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From: Yue Chen <ycyc321@gmail.com>
Date: Mon, 16 Mar 2015 15:18:53 -0400
Message-ID: <CAKtBrB4czEv29u-t-Hi09vus8tbACew363nqSvWd1z04oL8kXA@mail.gmail.com>
Subject: Hash table in FreeBSD kernel?
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Dear all,

Is there a good hash table implementation for FreeBSD kernel, x86_64? I
tried "uthash", but encountered some memory problems (during HASH_FIND())
when the entry number becomes large. The cause may be my replacements for
the user-space header functions and types are incorrect.

=====================================================================

The userland functions/types need to be replaced:

#include <string.h> /* memcmp,strlen */

#include <stddef.h> /* ptrdiff_t */

#include <stdlib.h> /* exit() */ /*  malloc()  */

=====================================================================

I use:

#include <sys/systm.h>  /* memcmp */

#include <sys/_types.h>

typedef __ptrdiff_t ptrdiff_t;

#include <sys/types.h>

#include <sys/malloc.h>  /* the malloc()  */

------------------------------------------------------------------------------------------------------------------------

size_t strlen(const char *str)

{

    const char *s;

    for (s = str; *s; ++s);

    return(s - str);

}

=====================================================================

Any suggestions for using "uthash" in kernel, or any other alternatives
that I can use? (the FreeBSD kernel's "hash32" function set seems only
support 32-bit key hash)

Best regards and thanks,
Yue