat, &flags);
}
printk("%d pages of RAM\n", total);
printk("%d pages of HIGHMEM\n",highmem);
@@ -150,10 +153,14 @@
int reservedpages, nid, i;
reservedpages = 0;
- for_each_online_node(nid)
+ for_each_online_node(nid) {
+ unsigned long flags;
+ pgdat_resize_lock(NODE_DATA(nid), &flags);
for (i = 0 ; i < MAX_LOW_PFN(nid) - START_PFN(nid) ; i++)
if (PageReserved(nid_page_nr(nid, i)))
reservedpages++;
+ pgdat_resize_unlock(NODE_DATA(nid), &flags);
+ }
return reservedpages;
}
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 2886ad7..29b998e 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -505,7 +505,9 @@
for (j = node_start_pfn(i); j < node_end_pfn(i); j++) {
struct page *p;
+ unsigned long flags;
+ pgdat_resize_lock(NODE_DATA(i), &flags);
p = nid_page_nr(i, j) - node_start_pfn(i);
total++;
@@ -517,6 +519,7 @@
free++;
else
shared += page_count(p) - 1;
+ pgdat_resize_unlock(NODE_DATA(i), &flags);
}
}
#endif
diff --git a/arch/ppc64/mm/init.c b/arch/ppc64/mm/init.c
index a45584b..975b26d 100644
--- a/arch/ppc64/mm/init.c
+++ b/arch/ppc64/mm/init.c
@@ -104,6 +104,8 @@
show_free_areas();
printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
for_each_pgdat(pgdat) {
+ unsigned long flags;
+ pgdat_resize_lock(pgdat, &flags);
for (i = 0; i < pgdat->node_spanned_pages; i++) {
page = pgdat_page_nr(pgdat, i);
total++;
@@ -114,6 +116,7 @@
else if (page_count(page))
shared += page_count(page) - 1;
}
+ pgdat_resize_unlock(pgdat, &flags);
}
printk("%ld pages of RAM\n", total);
printk("%ld reserved pages\n", reserved);
@@ -647,11 +650,14 @@
#endif
for_each_pgdat(pgdat) {
+ unsigned long flags;
+ pgdat_resize_lock(pgdat, &flags);
for (i = 0; i < pgdat->node_spanned_pages; i++) {
page = pgdat_page_nr(pgdat, i);
if (PageReserved(page))
reservedpages++;
}
+ pgdat_resize_unlock(pgdat, &flags);
}
codesize = (unsigned long)&_etext - (unsigned long)&_stext;