From nobody Mon Aug 19 11:03:30 2024 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4WnV826dX6z5Sp4G; Mon, 19 Aug 2024 11:03:30 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R11" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4WnV8232pTz4SJl; Mon, 19 Aug 2024 11:03:30 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1724065410; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=aWpjo1Qa0JlWKelNRak1F1cukWCbaVw7q7/oSpHu3gI=; b=Gohhvc8ZEePr40eov9JQ1i6QfcK6TgMrxeGaSYrst0URuizdfkm7kICwKuvBfikosIGJUo iWDZ8kVP1+e10ggat4ifmb7eeLD4yJDGk596e38RraN9TvLUjOmRoIBFU5KE/TKPfbXHFS WAH+V+8smzMb8E4qDpjPBEOgvCxFUTuDzr3MPpojwtO0CSCUFNrFciKI0qryWhg6u21nNH ev4hsj24bvHb31Vu6HexBCIEqcH0io3vY63RFuP5tKOktczA946g9s1v4nEHmMTqx/l1pz 2uKTlvpbEoLtG1rMwNq5dI+b+MKrbly4P8Axdwf/Qr7LjwOuWnrexnvXf9jNsQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1724065410; a=rsa-sha256; cv=none; b=Jjxo0kOhY8sXHBD7ecwXvpJtT2FqN5x1PP4sJj843d2vgOxOK2OJNInrpubIz+Y5YsIfOu Vlq1w68uqQaR+k2CPfkGkSz/jpy3RkyKRCEIimzuZuYaLPen47eoB307gCME74My8Y75ty RHvEliDNqnDPvsPX+SSv24V6DXVex/bBC1fdxuA5rVAQaMFUan7bif4StBCL5Y62yLFLWE SrzqV52GYWJqjQLuJgYfao7UJ8bmkD3AN7lGwXdNd/Izdo8O836lJc7YCx/ocJ9+TPnnEC ubeWjxW1RMCf/f8HF4MoHPSF0/dLbZKjzuuoWYTMZAwOstPgJDxg/q7rHRw69w== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1724065410; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=aWpjo1Qa0JlWKelNRak1F1cukWCbaVw7q7/oSpHu3gI=; b=WOHU8lWKJxX/v5Qh2qb1kdmHcI4AMcC6TTuFFhBeIuwDeEtH6wa8nrgI3D++UJsgsQZ3wd hcuKTGvMB/SKGr9IhTOpFgLG1kVw0KoQpAhOTYsmuRgQQ7OWOYP5kz68zVqhfZF1C2TPyl km5Z6HwE93OVVgqLP5HRhdPOb7Piofa7spoZ+f3up9IT1WjekzgW1bM2Z9YzUzQoGyITEx eTHxrheLM5WNi8H6lCNfJKChfMHYDbf9Pz13EriUSlGvBAqUig+RLYmHWkQIU++4bY5oVa kF2CfdTjtM++CzKrNnAwl2TR9l5BwEoZwH2S6TdbeVnJb8Z3eQq6tQcVJk2bXQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4WnV822DmdzF9p; Mon, 19 Aug 2024 11:03:30 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 47JB3UWL037690; Mon, 19 Aug 2024 11:03:30 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 47JB3UqY037687; Mon, 19 Aug 2024 11:03:30 GMT (envelope-from git) Date: Mon, 19 Aug 2024 11:03:30 GMT Message-Id: <202408191103.47JB3UqY037687@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Andrew Turner Subject: git: 7eb0fffc7792 - main - buf_ring: Remove old arm-only dequeue code List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: andrew X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 7eb0fffc7792bc294d6b86546a3923e2e2f83f8a Auto-Submitted: auto-generated The branch main has been updated by andrew: URL: https://cgit.FreeBSD.org/src/commit/?id=7eb0fffc7792bc294d6b86546a3923e2e2f83f8a commit 7eb0fffc7792bc294d6b86546a3923e2e2f83f8a Author: Andrew Turner AuthorDate: 2024-08-19 09:07:10 +0000 Commit: Andrew Turner CommitDate: 2024-08-19 10:53:11 +0000 buf_ring: Remove old arm-only dequeue code In the single consumer dequeue the consumer thread controls br_cons_head. As such no ordering between this and other data are required. Reviewed by: alc, imp, kib, markj Sponsored by: Arm Ltd Differential Revision: https://reviews.freebsd.org/D46153 --- sys/sys/buf_ring.h | 29 ----------------------------- 1 file changed, 29 deletions(-) diff --git a/sys/sys/buf_ring.h b/sys/sys/buf_ring.h index 9aeb5aa19fa8..ad463fba27cb 100644 --- a/sys/sys/buf_ring.h +++ b/sys/sys/buf_ring.h @@ -177,37 +177,8 @@ buf_ring_dequeue_sc(struct buf_ring *br) uint32_t prod_tail, mask; void *buf; - /* - * This is a workaround to allow using buf_ring on ARM and ARM64. - * ARM64TODO: Fix buf_ring in a generic way. - * REMARKS: It is suspected that br_cons_head does not require - * load_acq operation, but this change was extensively tested - * and confirmed it's working. To be reviewed once again in - * FreeBSD-12. - * - * Preventing following situation: - - * Core(0) - buf_ring_enqueue() Core(1) - buf_ring_dequeue_sc() - * ----------------------------------------- ---------------------------------------------- - * - * cons_head = br->br_cons_head; - * atomic_cmpset_acq_32(&br->br_prod_head, ...)); - * buf = br->br_ring[cons_head]; > - * br->br_ring[prod_head] = buf; - * atomic_store_rel_32(&br->br_prod_tail, ...); - * prod_tail = br->br_prod_tail; - * if (cons_head == prod_tail) - * return (NULL); - * ` - * - * <1> Load (on core 1) from br->br_ring[cons_head] can be reordered (speculative readed) by CPU. - */ mask = br->br_cons_mask; -#if defined(__arm__) || defined(__aarch64__) - cons_head = atomic_load_acq_32(&br->br_cons_head); -#else cons_head = br->br_cons_head; -#endif prod_tail = atomic_load_acq_32(&br->br_prod_tail); cons_next = cons_head + 1;