On Thu, 7 May 2015 08:25:18 +0100 Mel Gorman <[email protected]> wrote:
> Waiman Long reported that 24TB machines hit OOM during basic setup when > struct page initialisation was deferred. One approach is to initialise memory > on demand but it interferes with page allocator paths. This patch creates > dedicated threads to initialise memory before basic setup. It then blocks > on a rw_semaphore until completion as a wait_queue and counter is overkill. > This may be slower to boot but it's simplier overall and also gets rid of a > section mangling which existed so kswapd could do the initialisation. Seems a reasonable compromise. It makes a bit of a mess of the patch sequencing. Have some tweaklets: From: Andrew Morton <[email protected]> Subject: mm-meminit-finish-initialisation-of-struct-pages-before-basic-setup-fix include rwsem.h, use DECLARE_RWSEM, fix comment, remove unneeded cast Cc: Daniel J Blueman <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Nathan Zimmer <[email protected]> Cc: Scott Norton <[email protected]> Cc: Waiman Long <[email protected] Signed-off-by: Andrew Morton <[email protected]> --- mm/page_alloc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff -puN mm/page_alloc.c~mm-meminit-finish-initialisation-of-struct-pages-before-basic-setup-fix mm/page_alloc.c --- a/mm/page_alloc.c~mm-meminit-finish-initialisation-of-struct-pages-before-basic-setup-fix +++ a/mm/page_alloc.c @@ -18,6 +18,7 @@ #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> @@ -1075,12 +1076,12 @@ static void __init deferred_free_range(s __free_pages_boot_core(page, pfn, 0); } -static struct rw_semaphore __initdata pgdat_init_rwsem; +static __initdata DECLARE_RWSEM(pgdat_init_rwsem); /* Initialise remaining memory on a node */ static int __init deferred_init_memmap(void *data) { - pg_data_t *pgdat = (pg_data_t *)data; + pg_data_t *pgdat = data; int nid = pgdat->node_id; struct mminit_pfnnid_cache nid_init_state = { }; unsigned long start = jiffies; @@ -1096,7 +1097,7 @@ static int __init deferred_init_memmap(v return 0; } - /* Bound memory initialisation to a local node if possible */ + /* Bind memory initialisation thread to a local node if possible */ if (!cpumask_empty(cpumask)) set_cpus_allowed_ptr(current, cpumask); @@ -1200,7 +1201,6 @@ void __init page_alloc_init_late(void) { int nid; - init_rwsem(&pgdat_init_rwsem); for_each_node_state(nid, N_MEMORY) { down_read(&pgdat_init_rwsem); kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid); _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
