Commit 61b8cef1 authored by Emilio G. Cota's avatar Emilio G. Cota Committed by Richard Henderson
Browse files

qht: require a default comparison function 



qht_lookup now uses the default cmp function. qht_lookup_custom is defined
to retain the old behaviour, that is a cmp function is explicitly provided.

qht_insert will gain use of the default cmp in the next patch.

Note that we move qht_lookup_custom's @func to be the last argument,
which makes the new qht_lookup as simple as possible.
Instead of this (i.e. keeping @func 2nd):
0000000000010750 <qht_lookup>:
   10750:       89 d1                   mov    %edx,%ecx
   10752:       48 89 f2                mov    %rsi,%rdx
   10755:       48 8b 77 08             mov    0x8(%rdi),%rsi
   10759:       e9 22 ff ff ff          jmpq   10680 <qht_lookup_custom>
   1075e:       66 90                   xchg   %ax,%ax

We get:
0000000000010740 <qht_lookup>:
   10740:       48 8b 4f 08             mov    0x8(%rdi),%rcx
   10744:       e9 37 ff ff ff          jmpq   10680 <qht_lookup_custom>
   10749:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)

Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: default avatarEmilio G. Cota <cota@braap.org>
Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent 1019242a

accel/tcg/cpu-exec.c

+2 −2
Original line number Diff line number Diff line
@@ -295,7 +295,7 @@ struct tb_desc { 
    uint32_t trace_vcpu_dstate;

};



static bool tb_cmp(const void *p, const void *d)

static bool tb_lookup_cmp(const void *p, const void *d)

{

    const TranslationBlock *tb = p;

    const struct tb_desc *desc = d;
@@ -340,7 +340,7 @@ TranslationBlock *tb_htable_lookup(CPUState *cpu, target_ulong pc, 
    phys_pc = get_page_addr_code(desc.env, pc);

    desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;

    h = tb_hash_func(phys_pc, pc, flags, cf_mask, *cpu->trace_dstate);

    return qht_lookup(&tb_ctx.htable, tb_cmp, &desc, h);

    return qht_lookup_custom(&tb_ctx.htable, &desc, h, tb_lookup_cmp);

}



void tb_set_jmp_target(TranslationBlock *tb, int n, uintptr_t addr)

accel/tcg/translate-all.c

+15 −1
Original line number Diff line number Diff line
@@ -782,11 +782,25 @@ static inline void code_gen_alloc(size_t tb_size) 
    qemu_mutex_init(&tb_ctx.tb_lock);

}



static bool tb_cmp(const void *ap, const void *bp)

{

    const TranslationBlock *a = ap;

    const TranslationBlock *b = bp;



    return a->pc == b->pc &&

        a->cs_base == b->cs_base &&

        a->flags == b->flags &&

        (tb_cflags(a) & CF_HASH_MASK) == (tb_cflags(b) & CF_HASH_MASK) &&

        a->trace_vcpu_dstate == b->trace_vcpu_dstate &&

        a->page_addr[0] == b->page_addr[0] &&

        a->page_addr[1] == b->page_addr[1];

}



static void tb_htable_init(void)

{

    unsigned int mode = QHT_MODE_AUTO_RESIZE;



    qht_init(&tb_ctx.htable, CODE_GEN_HTABLE_SIZE, mode);

    qht_init(&tb_ctx.htable, tb_cmp, CODE_GEN_HTABLE_SIZE, mode);

}



/* Must be called before using the QEMU cpus. 'tb_size' is the size

include/qemu/qht.h

+20 −5
Original line number Diff line number Diff line
@@ -11,8 +11,11 @@ 
#include "qemu/thread.h"

#include "qemu/qdist.h"



typedef bool (*qht_cmp_func_t)(const void *a, const void *b);



struct qht {

    struct qht_map *map;

    qht_cmp_func_t cmp;

    QemuMutex lock; /* serializes setters of ht->map */

    unsigned int mode;

};
@@ -47,10 +50,12 @@ typedef void (*qht_iter_func_t)(struct qht *ht, void *p, uint32_t h, void *up); 
/**

 * qht_init - Initialize a QHT

 * @ht: QHT to be initialized

 * @cmp: default comparison function. Cannot be NULL.

 * @n_elems: number of entries the hash table should be optimized for.

 * @mode: bitmask with OR'ed QHT_MODE_*

 */

void qht_init(struct qht *ht, size_t n_elems, unsigned int mode);

void qht_init(struct qht *ht, qht_cmp_func_t cmp, size_t n_elems,

              unsigned int mode);



/**

 * qht_destroy - destroy a previously initialized QHT
@@ -78,11 +83,11 @@ void qht_destroy(struct qht *ht); 
bool qht_insert(struct qht *ht, void *p, uint32_t hash);



/**

 * qht_lookup - Look up a pointer in a QHT

 * qht_lookup_custom - Look up a pointer using a custom comparison function.

 * @ht: QHT to be looked up

 * @func: function to compare existing pointers against @userp

 * @userp: pointer to pass to @func

 * @hash: hash of the pointer to be looked up

 * @func: function to compare existing pointers against @userp

 *

 * Needs to be called under an RCU read-critical section.

 *
@@ -94,8 +99,18 @@ bool qht_insert(struct qht *ht, void *p, uint32_t hash); 
 * Returns the corresponding pointer when a match is found.

 * Returns NULL otherwise.

 */

void *qht_lookup(struct qht *ht, qht_lookup_func_t func, const void *userp,

                 uint32_t hash);

void *qht_lookup_custom(struct qht *ht, const void *userp, uint32_t hash,

                        qht_lookup_func_t func);



/**

 * qht_lookup - Look up a pointer in a QHT

 * @ht: QHT to be looked up

 * @userp: pointer to pass to the comparison function

 * @hash: hash of the pointer to be looked up

 *

 * Calls qht_lookup_custom() using @ht's default comparison function.

 */

void *qht_lookup(struct qht *ht, const void *userp, uint32_t hash);



/**

 * qht_remove - remove a pointer from the hash table

tests/qht-bench.c

+7 −7
Original line number Diff line number Diff line
@@ -93,10 +93,10 @@ static void usage_complete(int argc, char *argv[]) 
    exit(-1);

}



static bool is_equal(const void *obj, const void *userp)

static bool is_equal(const void *ap, const void *bp)

{

    const long *a = obj;

    const long *b = userp;

    const long *a = ap;

    const long *b = bp;



    return *a == *b;

}
@@ -150,7 +150,7 @@ static void do_rw(struct thread_info *info) 


        p = &keys[info->r & (lookup_range - 1)];

        hash = h(*p);

        read = qht_lookup(&ht, is_equal, p, hash);

        read = qht_lookup(&ht, p, hash);

        if (read) {

            stats->rd++;

        } else {
@@ -162,7 +162,7 @@ static void do_rw(struct thread_info *info) 
        if (info->write_op) {

            bool written = false;



            if (qht_lookup(&ht, is_equal, p, hash) == NULL) {

            if (qht_lookup(&ht, p, hash) == NULL) {

                written = qht_insert(&ht, p, hash);

            }

            if (written) {
@@ -173,7 +173,7 @@ static void do_rw(struct thread_info *info) 
        } else {

            bool removed = false;



            if (qht_lookup(&ht, is_equal, p, hash)) {

            if (qht_lookup(&ht, p, hash)) {

                removed = qht_remove(&ht, p, hash);

            }

            if (removed) {
@@ -308,7 +308,7 @@ static void htable_init(void) 
    }



    /* initialize the hash table */

    qht_init(&ht, qht_n_elems, qht_mode);

    qht_init(&ht, is_equal, qht_n_elems, qht_mode);

    assert(init_size <= init_range);



    pr_params();

tests/test-qht.c

+10 −5
Original line number Diff line number Diff line
@@ -13,10 +13,10 @@ 
static struct qht ht;

static int32_t arr[N * 2];



static bool is_equal(const void *obj, const void *userp)

static bool is_equal(const void *ap, const void *bp)

{

    const int32_t *a = obj;

    const int32_t *b = userp;

    const int32_t *a = ap;

    const int32_t *b = bp;



    return *a == *b;

}
@@ -60,7 +60,12 @@ static void check(int a, int b, bool expected) 


        val = i;

        hash = i;

        p = qht_lookup(&ht, is_equal, &val, hash);

        /* test both lookup variants; results should be the same */

        if (i % 2) {

            p = qht_lookup(&ht, &val, hash);

        } else {

            p = qht_lookup_custom(&ht, &val, hash, is_equal);

        }

        g_assert_true(!!p == expected);

    }

    rcu_read_unlock();
@@ -102,7 +107,7 @@ static void qht_do_test(unsigned int mode, size_t init_entries) 
    /* under KVM we might fetch stats from an uninitialized qht */

    check_n(0);



    qht_init(&ht, 0, mode);

    qht_init(&ht, is_equal, 0, mode);



    check_n(0);

    insert(0, N);