mm: define memblock_virt_alloc_try_nid_raw

* A new variant of memblock_virt_alloc_* allocations:
memblock_virt_alloc_try_nid_raw()
    - Does not zero the allocated memory
    - Does not panic if request cannot be satisfied

* optimize early system hash allocations

Clients can call alloc_large_system_hash() with flag: HASH_ZERO to
specify that memory that was allocated for system hash needs to be
zeroed, otherwise the memory does not need to be zeroed, and client will
initialize it.

If memory does not need to be zero'd, call the new
memblock_virt_alloc_raw() interface, and thus improve the boot
performance.

* debug for raw alloctor

When CONFIG_DEBUG_VM is enabled, this patch sets all the memory that is
returned by memblock_virt_alloc_try_nid_raw() to ones to ensure that no
places excpect zeroed memory.

Link: http://lkml.kernel.org/r/20171013173214.27300-6-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4dee5082d3d7..805f30dd1c26 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7313,18 +7313,17 @@ 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)
+                if (flags & HASH_EARLY) {
+                        if (flags & HASH_ZERO)
+                                table = memblock_virt_alloc_nopanic(size, 0);
+                        else
+                                table = memblock_virt_alloc_raw(size, 0);
+                } else if (hashdist) {
                         table = __vmalloc(size, gfp_flags, PAGE_KERNEL);
-                else {
+                } else {
                         /*
                          * If bucketsize is not a power-of-two, we may free
                          * some pages at the end of hash table which