From nobody Thu Sep 25 11:51:06 2025 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 4cXX9R10QRz68P4l; Thu, 25 Sep 2025 11:51:07 +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 "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cXX9R0VySz3w6S; Thu, 25 Sep 2025 11:51:07 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758801067; 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=VPqO3uZAk1cEnoabWJns4X+iF9+lKEiPDygksRRFT+w=; b=ZbmCHfOmXX/xJA0kifhPn4++O8l+jl34vHun5edD+ies6W+W/jv3EZ8YA5w1CmsNwjlyKp 7skRCHq1gIs6jQMCrFm8jAkVYi9XJkI+BX8vN3Bpi8UE7Xf4vQ1KHoO58S5agD15O3HPWM 0MxPLJVqfY3iPyKJZSWZOW5RgMuA15JQoELvh4p2Sry8MieJxxlg5NUtCI8aY/6rpcElGp p+jTrzdybIx2PAL9djRLpxYGZUsNTrmJCjeUsWZPMxMnhPzHurSAFSl5MX1JQTtsUUkyQC t6EdVlFktU1YjWnA6daGyx/2Wm7XkcQiUON66gewMRyhudbAskbea8PjmLv1HA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758801067; 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=VPqO3uZAk1cEnoabWJns4X+iF9+lKEiPDygksRRFT+w=; b=XIlA83FXsw0TmfZ1k0g3JePX7QX7uG1vvrMkTDfjkGWPngx/e9v8f0gMd5t4tzxmSkzYZl DOj8xju6PmWzW4u/OD9q+TlExkQ1v3ZmNN7BmRy7rh+AA4Grw8lNTMwuV1IL0yuXlJIdsB 3tlX87iE5Dg2PSvzVzkMsKZRQA4kI5ewSQTq5ggtDxdvBFy4mv54vgoVsp0DOlvzVEckJQ hGyrDf6wbHIcBGVWfYTxKyaj8rt3wIk+6Xd/VebWpPiNizKK4e3p7KOzYjL0jfhmjK2Qd/ LbpuqRT8ZReSzqjgY+E8KI+RDi9jJa8nTZA7g0nFb9H5CfJ4fMrWFAzXK3v7pQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1758801067; a=rsa-sha256; cv=none; b=lN0S+MlSjbm4hk81diybVWw6iWipG//BWlbV/Hv/Dn3/HyWleg11UM+m4avfLEGKJQ4Rv1 xIiph7f/mPgBb+9IqTk+4FCEVybS0FQaYXgX/ekSHiJFDAOlhlZ++2ysVS8ro2IHnXBQlq 8EQwy+ymsfwg8vKLddaTuhi/5NY9slMRQc+lVvzZL+DhWiwvkT9SOZnDy/tiYzBmYcamJm YSkhpOsAg77G/pa3+kKXLqBqz1TTwXa+lqyDMlpGWvTgR22IdF7nz9PlMXhzy7sPyyi1a4 92m1EDkog4bVBP2WhvqPmiCphq/HsnczaIkJLNIntuHRtioyay9wwhdCJI4NrQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none 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 4cXX9R00Hvz1Fr2; Thu, 25 Sep 2025 11:51:06 +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 58PBp67T006610; Thu, 25 Sep 2025 11:51:06 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 58PBp6Qx006607; Thu, 25 Sep 2025 11:51:06 GMT (envelope-from git) Date: Thu, 25 Sep 2025 11:51:06 GMT Message-Id: <202509251151.58PBp6Qx006607@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mateusz Guzik Subject: git: a15f2c5cc58f - main - proc: perform P_CONTROLT check on fork without SESS_LOCK 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: mjg X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: a15f2c5cc58f403407daf797a2e6963adffa6c2c Auto-Submitted: auto-generated The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=a15f2c5cc58f403407daf797a2e6963adffa6c2c commit a15f2c5cc58f403407daf797a2e6963adffa6c2c Author: Mateusz Guzik AuthorDate: 2025-09-25 11:50:01 +0000 Commit: Mateusz Guzik CommitDate: 2025-09-25 11:50:55 +0000 proc: perform P_CONTROLT check on fork without SESS_LOCK The flag is guarded by proc lock which is already held. After tracing poudriere for over 4 hours like so: dtrace -n 'fbt::do_fork:entry { @[curthread->td_proc->p_flag & 0x2] = count(); }': 2 15605151 0 20074116 Over 56% of cases did not have P_CONTROLT set and could have avoided the lock. This reduces hold time of the proctree lock. --- sys/kern/kern_fork.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c index 2ab9b363f8b5..7f6abae187b3 100644 --- a/sys/kern/kern_fork.c +++ b/sys/kern/kern_fork.c @@ -610,10 +610,12 @@ do_fork(struct thread *td, struct fork_req *fr, struct proc *p2, struct thread * p2->p_flag |= p1->p_flag & P_SUGID; td2->td_pflags |= td->td_pflags & (TDP_ALTSTACK | TDP_SIGFASTBLOCK); td2->td_pflags2 |= td->td_pflags2 & TDP2_UEXTERR; - SESS_LOCK(p1->p_session); - if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT) - p2->p_flag |= P_CONTROLT; - SESS_UNLOCK(p1->p_session); + if (p1->p_flag & P_CONTROLT) { + SESS_LOCK(p1->p_session); + if (p1->p_session->s_ttyvp != NULL) + p2->p_flag |= P_CONTROLT; + SESS_UNLOCK(p1->p_session); + } if (fr->fr_flags & RFPPWAIT) p2->p_flag |= P_PPWAIT;