From nobody Sun Mar 27 14:40:52 2022 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 9ED851A46B58; Sun, 27 Mar 2022 14:40:55 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: from mail-lj1-x229.google.com (mail-lj1-x229.google.com [IPv6:2a00:1450:4864:20::229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4KRJRB68kqz4mmT; Sun, 27 Mar 2022 14:40:54 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: by mail-lj1-x229.google.com with SMTP id r22so16042092ljd.4; Sun, 27 Mar 2022 07:40:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=gSy7Du2wDAK0Id/PMfI+tzJfJbLfTJFENoV4Sl3MIKo=; b=bd6emHI3YxUgyi0Kov9unBb6yiCz62DHgdAcI9cA9ovFwD1wWuz/79+sANc6oeGhTx 8sQ1xGUwVVsjO0EFsdkjRyUQ1jyIpl05Lqnpet7cXBLPAFjQtDa/6ViEtmIr+S8IxXtG jbk5MDigStDX18oQzzE/Ocu8LFn38hVLxIJYFI9WEOcuZczSCILaE0e5ma/e2LriA8uf iP8dcnoJm0TV6Q33iLch55heJUpc5DvVQRTO+DD+jsUuuh0mgaDrs8u3KfTewihn06BA zMYKycFwO6GcLyCg3UZ+2A+cAOboC/LSrM6F+IbkbwxK9x+fYcW1aCLOf7TaTK8RiNxN zJhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=gSy7Du2wDAK0Id/PMfI+tzJfJbLfTJFENoV4Sl3MIKo=; b=tDWNIsK9PEJk/jG9l5ESTAyWKqDcEOAFE9anMsyIiNk1xRcCp+dBndZg8yXDbt4cMj oxaBH0UQEGiWHXH+0OIGGQR1a/teqFYBmi/JWru180aLLvAxBBhxg3DKyRc3S70M4IZq f4Vp44h91plkJxiyjOBFTWIQW/OShP79S5H0oD13xvM414HpyFEtPyw/Q0iKULjtgsSE 8LYluT7502Z0upd/P4AK5JGfFTFn74Piha5fbFnmYpSdQpVGS+5bbwChIm0Ov+DRNICW BqZkGV5lHNNq7cw+NfHy4Kuhss2s4YNCQHhF6hqcmO9xiGSeKNhAGlmEFCP9EDIevVHD z77w== X-Gm-Message-State: AOAM531/7YDe6SBc2jAbnp/v48AP90YLCAOMCxDt3p9tPXDzAaQx7sg7 iWyI4KMbLJc4tPgN5I71Hcu75XxjaLTkU10Ws/Qg6aYf X-Google-Smtp-Source: ABdhPJxLV16vQilQGbamndWZ86DiguEH+mKHWiyD3Su41+x3Vy2OFbC6kMjkXK7v39nujZt8UqfMsJmTOPT910ttQc8= X-Received: by 2002:a2e:ba15:0:b0:247:d9d3:a937 with SMTP id p21-20020a2eba15000000b00247d9d3a937mr16066161lja.233.1648392052995; Sun, 27 Mar 2022 07:40:52 -0700 (PDT) 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: Sender: owner-dev-commits-src-main@freebsd.org X-BeenThere: dev-commits-src-main@freebsd.org MIME-Version: 1.0 Received: by 2002:aa6:cb4a:0:b0:1a5:d1a4:cb83 with HTTP; Sun, 27 Mar 2022 07:40:52 -0700 (PDT) In-Reply-To: References: <202203100942.22A9gHMN095945@gitrepo.freebsd.org> From: Mateusz Guzik Date: Sun, 27 Mar 2022 16:40:52 +0200 Message-ID: Subject: Re: git: c35ec1efdcb2 - main - vfs: [1/2] fix stalls in vnode reclaim by not requeieing from vnlru To: Mitchell Horne Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4KRJRB68kqz4mmT X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20210112 header.b=bd6emHI3; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of mjguzik@gmail.com designates 2a00:1450:4864:20::229 as permitted sender) smtp.mailfrom=mjguzik@gmail.com X-Spamd-Result: default: False [-3.98 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-0.996]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20210112]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36:c]; FREEMAIL_FROM(0.00)[gmail.com]; MIME_GOOD(-0.10)[text/plain]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROMTLD(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::229:from]; NEURAL_HAM_SHORT(-0.98)[-0.979]; MLMMJ_DEST(0.00)[dev-commits-src-all,dev-commits-src-main]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim] X-ThisMailContainsUnwantedMimeParts: N Oops. I did make sure the comment is there. :) Interestingly this still would have worked fine enough as most of the problem is worked around by 2/2. Anyhow, fixed. thanks On 3/26/22, Mitchell Horne wrote: > > > On 3/10/22 05:42, Mateusz Guzik wrote: >> The branch main has been updated by mjg: >> >> URL: >> https://cgit.FreeBSD.org/src/commit/?id=c35ec1efdcb2978bc3b6a0098c2b412be8d33e39 >> >> commit c35ec1efdcb2978bc3b6a0098c2b412be8d33e39 >> Author: Mateusz Guzik >> AuthorDate: 2022-03-07 10:33:59 +0000 >> Commit: Mateusz Guzik >> CommitDate: 2022-03-10 09:41:50 +0000 >> >> vfs: [1/2] fix stalls in vnode reclaim by not requeieing from vnlru >> >> Reported by: pho >> --- >> sys/kern/vfs_subr.c | 55 >> +++++++++++++++++++++++++++++++++++++++++++---------- >> 1 file changed, 45 insertions(+), 10 deletions(-) >> >> diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c >> index afafd02d92b9..436323873f7f 100644 >> --- a/sys/kern/vfs_subr.c >> +++ b/sys/kern/vfs_subr.c >> @@ -113,6 +113,8 @@ static void vn_seqc_init(struct vnode *); >> static void vn_seqc_write_end_free(struct vnode *vp); >> static void vgonel(struct vnode *); >> static bool vhold_recycle_free(struct vnode *); >> +static void vdropl_recycle(struct vnode *vp); >> +static void vdrop_recycle(struct vnode *vp); >> static void vfs_knllock(void *arg); >> static void vfs_knlunlock(void *arg); >> static void vfs_knl_assert_lock(void *arg, int what); >> @@ -1207,11 +1209,11 @@ restart: >> mtx_unlock(&vnode_list_mtx); >> >> if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { >> - vdrop(vp); >> + vdrop_recycle(vp); >> goto next_iter_unlocked; >> } >> if (VOP_LOCK(vp, LK_EXCLUSIVE|LK_NOWAIT) != 0) { >> - vdrop(vp); >> + vdrop_recycle(vp); >> vn_finished_write(mp); >> goto next_iter_unlocked; >> } >> @@ -1222,14 +1224,14 @@ restart: >> (vp->v_object != NULL && vp->v_object->handle == vp && >> vp->v_object->resident_page_count > trigger)) { >> VOP_UNLOCK(vp); >> - vdropl(vp); >> + vdropl_recycle(vp); >> vn_finished_write(mp); >> goto next_iter_unlocked; >> } >> counter_u64_add(recycles_count, 1); >> vgonel(vp); >> VOP_UNLOCK(vp); >> - vdropl(vp); >> + vdropl_recycle(vp); >> vn_finished_write(mp); >> done++; >> next_iter_unlocked: >> @@ -1613,7 +1615,7 @@ vtryrecycle(struct vnode *vp) >> CTR2(KTR_VFS, >> "%s: impossible to recycle, vp %p lock is already held", >> __func__, vp); >> - vdrop(vp); >> + vdrop_recycle(vp); >> return (EWOULDBLOCK); >> } >> /* >> @@ -1624,7 +1626,7 @@ vtryrecycle(struct vnode *vp) >> CTR2(KTR_VFS, >> "%s: impossible to recycle, cannot start the write for %p", >> __func__, vp); >> - vdrop(vp); >> + vdrop_recycle(vp); >> return (EBUSY); >> } >> /* >> @@ -1636,7 +1638,7 @@ vtryrecycle(struct vnode *vp) >> VI_LOCK(vp); >> if (vp->v_usecount) { >> VOP_UNLOCK(vp); >> - vdropl(vp); >> + vdropl_recycle(vp); >> vn_finished_write(vnmp); >> CTR2(KTR_VFS, >> "%s: impossible to recycle, %p is already referenced", >> @@ -1648,7 +1650,7 @@ vtryrecycle(struct vnode *vp) >> vgonel(vp); >> } >> VOP_UNLOCK(vp); >> - vdropl(vp); >> + vdropl_recycle(vp); >> vn_finished_write(vnmp); >> return (0); >> } >> @@ -3598,8 +3600,8 @@ vdrop(struct vnode *vp) >> vdropl(vp); >> } >> >> -void >> -vdropl(struct vnode *vp) >> +static void __always_inline >> +vdropl_impl(struct vnode *vp, bool enqueue) >> { > > Hi, > > It seems like enqueue is completely unused within the function. Was > there a hunk missing from the final commit? > > Cheers, > Mitchell > >> >> ASSERT_VI_LOCKED(vp, __func__); >> @@ -3627,6 +3629,39 @@ vdropl(struct vnode *vp) >> vdbatch_enqueue(vp); >> } >> >> +void >> +vdropl(struct vnode *vp) >> +{ >> + >> + vdropl_impl(vp, true); >> +} >> + >> +/* >> + * vdrop a vnode when recycling >> + * >> + * This is a special case routine only to be used when recycling, differs >> from >> + * regular vdrop by not requeieing the vnode on LRU. >> + * >> + * Consider a case where vtryrecycle continuously fails with all vnodes >> (due to >> + * e.g., frozen writes on the filesystem), filling the batch and causing >> it to >> + * be requeued. Then vnlru will end up revisiting the same vnodes. This >> is a >> + * loop which can last for as long as writes are frozen. >> + */ >> +static void >> +vdropl_recycle(struct vnode *vp) >> +{ >> + >> + vdropl_impl(vp, false); >> +} >> + >> +static void >> +vdrop_recycle(struct vnode *vp) >> +{ >> + >> + VI_LOCK(vp); >> + vdropl_recycle(vp); >> +} >> + >> /* >> * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and >> OWEINACT >> * flags. DOINGINACT prevents us from recursing in calls to vinactive. > -- Mateusz Guzik