From owner-dev-commits-src-branches@freebsd.org Tue Aug 31 19:09:49 2021 Return-Path: Delivered-To: dev-commits-src-branches@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id BC957673994; Tue, 31 Aug 2021 19:09:49 +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 "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4GzcFT4CMqz4sl7; Tue, 31 Aug 2021 19:09:49 +0000 (UTC) (envelope-from git@FreeBSD.org) 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 3090A1748C; Tue, 31 Aug 2021 19:09:49 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 17VJ9nhm074272; Tue, 31 Aug 2021 19:09:49 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 17VJ9nMJ074271; Tue, 31 Aug 2021 19:09:49 GMT (envelope-from git) Date: Tue, 31 Aug 2021 19:09:49 GMT Message-Id: <202108311909.17VJ9nMJ074271@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 605e07a27ecb - stable/13 - amd64: a simplication to pmap_remove_{all, write} MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/stable/13 X-Git-Reftype: branch X-Git-Commit: 605e07a27ecb2e32732a0750622f9a960a982071 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-branches@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commits to the stable branches of the FreeBSD src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Aug 2021 19:09:49 -0000 The branch stable/13 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=605e07a27ecb2e32732a0750622f9a960a982071 commit 605e07a27ecb2e32732a0750622f9a960a982071 Author: Alan Cox AuthorDate: 2021-06-30 05:59:21 +0000 Commit: Mark Johnston CommitDate: 2021-08-31 19:09:23 +0000 amd64: a simplication to pmap_remove_{all,write} Eliminate some unnecessary unlocking and relocking when we have to retry the operation to avoid deadlock. (All of the other pmap functions that iterate over a PV list already implemented retries without these same unlocking and relocking operations.) Reviewed by: kib, markj (cherry picked from commit 1a8bcf30f97e6153def2af781db2fe54f5c0d106) --- sys/amd64/amd64/pmap.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index d35422924b1f..16dcddc7786a 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -6192,8 +6192,8 @@ pmap_remove_all(vm_page_t m) lock = VM_PAGE_TO_PV_LIST_LOCK(m); pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : pa_to_pvh(VM_PAGE_TO_PHYS(m)); -retry: rw_wlock(lock); +retry: while ((pv = TAILQ_FIRST(&pvh->pv_list)) != NULL) { pmap = PV_PMAP(pv); if (!PMAP_TRYLOCK(pmap)) { @@ -6202,7 +6202,6 @@ retry: PMAP_LOCK(pmap); rw_wlock(lock); if (pvh_gen != pvh->pv_gen) { - rw_wunlock(lock); PMAP_UNLOCK(pmap); goto retry; } @@ -6221,7 +6220,6 @@ retry: PMAP_LOCK(pmap); rw_wlock(lock); if (pvh_gen != pvh->pv_gen || md_gen != m->md.pv_gen) { - rw_wunlock(lock); PMAP_UNLOCK(pmap); goto retry; } @@ -8348,8 +8346,8 @@ pmap_remove_write(vm_page_t m) lock = VM_PAGE_TO_PV_LIST_LOCK(m); pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : pa_to_pvh(VM_PAGE_TO_PHYS(m)); -retry_pv_loop: rw_wlock(lock); +retry_pv_loop: TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_next, next_pv) { pmap = PV_PMAP(pv); if (!PMAP_TRYLOCK(pmap)) { @@ -8359,7 +8357,6 @@ retry_pv_loop: rw_wlock(lock); if (pvh_gen != pvh->pv_gen) { PMAP_UNLOCK(pmap); - rw_wunlock(lock); goto retry_pv_loop; } } @@ -8384,7 +8381,6 @@ retry_pv_loop: if (pvh_gen != pvh->pv_gen || md_gen != m->md.pv_gen) { PMAP_UNLOCK(pmap); - rw_wunlock(lock); goto retry_pv_loop; } }