Messages in this thread Patch in this message | | | Date | Wed, 13 May 2015 10:53:33 -0500 | From | nzimmer <> | Subject | Re: [PATCH] mm: meminit: Finish initialisation of struct pages before basic setup |
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I am just noticed a hang on my largest box. I can only reproduce with large core counts, if I turn down the number of cpus it doesn't have an issue.
Also as time goes on the amount of time required to initialize pages goes up.
log_uv48_05121052:[ 177.250385] node 0 initialised, 14950072 pages in 544ms log_uv48_05121052:[ 177.269629] node 1 initialised, 15990505 pages in 564ms log_uv48_05121052:[ 177.436047] node 215 initialised, 3600110 pages in 724ms log_uv48_05121052:[ 177.464056] node 102 initialised, 3604205 pages in 756ms log_uv48_05121052:[ 178.073822] node 30 initialised, 7732972 pages in 1368ms log_uv48_05121052:[ 178.082888] node 31 initialised, 7728877 pages in 1372ms log_uv48_05121052:[ 178.080060] node 29 initialised, 7728877 pages in 1376ms .... log_uv48_05121052:[ 178.217980] node 197 initialised, 7728877 pages in 1504ms log_uv48_05121052:[ 178.217851] node 196 initialised, 7732972 pages in 1504ms log_uv48_05121052:[ 178.219992] node 247 initialised, 7726418 pages in 1504ms log_uv48_05121052:[ 178.325299] node 3 initialised, 15986409 pages in 1624ms log_uv48_05121052:[ 178.328455] node 2 initialised, 15990505 pages in 1624ms log_uv48_05121052:[ 178.383371] node 4 initialised, 15990505 pages in 1680ms ... log_uv48_05121052:[ 178.438401] node 19 initialised, 15986409 pages in 1728ms
I apologize for the tardiness of this report but I have not been able to get to the largest boxes reliably. Hopefully I will have more access this week.
On 05/07/2015 05:09 PM, Andrew Morton wrote: > On Thu, 7 May 2015 08:25:18 +0100 Mel Gorman <mgorman@suse.de> 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 <akpm@linux-foundation.org> > 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 <daniel@numascale.com> > Cc: Dave Hansen <dave.hansen@intel.com> > Cc: Mel Gorman <mgorman@suse.de> > Cc: Nathan Zimmer <nzimmer@sgi.com> > Cc: Scott Norton <scott.norton@hp.com> > Cc: Waiman Long <waiman.long@hp.com > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > --- > > 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); > _ >
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