mm, meminit: replace rwsem with completion

[karo-tx-linux.git] / mm / page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ea0e6a6e7a11f69365082ae271c79ca3009c7943..322628278ae4081e3ee9cb2521f8c5392c584bda 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -18,7 +18,6 @@
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/interrupt.h>
-#include <linux/rwsem.h>
 #include <linux/pagemap.h>
 #include <linux/jiffies.h>
 #include <linux/bootmem.h>
@@ -1060,7 +1059,15 @@ static void __init deferred_free_range(struct page *page,
                __free_pages_boot_core(page, pfn, 0);
 }
 
-static __initdata DECLARE_RWSEM(pgdat_init_rwsem);
+/* Completion tracking for deferred_init_memmap() threads */
+static atomic_t pgdat_init_n_undone __initdata;
+static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
+
+static inline void __init pgdat_init_report_one_done(void)
+{
+       if (atomic_dec_and_test(&pgdat_init_n_undone))
+               complete(&pgdat_init_all_done_comp);
+}
 
 /* Initialise remaining memory on a node */
 static int __init deferred_init_memmap(void *data)
@@ -1077,7 +1084,7 @@ static int __init deferred_init_memmap(void *data)
        const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
 
        if (first_init_pfn == ULONG_MAX) {
-               up_read(&pgdat_init_rwsem);
+               pgdat_init_report_one_done();
                return 0;
        }
 
@@ -1177,7 +1184,8 @@ free_range:
 
        pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages,
                                        jiffies_to_msecs(jiffies - start));
-       up_read(&pgdat_init_rwsem);
+
+       pgdat_init_report_one_done();
        return 0;
 }
 
@@ -1185,14 +1193,14 @@ void __init page_alloc_init_late(void)
 {
        int nid;
 
+       /* There will be num_node_state(N_MEMORY) threads */
+       atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
        for_each_node_state(nid, N_MEMORY) {
-               down_read(&pgdat_init_rwsem);
                kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
        }
 
        /* Block until all are initialised */
-       down_write(&pgdat_init_rwsem);
-       up_write(&pgdat_init_rwsem);
+       wait_for_completion(&pgdat_init_all_done_comp);
 }
 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */