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| author | Pavel Tatashin <pasha.tatashin@oracle.com> | 2017-05-13 11:02:55 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2017-05-15 11:57:05 +1000 |
| commit | 208ac1862c6163a95b5303a2b5aea9b93c11cccf (patch) | |
| tree | 97e9d9af288107d52df38c0f21778ee50c619b84 | |
| parent | 6825baf00db3434489026733cf6cf24cc39dacf3 (diff) | |
| download | linux-208ac1862c6163a95b5303a2b5aea9b93c11cccf.tar.gz linux-208ac1862c6163a95b5303a2b5aea9b93c11cccf.tar.xz | |
mm: zero hash tables in allocator
Add a new flag HASH_ZERO which when provided grantees that the hash table
that is returned by alloc_large_system_hash() is zeroed. In most cases
that is what is needed by the caller. Use page level allocator's
__GFP_ZERO flags to zero the memory. It is using memset() which is
efficient method to zero memory and is optimized for most platforms.
Link: http://lkml.kernel.org/r/1488432825-92126-3-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/bootmem.h | 1 | ||||
| -rw-r--r-- | mm/page_alloc.c | 12 |
2 files changed, 10 insertions, 3 deletions
diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h index 962164d36506..e223d91b6439 100644 --- a/include/linux/bootmem.h +++ b/include/linux/bootmem.h @@ -358,6 +358,7 @@ extern void *alloc_large_system_hash(const char *tablename, #define HASH_EARLY 0x00000001 /* Allocating during early boot? */ #define HASH_SMALL 0x00000002 /* sub-page allocation allowed, min * shift passed via *_hash_shift */ +#define HASH_ZERO 0x00000004 /* Zero allocated hash table */ /* Only NUMA needs hash distribution. 64bit NUMA architectures have * sufficient vmalloc space. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7f7b50e03d4f..dda1057efaea 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7192,6 +7192,7 @@ void *__init alloc_large_system_hash(const char *tablename, unsigned long long max = high_limit; unsigned long log2qty, size; void *table = NULL; + gfp_t gfp_flags; /* allow the kernel cmdline to have a say */ if (!numentries) { @@ -7236,12 +7237,17 @@ void *__init alloc_large_system_hash(const char *tablename, log2qty = ilog2(numentries); + /* + * memblock allocator returns zeroed memory already, so HASH_ZERO is + * currently not used when HASH_EARLY is specified. + */ + gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC; do { size = bucketsize << log2qty; if (flags & HASH_EARLY) table = memblock_virt_alloc_nopanic(size, 0); else if (hashdist) - table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL); + table = __vmalloc(size, gfp_flags, PAGE_KERNEL); else { /* * If bucketsize is not a power-of-two, we may free @@ -7249,8 +7255,8 @@ void *__init alloc_large_system_hash(const char *tablename, * alloc_pages_exact() automatically does */ if (get_order(size) < MAX_ORDER) { - table = alloc_pages_exact(size, GFP_ATOMIC); - kmemleak_alloc(table, size, 1, GFP_ATOMIC); + table = alloc_pages_exact(size, gfp_flags); + kmemleak_alloc(table, size, 1, gfp_flags); } } } while (!table && size > PAGE_SIZE && --log2qty); |