From patchwork Mon May 21 23:39:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Emilio Cota X-Patchwork-Id: 10417073 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C77D96053B for ; Mon, 21 May 2018 23:50:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B9CE128A16 for ; Mon, 21 May 2018 23:50:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B89E128A46; Mon, 21 May 2018 23:50:35 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 1FE9328AE8 for ; Mon, 21 May 2018 23:50:35 +0000 (UTC) Received: from localhost ([::1]:52904 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fKuZW-0002mE-AX for patchwork-qemu-devel@patchwork.kernel.org; Mon, 21 May 2018 19:50:34 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57824) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fKuOt-0002eE-5D for qemu-devel@nongnu.org; Mon, 21 May 2018 19:39:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fKuOo-0005Wk-Ih for qemu-devel@nongnu.org; Mon, 21 May 2018 19:39:35 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:37515) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fKuOo-0005Uw-EY for qemu-devel@nongnu.org; Mon, 21 May 2018 19:39:30 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id D01A82255B; Mon, 21 May 2018 19:39:28 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Mon, 21 May 2018 19:39:28 -0400 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=0JfffYvJT/zi+m aTtE4fKFjRujGvnAj4XAZ6tBk7m0s=; b=xAQyLgg1pw2p3+/mXP0uBwmsxQIFRX FtbrfFQApVTCJW3Ma/PFkkk5jESlMGQZWhC1vo0lcTDjDgJvLaa7CG85/QVOT4oI BUnYPS84ZZNqrfLlv2kKeI/DUOF531nFWVVRxKbrrfYMYHobUFLCPFCN7TzbiL2w IP7tjZlF1xmyM= 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=0JfffYvJT/zi+maTtE4fKFjRujGvnAj4XAZ6tBk7m0s=; b=AVpvjXYq GOd3tjYw21j1AKA64IPePRb43C6hIJQLXD7iBx4jsGBXKxZ0u3tBxazbaMfxm4E2 vjLt2R23q9UCvvAUxnxX0VKNW12U2Sya6NSQLiGKA0gnew34pRUYl8p5wWggthoA DuGwMDbdRHL7ENILigsgY27xE9qqE/e9NWt86Fv9Jil06soW26z4IT6r2Vw5hgwa zlEBFZ6GHTXSFn9fcTG8xVnZUcZGAFAihE24Jv7sKZRoTEnCxcRCF/vDtmZaB4lb 2331lByaLfgvpcPnQq81rM4n1a5iGTmWr8Vv7lyCuv3OZpVvRztfy/tUPtzaBfYj 9evCXqNN+h9jpw== X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Sender: Received: from localhost (flamenco.cs.columbia.edu [128.59.20.216]) by mail.messagingengine.com (Postfix) with ESMTPA id 7EFB0E4119; Mon, 21 May 2018 19:39:28 -0400 (EDT) From: "Emilio G. Cota" To: qemu-devel@nongnu.org Date: Mon, 21 May 2018 19:39:12 -0400 Message-Id: <1526945967-9687-3-git-send-email-cota@braap.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1526945967-9687-1-git-send-email-cota@braap.org> References: <1526945967-9687-1-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: 66.111.4.25 Subject: [Qemu-devel] [PATCH v3 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: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Richard Henderson , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 Reviewed-by: Alex Bennée --- 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 equivalent + * (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); /** * qht_lookup_custom - Look up a pointer using a custom comparison function. diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index 5b7b91d..8080eb7 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_page_addr_t phys_pc, /* add in the hash table */ h = tb_hash_func(phys_pc, tb->pc, tb->flags, tb->cflags & CF_HASH_MASK, tb->trace_vcpu_dstate); - qht_insert(&tb_ctx.htable, tb, h); + qht_insert(&tb_ctx.htable, tb, h, NULL); #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 = false; if (qht_lookup(&ht, p, hash) == NULL) { - written = qht_insert(&ht, p, hash); + written = qht_insert(&ht, p, hash, NULL); } if (written) { stats->in++; @@ -322,7 +322,7 @@ static void htable_init(void) r = xorshift64star(r); p = &keys[r & (init_range - 1)]; hash = 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) for (i = a; i < b; i++) { uint32_t hash; + void *existing; + bool inserted; arr[i] = i; hash = i; - qht_insert(&ht, &arr[i], hash); + inserted = qht_insert(&ht, &arr[i], hash, NULL); + g_assert_true(inserted); + inserted = qht_insert(&ht, &arr[i], hash, &existing); + g_assert_false(inserted); + g_assert_true(existing == &arr[i]); } } 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, uint32_t hash) } /* 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 = head; struct qht_bucket *prev = NULL; @@ -523,8 +523,9 @@ static bool qht_insert__locked(struct qht *ht, struct qht_map *map, do { for (i = 0; i < QHT_BUCKET_ENTRIES; i++) { if (b->pointers[i]) { - if (unlikely(b->pointers[i] == p)) { - return false; + if (unlikely(b->hashes[i] == 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 qht_map *map, atomic_set(&b->hashes[i], hash); atomic_set(&b->pointers[i], p); seqlock_write_end(&head->sequence); - return true; + return NULL; } 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); } -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 = false; - bool ret; + void *prev; /* NULL pointers are not supported */ qht_debug_assert(p); b = qht_bucket_lock__no_stale(ht, hash, &map); - ret = qht_insert__locked(ht, map, b, p, hash, &needs_resize); + prev = qht_insert__locked(ht, map, b, p, hash, &needs_resize); qht_bucket_debug__locked(b); qemu_spin_unlock(&b->lock); if (unlikely(needs_resize) && ht->mode & QHT_MODE_AUTO_RESIZE) { qht_grow_maybe(ht); } - return ret; + if (likely(prev == NULL)) { + return true; + } + if (existing) { + *existing = prev; + } + return false; } static inline bool qht_entry_is_last(struct qht_bucket *b, int pos)