libbb/yescrypt: madvise(MADV_HUGEPAGE) our usually very large allocation

Nearly ~2 faster run when buffer is gigabytes in size

function                                             old     new   delta
yescrypt_kdf32_body                                 1386    1406     +20

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/libbb/yescrypt/alg-yescrypt-kdf.c b/libbb/yescrypt/alg-yescrypt-kdf.c
index ab095eae1..4c2cfe849 100644
--- a/libbb/yescrypt/alg-yescrypt-kdf.c
+++ b/libbb/yescrypt/alg-yescrypt-kdf.c
@@ -832,14 +832,25 @@ static void smix(uint8_t *B, size_t r, uint32_t N, uint32_t p, uint32_t t,
 
 static void alloc_region(yescrypt_region_t *region, size_t size)
 {
+        uint8_t *base;
         int flags =
 # ifdef MAP_NOCORE /* huh? */
                 MAP_NOCORE |
 # endif
                 MAP_ANON | MAP_PRIVATE;
-        uint8_t *base = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, -1, 0);
+
+        base = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, -1, 0);
         if (base == MAP_FAILED)
                 bb_die_memory_exhausted();
+
+#if defined(MADV_HUGEPAGE)
+        /* Reduces mkpasswd qweRTY123@-+ '$y$jHT$123'
+         * (which allocates 4 Gbytes)
+         * run time from 10.543s to 5.635s
+         * Seen on linux-5.18.0.
+         */
+        madvise(base, size, MADV_HUGEPAGE);
+#endif
         //region->base = base;
         //region->base_size = size;
         region->aligned = base;
@@ -960,7 +971,7 @@ static int yescrypt_kdf32_body(
         if (yctx->local->aligned_size < need) {
                 free_region(yctx->local);
                 alloc_region(yctx->local, need);
-                dbg("allocated local:%u 0x%x", need, need);
+                dbg("allocated local:%lu 0x%lx", (long)need, (long)need);
                 /* standard "j9T" params allocate 16Mbytes here */
         }
         if (flags & YESCRYPT_ALLOC_ONLY)