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Date: Fri, 14 Jul 2017 15:16:12 -0700
From: daniel.m.jordan@...cle.com
To: linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [RFC PATCH v1 5/6] mm: parallelize clear_gigantic_page
Parallelize clear_gigantic_page, which zeroes any page size larger than
8M (e.g. 1G on x86 or 2G on SPARC).
Performance results (the default number of threads is 4; higher thread
counts shown for context only):
Machine: SPARC T7-4, 1024 cpus, 504G memory
Test: Clear a range of gigantic pages
nthread speedup size (GiB) min time (s) stdev
1 50 7.77 0.02
2 1.97x 50 3.95 0.04
4 3.85x 50 2.02 0.05
8 6.27x 50 1.24 0.10
16 9.84x 50 0.79 0.06
1 100 15.50 0.07
2 1.91x 100 8.10 0.05
4 3.48x 100 4.45 0.07
8 5.18x 100 2.99 0.05
16 7.79x 100 1.99 0.12
1 200 31.03 0.15
2 1.88x 200 16.47 0.02
4 3.37x 200 9.20 0.14
8 5.16x 200 6.01 0.19
16 7.04x 200 4.41 0.06
Machine: Intel(R) Xeon(R) CPU E7-8895 v3 @ 2.60GHz, 288 cpus, 1T memory
Test: Clear a range of gigantic pages
nthread speedup size (GiB) min time (s) stdev
1 100 41.13 0.03
2 2.03x 100 20.26 0.14
4 4.28x 100 9.62 0.09
8 8.39x 100 4.90 0.05
16 10.44x 100 3.94 0.03
1 200 89.68 0.35
2 2.21x 200 40.64 0.18
4 4.64x 200 19.33 0.32
8 8.99x 200 9.98 0.04
16 11.27x 200 7.96 0.04
1 400 188.20 1.57
2 2.30x 400 81.84 0.09
4 4.63x 400 40.62 0.26
8 8.92x 400 21.09 0.50
16 11.78x 400 15.97 0.25
1 800 434.91 1.81
2 2.54x 800 170.97 1.46
4 4.98x 800 87.38 1.91
8 10.15x 800 42.86 2.59
16 12.99x 800 33.48 0.83
Signed-off-by: Daniel Jordan <daniel.m.jordan@...cle.com>
---
mm/memory.c | 35 +++++++++++++++++++++++++++--------
1 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index bb11c47..073745f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -68,6 +68,7 @@
#include <linux/debugfs.h>
#include <linux/userfaultfd_k.h>
#include <linux/dax.h>
+#include <linux/ktask.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
@@ -4294,27 +4295,45 @@ void __might_fault(const char *file, int line)
#endif
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
-static void clear_gigantic_page(struct page *page,
- unsigned long addr,
- unsigned int pages_per_huge_page)
+
+struct cgp_args {
+ struct page *base_page;
+ unsigned long addr;
+};
+
+static int clear_gigantic_page_chunk(unsigned long start, unsigned long end,
+ struct cgp_args *args)
{
- int i;
- struct page *p = page;
+ struct page *base_page = args->base_page;
+ struct page *p = base_page;
+ unsigned long addr = args->addr;
+ unsigned long i;
might_sleep();
- for (i = 0; i < pages_per_huge_page;
- i++, p = mem_map_next(p, page, i)) {
+ for (i = start; i < end; ++i) {
cond_resched();
clear_user_highpage(p, addr + i * PAGE_SIZE);
+
+ p = mem_map_next(p, base_page, i);
}
+
+ return KTASK_RETURN_SUCCESS;
}
+
void clear_huge_page(struct page *page,
unsigned long addr, unsigned int pages_per_huge_page)
{
int i;
if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
- clear_gigantic_page(page, addr, pages_per_huge_page);
+ struct cgp_args args = {page, addr};
+ struct ktask_node node = {0, pages_per_huge_page,
+ page_to_nid(page)};
+ DEFINE_KTASK_CTL_RANGE(ctl, clear_gigantic_page_chunk, &args,
+ KTASK_BPGS_MINCHUNK, GFP_KERNEL, 0);
+
+ ktask_run_numa(&node, 1, &ctl);
+
return;
}
--
1.7.1
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