From nobody Tue Oct 28 12:38:31 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1522981118456581.0072439501105; Thu, 5 Apr 2018 19:18:38 -0700 (PDT) Received: from localhost ([::1]:44013 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f4GxZ-0006SL-Gj for importer@patchew.org; Thu, 05 Apr 2018 22:18:37 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58409) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f4GsL-0002G9-5D for qemu-devel@nongnu.org; Thu, 05 Apr 2018 22:13:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f4GsI-0003TC-Ct for qemu-devel@nongnu.org; Thu, 05 Apr 2018 22:13:13 -0400 Received: from out5-smtp.messagingengine.com ([66.111.4.29]:50247) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f4GsI-0003SQ-6k for qemu-devel@nongnu.org; Thu, 05 Apr 2018 22:13:10 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id ADAA7207F3; Thu, 5 Apr 2018 22:13:09 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Thu, 05 Apr 2018 22:13:09 -0400 Received: from localhost (flamenco.cs.columbia.edu [128.59.20.216]) by mail.messagingengine.com (Postfix) with ESMTPA id 63CBDE4F68; Thu, 5 Apr 2018 22:13:09 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=braap.org; h=cc :date:from:in-reply-to:message-id:references:subject:to :x-me-sender:x-me-sender:x-sasl-enc; s=mesmtp; bh=QxvdvE5heYUGio zm8zjz8HRbelnB+/ScJmHQhaPybk8=; b=dY5IBwp4+rlksKenNIW7xS4+1E3CXE V+Ar0pXNOu444DgjT/AB+pMLkod6k4OizYpAJV/bXiGU+ZfRp63lxSO3pkgj/0mN /X7jNXJ6/UmOQ1ChCTrJNiC7f2DofoGSllslkkI/YCWum0vpqjGFbxRnsYgekjAd ld/pUM5ooo58M= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:date:from:in-reply-to:message-id :references:subject:to:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; bh=QxvdvE5heYUGiozm8zjz8HRbelnB+/ScJmHQhaPybk8=; b=GkRkCfaj tN2ccHDGA+dp215MyoP1MeMeBSnfYaOjGVit4NB3/jHMWyepUlUrlY4tsnj31eMV Y3sgjezqQ82JdEWT7AUFygnMfBk5hKxhyHHrmmE/k/a1AI6Nk/DEA5/G6qfVLUwJ AWVsihOZ2NKVuLpFHot3whT6bljmj4G+wnFooh6mclZk3B85HaLBtqTTwU8MrOx+ GzYEw5lyOS+Y5ny+pKaghGzpRc1/eTVG9WlOqKi3fPihB/6iKuVWAWyHbQg+yoGe j7AR08MsYZtynaxfDGLpNaAUPQ2+j70v83LHoBEv3ZDdNNx9INEbj9RfsIjqEHBB avbP1ecW2Hzfcg== X-ME-Sender: From: "Emilio G. Cota" To: qemu-devel@nongnu.org Date: Thu, 5 Apr 2018 22:12:53 -0400 Message-Id: <1522980788-1252-3-git-send-email-cota@braap.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1522980788-1252-1-git-send-email-cota@braap.org> References: <1522980788-1252-1-git-send-email-cota@braap.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.111.4.29 Subject: [Qemu-devel] [PATCH v2 02/17] 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: Richard Henderson , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Paolo Bonzini Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 Signed-off-by: Emilio G. Cota --- 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 5f03a0f..1fb9116 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 7af5f36..d16e094 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1245,7 +1245,7 @@ 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 c94ac25..f492b3a 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 b069881..dda6a06 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 8610ce3..9d030e7 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 2.7.4