From: "Alastair D'Silva" <alastair@au1.ibm.com>
To: alastair@d-silva.org
Cc: Michal Hocko <mhocko@suse.com>,
David Hildenbrand <david@redhat.com>,
linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Paul Mackerras <paulus@samba.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Qian Cai <cai@lca.pw>, Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org,
Andrew Morton <akpm@linux-foundation.org>,
Allison Randal <allison@lohutok.net>
Subject: [PATCH v2 4/6] powerpc: Chunk calls to flush_dcache_range in arch_*_memory
Date: Tue, 3 Sep 2019 15:23:58 +1000 [thread overview]
Message-ID: <20190903052407.16638-5-alastair@au1.ibm.com> (raw)
In-Reply-To: <20190903052407.16638-1-alastair@au1.ibm.com>
From: Alastair D'Silva <alastair@d-silva.org>
When presented with large amounts of memory being hotplugged
(in my test case, ~890GB), the call to flush_dcache_range takes
a while (~50 seconds), triggering RCU stalls.
This patch breaks up the call into 1GB chunks, calling
cond_resched() inbetween to allow the scheduler to run.
Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
arch/powerpc/mm/mem.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index cd540123874d..854aaea2c6ae 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -104,11 +104,14 @@ int __weak remove_section_mapping(unsigned long start, unsigned long end)
return -ENODEV;
}
+#define FLUSH_CHUNK_SIZE SZ_1G
+
int __ref arch_add_memory(int nid, u64 start, u64 size,
struct mhp_restrictions *restrictions)
{
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
+ u64 i;
int rc;
resize_hpt_for_hotplug(memblock_phys_mem_size());
@@ -120,7 +123,12 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
start, start + size, rc);
return -EFAULT;
}
- flush_dcache_range(start, start + size);
+
+ for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) {
+ flush_dcache_range(start + i,
+ min(start + size, start + i + FLUSH_CHUNK_SIZE));
+ cond_resched();
+ }
return __add_pages(nid, start_pfn, nr_pages, restrictions);
}
@@ -131,13 +139,19 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct page *page = pfn_to_page(start_pfn) + vmem_altmap_offset(altmap);
+ u64 i;
int ret;
__remove_pages(page_zone(page), start_pfn, nr_pages, altmap);
/* Remove htab bolted mappings for this section of memory */
start = (unsigned long)__va(start);
- flush_dcache_range(start, start + size);
+ for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) {
+ flush_dcache_range(start + i,
+ min(start + size, start + i + FLUSH_CHUNK_SIZE));
+ cond_resched();
+ }
+
ret = remove_section_mapping(start, start + size);
WARN_ON_ONCE(ret);
--
2.21.0
next prev parent reply other threads:[~2019-09-03 5:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 5:23 [PATCH v2 0/6] powerpc: convert cache asm to C Alastair D'Silva
2019-09-03 5:23 ` [PATCH v2 1/6] powerpc: Allow flush_icache_range to work across ranges >4GB Alastair D'Silva
2019-09-14 7:46 ` Christophe Leroy
2019-09-16 3:25 ` Alastair D'Silva
2019-09-03 5:23 ` [PATCH v2 2/6] powerpc: define helpers to get L1 icache sizes Alastair D'Silva
2019-09-03 5:23 ` [PATCH v2 3/6] powerpc: Convert flush_icache_range & friends to C Alastair D'Silva
2019-09-03 6:08 ` Christophe Leroy
2019-09-03 11:25 ` Michael Ellerman
2019-09-04 3:23 ` Alastair D'Silva
2019-09-04 13:35 ` Segher Boessenkool
2019-09-03 13:04 ` Segher Boessenkool
2019-09-03 14:28 ` Christophe Leroy
2019-09-03 16:04 ` Segher Boessenkool
2019-09-03 17:05 ` Christophe Leroy
2019-09-03 18:31 ` Segher Boessenkool
2019-09-03 20:11 ` Gabriel Paubert
2019-09-04 3:42 ` Alastair D'Silva
2019-09-04 3:36 ` Alastair D'Silva
2019-09-03 5:23 ` Alastair D'Silva [this message]
2019-09-03 6:19 ` [PATCH v2 4/6] powerpc: Chunk calls to flush_dcache_range in arch_*_memory Christophe Leroy
2019-09-03 6:25 ` Alastair D'Silva
2019-09-03 6:51 ` Christophe Leroy
2019-09-04 4:11 ` Alastair D'Silva
2019-09-03 5:23 ` [PATCH v2 5/6] powerpc: Remove 'extern' from func prototypes in cache headers Alastair D'Silva
2019-09-03 6:21 ` Christophe Leroy
2019-09-03 5:24 ` [PATCH v2 6/6] powerpc: Don't flush caches when adding memory Alastair D'Silva
2019-09-03 6:23 ` Christophe Leroy
2019-09-03 6:27 ` Alastair D'Silva
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