From nobody Wed Oct 4 12:08:49 2023 X-Original-To: dev-commits-src-all@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 4S0tl54Dvqz4vp1d; Wed, 4 Oct 2023 12:08:49 +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 4S0tl53gPBz3Hlt; Wed, 4 Oct 2023 12:08:49 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1696421329; 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=yAGinDsszOYA/A/pCbmrodbNuLMk/es6iJ/R9qm+TzE=; b=bCTHYHOcLi1vKrmSTh3kykTzrp+FZ0grDuLJeCMEa8R8ch1UxDqxCLK8dtnD5sKuzUEmWL wWwNzYkSFFtn0KSyszWnhGy3wzgEi2Ho/5IJr+HTRrxARYykFb1x8E1AxVI+/+T3NjZbAm TQ55fxTTaWQeEOpiiz/AZQat10Avo+QWkPa8u9EyFul8KdF2j+Uk49cfgz9Pyf6bic6EFi P7XhbscxmREpSQkvC3OMwfCtTzYdlQZ1E3IhY4CxZht1m8UwZm6LR6C/+Z7HO84xudYbB0 XV0t3GDFoAmzo1F0nLBd3gT9sqYTJNG1i6d56uB7PqrINgWZClfRfBmn+rt1GA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1696421329; a=rsa-sha256; cv=none; b=Tt+axftRG0Q7P+W9lozRawo/YEbytpqI6V+YM5oW34/33ZSQo23PjPCgffrAYWa00xuBZM itM13rkuOoh0TnwxRZogH1bvod5THwkwULp/40WFoOVVIQXQIYVe4mjw6CGA7DxAO8TpL1 tLJQZ/eUnMdn7lFDWrWPhYRjEb4pQtRMPFqir4j6SOyuTeswntNpcxzqG77I5ZESAvFCGn 1fJGNOdCw7q8WTm89yqJAgcbMM3VdZJX2usU9n6UuYxSf6c7wStO/rKSUPPRbeuU+3nHpk qAs8QoHkl0gUc0ZzRbwWR6SduECkGQNzfOA3DYXtjBq7ML7sVNgba7bNjHoATw== 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=1696421329; 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=yAGinDsszOYA/A/pCbmrodbNuLMk/es6iJ/R9qm+TzE=; b=Y06OHH/ZTjZ+Shx8ZW/6GFOuVhlNGZC8dwJb3mqYooIemFQgCSU6/q9hdCtQgp+utwDKio 2eJh10wI+xri3dh73leIIZyl/owcTc5HSdsa0Iwv6kSO09bx0TD/aDAFtRcBZKkevLFHUH AZ107PNp7r/YjKJJTZjZKnu+2WPqe1QXJpHnC1879Fn7nLTMEWppzZliZOeXL43bEWDjvX TbjF5V+yaLJpuP09v8wENDYnXPBWHLvcazkdue0s93ec0b0x4XBMuHVZ+JTsFr4YauEi4Z XQfF7lD+LJACXkDW3mpVq5g2/T2GI1xKh8w84TsrpTg6FXaLZ8t+y46NGUyVDg== 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 4S0tl52hd6zcV4; Wed, 4 Oct 2023 12:08:49 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.17.1/8.17.1) with ESMTP id 394C8new053134; Wed, 4 Oct 2023 12:08:49 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.17.1/8.17.1/Submit) id 394C8nbT053131; Wed, 4 Oct 2023 12:08:49 GMT (envelope-from git) Date: Wed, 4 Oct 2023 12:08:49 GMT Message-Id: <202310041208.394C8nbT053131@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mateusz Guzik Subject: git: 21a42a7c22c9 - stable/13 - vfs: drop one vnode list lock trip during vnlru free recycle List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@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/stable/13 X-Git-Reftype: branch X-Git-Commit: 21a42a7c22c9bf921ba9d250c81bd41e70c63ea9 Auto-Submitted: auto-generated The branch stable/13 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=21a42a7c22c9bf921ba9d250c81bd41e70c63ea9 commit 21a42a7c22c9bf921ba9d250c81bd41e70c63ea9 Author: Mateusz Guzik AuthorDate: 2023-09-14 14:35:40 +0000 Commit: Mateusz Guzik CommitDate: 2023-10-04 12:04:15 +0000 vfs: drop one vnode list lock trip during vnlru free recycle vnlru_free_impl would take the lock prior to returning even though most frequent caller does not need it. Unsurprisingly vnode_list mtx is the primary bottleneck when recycling and avoiding the useless lock trip helps. Setting maxvnodes to 400000 and running 20 parallel finds each with a dedicated directory tree of 1 million vnodes in total: before: 4.50s user 1225.71s system 1979% cpu 1:02.14 total after: 4.20s user 806.23s system 1973% cpu 41.059 total That's 34% reduction in total real time. With this the block *remains* the primary bottleneck when running on ZFS. (cherry picked from commit 74be676d87745eb727642f6f8329236c848929d5) --- sys/kern/vfs_subr.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index 209d6ac37cda..40f7a6d33c20 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -1278,13 +1278,14 @@ vnlru_free_impl(int count, struct vfsops *mnt_op, struct vnode *mvp) mtx_assert(&vnode_list_mtx, MA_OWNED); if (count > max_vnlru_free) count = max_vnlru_free; + if (count == 0) { + mtx_unlock(&vnode_list_mtx); + return (0); + } ocount = count; retried = false; vp = mvp; for (;;) { - if (count == 0) { - break; - } vp = TAILQ_NEXT(vp, v_vnodelist); if (__predict_false(vp == NULL)) { /* @@ -1307,6 +1308,7 @@ vnlru_free_impl(int count, struct vfsops *mnt_op, struct vnode *mvp) */ TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist); TAILQ_INSERT_TAIL(&vnode_list, mvp, v_vnodelist); + mtx_unlock(&vnode_list_mtx); break; } if (__predict_false(vp->v_type == VMARKER)) @@ -1354,18 +1356,28 @@ vnlru_free_impl(int count, struct vfsops *mnt_op, struct vnode *mvp) */ vtryrecycle(vp); count--; + if (count == 0) { + break; + } mtx_lock(&vnode_list_mtx); vp = mvp; } + mtx_assert(&vnode_list_mtx, MA_NOTOWNED); return (ocount - count); } +/* + * XXX: returns without vnode_list_mtx locked! + */ static int vnlru_free_locked(int count) { + int ret; mtx_assert(&vnode_list_mtx, MA_OWNED); - return (vnlru_free_impl(count, NULL, vnode_list_free_marker)); + ret = vnlru_free_impl(count, NULL, vnode_list_free_marker); + mtx_assert(&vnode_list_mtx, MA_NOTOWNED); + return (ret); } void @@ -1377,7 +1389,7 @@ vnlru_free_vfsops(int count, struct vfsops *mnt_op, struct vnode *mvp) VNPASS(mvp->v_type == VMARKER, mvp); mtx_lock(&vnode_list_mtx); vnlru_free_impl(count, mnt_op, mvp); - mtx_unlock(&vnode_list_mtx); + mtx_assert(&vnode_list_mtx, MA_NOTOWNED); } /* @@ -1549,7 +1561,7 @@ vnlru_under_unlocked(u_long rnumvnodes, u_long limit) } static void -vnlru_kick(void) +vnlru_kick_locked(void) { mtx_assert(&vnode_list_mtx, MA_OWNED); @@ -1559,6 +1571,15 @@ vnlru_kick(void) } } +static void +vnlru_kick(void) +{ + + mtx_lock(&vnode_list_mtx); + vnlru_kick_locked(); + mtx_unlock(&vnode_list_mtx); +} + static void vnlru_proc(void) { @@ -1589,6 +1610,7 @@ vnlru_proc(void) */ if (rnumvnodes > desiredvnodes) { vnlru_free_locked(rnumvnodes - desiredvnodes); + mtx_lock(&vnode_list_mtx); rnumvnodes = atomic_load_long(&numvnodes); } /* @@ -1767,6 +1789,7 @@ vn_alloc_hard(struct mount *mp) rnumvnodes = atomic_load_long(&numvnodes); if (rnumvnodes + 1 < desiredvnodes) { vn_alloc_cyclecount = 0; + mtx_unlock(&vnode_list_mtx); goto alloc; } rfreevnodes = vnlru_read_freevnodes(); @@ -1786,22 +1809,26 @@ vn_alloc_hard(struct mount *mp) */ if (vnlru_free_locked(1) > 0) goto alloc; + mtx_assert(&vnode_list_mtx, MA_NOTOWNED); if (mp == NULL || (mp->mnt_kern_flag & MNTK_SUSPEND) == 0) { /* * Wait for space for a new vnode. */ - vnlru_kick(); + mtx_lock(&vnode_list_mtx); + vnlru_kick_locked(); vn_alloc_sleeps++; msleep(&vnlruproc_sig, &vnode_list_mtx, PVFS, "vlruwk", hz); if (atomic_load_long(&numvnodes) + 1 > desiredvnodes && vnlru_read_freevnodes() > 1) vnlru_free_locked(1); + else + mtx_unlock(&vnode_list_mtx); } alloc: + mtx_assert(&vnode_list_mtx, MA_NOTOWNED); rnumvnodes = atomic_fetchadd_long(&numvnodes, 1) + 1; if (vnlru_under(rnumvnodes, vlowat)) vnlru_kick(); - mtx_unlock(&vnode_list_mtx); return (uma_zalloc_smr(vnode_zone, M_WAITOK)); }