view src/core/ngx_murmurhash.c @ 6445:c9d680b00744

Cache: added watermark to reduce IO load when keys_zone is full. When a keys_zone is full then each next request to the cache is penalized. That is, the cache has to evict older files to get a slot from the keys_zone synchronously. The patch introduces new behavior in this scenario. Manager will try to maintain available free slots in the keys_zone by cleaning old files in the background.
author Dmitry Volyntsev <xeioex@nginx.com>
date Fri, 18 Mar 2016 15:08:21 +0300
parents 203eb026ec07
children f38647c651a8
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/*
 * Copyright (C) Austin Appleby
 */


#include <ngx_config.h>
#include <ngx_core.h>


uint32_t
ngx_murmur_hash2(u_char *data, size_t len)
{
    uint32_t  h, k;

    h = 0 ^ len;

    while (len >= 4) {
        k  = data[0];
        k |= data[1] << 8;
        k |= data[2] << 16;
        k |= data[3] << 24;

        k *= 0x5bd1e995;
        k ^= k >> 24;
        k *= 0x5bd1e995;

        h *= 0x5bd1e995;
        h ^= k;

        data += 4;
        len -= 4;
    }

    switch (len) {
    case 3:
        h ^= data[2] << 16;
    case 2:
        h ^= data[1] << 8;
    case 1:
        h ^= data[0];
        h *= 0x5bd1e995;
    }

    h ^= h >> 13;
    h *= 0x5bd1e995;
    h ^= h >> 15;

    return h;
}