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| author | Alastair D'Silva <alastair@d-silva.org> | 2019-11-04 13:32:57 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-09 10:20:02 +0100 |
| commit | 0e9d2e5f7141cb48a52063a56f73aaa56652ec6b (patch) | |
| tree | 188dd12377a1f6f6a32b4f053d4e99152fd78a9a /arch/powerpc/mm | |
| parent | af8547549041936848c96bc3d5fddcd33ba9c0d2 (diff) | |
| download | linux-stable-0e9d2e5f7141cb48a52063a56f73aaa56652ec6b.tar.gz linux-stable-0e9d2e5f7141cb48a52063a56f73aaa56652ec6b.tar.bz2 linux-stable-0e9d2e5f7141cb48a52063a56f73aaa56652ec6b.zip | |
powerpc: Chunk calls to flush_dcache_range in arch_*_memory
commit 076265907cf9633bbef861c7c2a1c26a8209f283 upstream.
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.
Fixes: fb5924fddf9e ("powerpc/mm: Flush cache on memory hot(un)plug")
Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191104023305.9581-6-alastair@au1.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/mem.c | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 97e5922cb52e..460afa415434 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -104,6 +104,27 @@ int __weak remove_section_mapping(unsigned long start, unsigned long end) return -ENODEV; } +#define FLUSH_CHUNK_SIZE SZ_1G +/** + * flush_dcache_range_chunked(): Write any modified data cache blocks out to + * memory and invalidate them, in chunks of up to FLUSH_CHUNK_SIZE + * Does not invalidate the corresponding instruction cache blocks. + * + * @start: the start address + * @stop: the stop address (exclusive) + * @chunk: the max size of the chunks + */ +static void flush_dcache_range_chunked(unsigned long start, unsigned long stop, + unsigned long chunk) +{ + unsigned long i; + + for (i = start; i < stop; i += chunk) { + flush_dcache_range(i, min(stop, start + chunk)); + cond_resched(); + } +} + int __ref arch_add_memory(int nid, u64 start, u64 size, struct mhp_restrictions *restrictions) { @@ -120,7 +141,8 @@ int __ref arch_add_memory(int nid, u64 start, u64 size, start, start + size, rc); return -EFAULT; } - flush_dcache_range(start, start + size); + + flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE); return __add_pages(nid, start_pfn, nr_pages, restrictions); } @@ -136,7 +158,8 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size, /* Remove htab bolted mappings for this section of memory */ start = (unsigned long)__va(start); - flush_dcache_range(start, start + size); + flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE); + ret = remove_section_mapping(start, start + size); WARN_ON_ONCE(ret); |