From owner-svn-src-head@freebsd.org Wed Aug 26 12:54:18 2020 Return-Path: Delivered-To: svn-src-head@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 B1D7C3D464A; Wed, 26 Aug 2020 12:54:18 +0000 (UTC) (envelope-from mjg@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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Bc5Qy4KHWz3yTF; Wed, 26 Aug 2020 12:54:18 +0000 (UTC) (envelope-from mjg@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 mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 78AC7135DD; Wed, 26 Aug 2020 12:54:18 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 07QCsIEr027945; Wed, 26 Aug 2020 12:54:18 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 07QCsIbx027944; Wed, 26 Aug 2020 12:54:18 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <202008261254.07QCsIbx027944@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Wed, 26 Aug 2020 12:54:18 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r364816 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 364816 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Aug 2020 12:54:18 -0000 Author: mjg Date: Wed Aug 26 12:54:18 2020 New Revision: 364816 URL: https://svnweb.freebsd.org/changeset/base/364816 Log: cache: relock on failure in cache_zap_locked_vnode This gets rid of bogus scheme of yielding in hopes the blocking thread will make progress. Modified: head/sys/kern/vfs_cache.c Modified: head/sys/kern/vfs_cache.c ============================================================================== --- head/sys/kern/vfs_cache.c Wed Aug 26 12:53:16 2020 (r364815) +++ head/sys/kern/vfs_cache.c Wed Aug 26 12:54:18 2020 (r364816) @@ -1134,8 +1134,15 @@ cache_zap_locked_vnode(struct namecache *ncp, struct v to_unlock = vlp2; } else { if (!mtx_trylock(vlp1)) { - error = EAGAIN; - goto out; + /* + * TODO: Very wasteful but rare. + */ + mtx_unlock(pvlp); + mtx_lock(vlp1); + mtx_lock(vlp2); + mtx_unlock(vlp2); + mtx_unlock(vlp1); + return (EAGAIN); } to_unlock = vlp1; } @@ -1377,7 +1384,6 @@ negative_success: error = cache_zap_locked_vnode(ncp, dvp); if (__predict_false(error != 0)) { zap_and_exit_bucket_fail2++; - cache_maybe_yield(); goto retry; } cache_free(ncp); @@ -1465,7 +1471,6 @@ retry: error = cache_zap_locked_bucket(ncp, cnp, hash, blp); if (__predict_false(error != 0)) { zap_and_exit_bucket_fail++; - cache_maybe_yield(); goto retry; } counter_u64_add(numposzaps, 1); @@ -1584,7 +1589,6 @@ negative_success: error = cache_zap_locked_vnode(ncp, dvp); if (__predict_false(error != 0)) { zap_and_exit_bucket_fail2++; - cache_maybe_yield(); goto retry; } cache_free(ncp);