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[173.198.77.219]) by smtp.gmail.com with ESMTPSA id x24-v6sm11532184pfj.104.2018.06.14.12.31.55 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 14 Jun 2018 12:31:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=0ifFvg47P31SiqVLHK249PSF/Xw/scsIziiDtRJNjko=; b=GLHx49/zPCGzimPZgIpOxzvV/uh8LnXRBoYVC/r86kQoC0OxGksZEb8aZfHnRytzPi fm9IFybwumTTWznaM4z1wXT6GPotxKWMzCnddXUydc2LnrheKTSCf3EcS0KMrCCnHfIa YVHfU5lz7MdgatvAZIqI5CdQ4LLMpk41rFBgU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=0ifFvg47P31SiqVLHK249PSF/Xw/scsIziiDtRJNjko=; b=dJhNWOhgFB/lPR/a98kZiy98T/aZ/GYwM2F8xagyGVC/u7CJzsm92pbRe8H4lzVKiJ b337gvqomiV66EoTT61tN8GRhIRjiTb9uqynBh8wI72cAQ1vD0xVEQHLj3P64WGzrKTG sPKLJcQuoO2cX4zjU1H5ES4jtgmsSUuFUUhSsZSfuFEiHTD6y2BvYkJe8qNDZV5ZAiIF m5zSAuz/YIcEQMeILgUlG35R90EevZaM5VJ2gj0V20DK7ThSM/ODJjpeXdmqr5ABRzJ7 zqAyZtRhZFiIZvOvD3yZGHJaeCcAuUbBXfSuDzALtM1b/ng/NY9gmRqoqIurZET55N4T QxWA== X-Gm-Message-State: APt69E0sRMdMBnZmfvyn9DnQhw0wRuDxrEuopf/2YfvTpUbPWZKLjKFy Bwju3EI4uQzY2PCiWg+kC4Azf1ompXA= X-Google-Smtp-Source: ADUXVKKvaQzSgIgvJyqxfp9zoKpt9qyevrqGQnVX7/qENcnqny2AsTpQpmCGaEv7dj4qiY93JezHOQ== X-Received: by 2002:a62:e401:: with SMTP id r1-v6mr10817705pfh.172.1529004717298; Thu, 14 Jun 2018 12:31:57 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Thu, 14 Jun 2018 09:31:32 -1000 Message-Id: <20180614193147.29680-4-richard.henderson@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180614193147.29680-1-richard.henderson@linaro.org> References: <20180614193147.29680-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:400e:c05::22a Subject: [Qemu-devel] [PULL 03/18] qht: return existing entry when qht_insert fails X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, "Emilio G. Cota" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZohoMail: RDKM_2 RSF_0 Z_629925259 SPT_0 From: "Emilio G. Cota" The meaning of "existing" is now changed to "matches in hash and ht->cmp result". This is saner than just checking the pointer value. Suggested-by: Richard Henderson Reviewed-by: Richard Henderson Reviewed-by: Alex Benn=C3=A9e Signed-off-by: Emilio G. Cota Signed-off-by: Richard Henderson --- include/qemu/qht.h | 7 +++++-- accel/tcg/translate-all.c | 2 +- tests/qht-bench.c | 4 ++-- tests/test-qht.c | 8 +++++++- util/qht.c | 27 +++++++++++++++++---------- 5 files changed, 32 insertions(+), 16 deletions(-) diff --git a/include/qemu/qht.h b/include/qemu/qht.h index 5f03a0f4cb..1fb9116fa0 100644 --- a/include/qemu/qht.h +++ b/include/qemu/qht.h @@ -70,6 +70,7 @@ void qht_destroy(struct qht *ht); * @ht: QHT to insert to * @p: pointer to be inserted * @hash: hash corresponding to @p + * @existing: address where the pointer to an existing entry can be copied= to * * Attempting to insert a NULL @p is a bug. * Inserting the same pointer @p with different @hash values is a bug. @@ -78,9 +79,11 @@ void qht_destroy(struct qht *ht); * inserted into the hash table. * * Returns true on success. - * Returns false if the @p-@hash pair already exists in the hash table. + * Returns false if there is an existing entry in the table that is equiva= lent + * (i.e. ht->cmp matches and the hash is the same) to @p-@h. If @existing + * is !NULL, a pointer to this existing entry is copied to it. */ -bool qht_insert(struct qht *ht, void *p, uint32_t hash); +bool qht_insert(struct qht *ht, void *p, uint32_t hash, void **existing); =20 /** * qht_lookup_custom - Look up a pointer using a custom comparison functio= n. diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index f39123bd5a..1695f8c352 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1242,7 +1242,7 @@ static void tb_link_page(TranslationBlock *tb, tb_pag= e_addr_t phys_pc, /* add in the hash table */ h =3D tb_hash_func(phys_pc, tb->pc, tb->flags, tb->cflags & CF_HASH_MA= SK, tb->trace_vcpu_dstate); - qht_insert(&tb_ctx.htable, tb, h); + qht_insert(&tb_ctx.htable, tb, h, NULL); =20 #ifdef CONFIG_USER_ONLY if (DEBUG_TB_CHECK_GATE) { diff --git a/tests/qht-bench.c b/tests/qht-bench.c index c94ac25158..f492b3a20a 100644 --- a/tests/qht-bench.c +++ b/tests/qht-bench.c @@ -163,7 +163,7 @@ static void do_rw(struct thread_info *info) bool written =3D false; =20 if (qht_lookup(&ht, p, hash) =3D=3D NULL) { - written =3D qht_insert(&ht, p, hash); + written =3D qht_insert(&ht, p, hash, NULL); } if (written) { stats->in++; @@ -322,7 +322,7 @@ static void htable_init(void) r =3D xorshift64star(r); p =3D &keys[r & (init_range - 1)]; hash =3D h(*p); - if (qht_insert(&ht, p, hash)) { + if (qht_insert(&ht, p, hash, NULL)) { break; } retries++; diff --git a/tests/test-qht.c b/tests/test-qht.c index b069881342..dda6a067be 100644 --- a/tests/test-qht.c +++ b/tests/test-qht.c @@ -27,11 +27,17 @@ static void insert(int a, int b) =20 for (i =3D a; i < b; i++) { uint32_t hash; + void *existing; + bool inserted; =20 arr[i] =3D i; hash =3D i; =20 - qht_insert(&ht, &arr[i], hash); + inserted =3D qht_insert(&ht, &arr[i], hash, NULL); + g_assert_true(inserted); + inserted =3D qht_insert(&ht, &arr[i], hash, &existing); + g_assert_false(inserted); + g_assert_true(existing =3D=3D &arr[i]); } } =20 diff --git a/util/qht.c b/util/qht.c index 8610ce3644..9d030e7b76 100644 --- a/util/qht.c +++ b/util/qht.c @@ -511,9 +511,9 @@ void *qht_lookup(struct qht *ht, const void *userp, uin= t32_t hash) } =20 /* call with head->lock held */ -static bool qht_insert__locked(struct qht *ht, struct qht_map *map, - struct qht_bucket *head, void *p, uint32_t = hash, - bool *needs_resize) +static void *qht_insert__locked(struct qht *ht, struct qht_map *map, + struct qht_bucket *head, void *p, uint32_t= hash, + bool *needs_resize) { struct qht_bucket *b =3D head; struct qht_bucket *prev =3D NULL; @@ -523,8 +523,9 @@ static bool qht_insert__locked(struct qht *ht, struct q= ht_map *map, do { for (i =3D 0; i < QHT_BUCKET_ENTRIES; i++) { if (b->pointers[i]) { - if (unlikely(b->pointers[i] =3D=3D p)) { - return false; + if (unlikely(b->hashes[i] =3D=3D hash && + ht->cmp(b->pointers[i], p))) { + return b->pointers[i]; } } else { goto found; @@ -553,7 +554,7 @@ static bool qht_insert__locked(struct qht *ht, struct q= ht_map *map, atomic_set(&b->hashes[i], hash); atomic_set(&b->pointers[i], p); seqlock_write_end(&head->sequence); - return true; + return NULL; } =20 static __attribute__((noinline)) void qht_grow_maybe(struct qht *ht) @@ -577,25 +578,31 @@ static __attribute__((noinline)) void qht_grow_maybe(= struct qht *ht) qemu_mutex_unlock(&ht->lock); } =20 -bool qht_insert(struct qht *ht, void *p, uint32_t hash) +bool qht_insert(struct qht *ht, void *p, uint32_t hash, void **existing) { struct qht_bucket *b; struct qht_map *map; bool needs_resize =3D false; - bool ret; + void *prev; =20 /* NULL pointers are not supported */ qht_debug_assert(p); =20 b =3D qht_bucket_lock__no_stale(ht, hash, &map); - ret =3D qht_insert__locked(ht, map, b, p, hash, &needs_resize); + prev =3D qht_insert__locked(ht, map, b, p, hash, &needs_resize); qht_bucket_debug__locked(b); qemu_spin_unlock(&b->lock); =20 if (unlikely(needs_resize) && ht->mode & QHT_MODE_AUTO_RESIZE) { qht_grow_maybe(ht); } - return ret; + if (likely(prev =3D=3D NULL)) { + return true; + } + if (existing) { + *existing =3D prev; + } + return false; } =20 static inline bool qht_entry_is_last(struct qht_bucket *b, int pos) --=20 2.17.1