From owner-svn-src-all@freebsd.org Sat Jan 21 06:48:53 2017 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id CC16ACBBB5E; Sat, 21 Jan 2017 06:48:53 +0000 (UTC) (envelope-from jah@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 77AF41C80; Sat, 21 Jan 2017 06:48:53 +0000 (UTC) (envelope-from jah@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v0L6mqkw076451; Sat, 21 Jan 2017 06:48:52 GMT (envelope-from jah@FreeBSD.org) Received: (from jah@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v0L6mqil076450; Sat, 21 Jan 2017 06:48:52 GMT (envelope-from jah@FreeBSD.org) Message-Id: <201701210648.v0L6mqil076450@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: jah set sender to jah@FreeBSD.org using -f From: "Jason A. Harmening" Date: Sat, 21 Jan 2017 06:48:52 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r312561 - stable/11/sys/i386/i386 X-SVN-Group: stable-11 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Jan 2017 06:48:53 -0000 Author: jah Date: Sat Jan 21 06:48:52 2017 New Revision: 312561 URL: https://svnweb.freebsd.org/changeset/base/312561 Log: MFC r312153, r312191 r312153: For i386 temporary mappings, unpin the thread before releasing the cmap lock. Releasing the lock first may result in the thread being immediately rescheduled and bound to the same CPU, only to unpin itself upon resuming execution. Noted by: skra (in review for armv6 equivalent) r312191: Add comment explaining relative order of sched_unpin() and mtx_unlock(). Suggested by: alc Modified: stable/11/sys/i386/i386/pmap.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/i386/i386/pmap.c ============================================================================== --- stable/11/sys/i386/i386/pmap.c Fri Jan 20 22:41:16 2017 (r312560) +++ stable/11/sys/i386/i386/pmap.c Sat Jan 21 06:48:52 2017 (r312561) @@ -4231,8 +4231,14 @@ pmap_zero_page(vm_page_t m) invlcaddr(pc->pc_cmap_addr2); pagezero(pc->pc_cmap_addr2); *cmap_pte2 = 0; - mtx_unlock(&pc->pc_cmap_lock); + + /* + * Unpin the thread before releasing the lock. Otherwise the thread + * could be rescheduled while still bound to the current CPU, only + * to unpin itself immediately upon resuming execution. + */ sched_unpin(); + mtx_unlock(&pc->pc_cmap_lock); } /* @@ -4261,8 +4267,8 @@ pmap_zero_page_area(vm_page_t m, int off else bzero(pc->pc_cmap_addr2 + off, size); *cmap_pte2 = 0; - mtx_unlock(&pc->pc_cmap_lock); sched_unpin(); + mtx_unlock(&pc->pc_cmap_lock); } /* @@ -4316,8 +4322,8 @@ pmap_copy_page(vm_page_t src, vm_page_t bcopy(pc->pc_cmap_addr1, pc->pc_cmap_addr2, PAGE_SIZE); *cmap_pte1 = 0; *cmap_pte2 = 0; - mtx_unlock(&pc->pc_cmap_lock); sched_unpin(); + mtx_unlock(&pc->pc_cmap_lock); } int unmapped_buf_allowed = 1; @@ -4364,8 +4370,8 @@ pmap_copy_pages(vm_page_t ma[], vm_offse } *cmap_pte1 = 0; *cmap_pte2 = 0; - mtx_unlock(&pc->pc_cmap_lock); sched_unpin(); + mtx_unlock(&pc->pc_cmap_lock); } /* @@ -5349,8 +5355,8 @@ pmap_flush_page(vm_page_t m) if (useclflushopt || cpu_vendor_id != CPU_VENDOR_INTEL) mfence(); *cmap_pte2 = 0; - mtx_unlock(&pc->pc_cmap_lock); sched_unpin(); + mtx_unlock(&pc->pc_cmap_lock); } else pmap_invalidate_cache(); }