From patchwork Thu Nov 18 23:13:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Chinner X-Patchwork-Id: 12627945 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE9E6C433EF for ; Thu, 18 Nov 2021 23:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D14C461994 for ; Thu, 18 Nov 2021 23:13:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233069AbhKRXQ5 (ORCPT ); Thu, 18 Nov 2021 18:16:57 -0500 Received: from mail109.syd.optusnet.com.au ([211.29.132.80]:44416 "EHLO mail109.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233025AbhKRXQ5 (ORCPT ); Thu, 18 Nov 2021 18:16:57 -0500 Received: from dread.disaster.area (pa49-195-103-97.pa.nsw.optusnet.com.au [49.195.103.97]) by mail109.syd.optusnet.com.au (Postfix) with ESMTPS id F1367FEB1E1 for ; Fri, 19 Nov 2021 10:13:54 +1100 (AEDT) Received: from discord.disaster.area ([192.168.253.110]) by dread.disaster.area with esmtp (Exim 4.92.3) (envelope-from ) id 1mnqbJ-00AThK-Rf for linux-xfs@vger.kernel.org; Fri, 19 Nov 2021 10:13:53 +1100 Received: from dave by discord.disaster.area with local (Exim 4.95) (envelope-from ) id 1mnqbJ-008bpJ-QV for linux-xfs@vger.kernel.org; Fri, 19 Nov 2021 10:13:53 +1100 From: Dave Chinner To: linux-xfs@vger.kernel.org Subject: [PATCH 08/16] xfs: log ticket region debug is largely useless Date: Fri, 19 Nov 2021 10:13:44 +1100 Message-Id: <20211118231352.2051947-9-david@fromorbit.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211118231352.2051947-1-david@fromorbit.com> References: <20211118231352.2051947-1-david@fromorbit.com> MIME-Version: 1.0 X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=e9dl9Yl/ c=1 sm=1 tr=0 ts=6196de33 a=fP9RlOTWD4uZJjPSFnn6Ew==:117 a=fP9RlOTWD4uZJjPSFnn6Ew==:17 a=vIxV3rELxO4A:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=hXrHYZd4HXSh28dySQwA:9 a=AjGcO6oz07-iQ99wixmX:22 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner xlog_tic_add_region() is used to trace the regions being added to a log ticket to provide information in the situation where a ticket reservation overrun occurs. The information gathered is stored int the ticket, and dumped if xlog_print_tic_res() is called. For a front end struct xfs_trans overrun, the ticket only contains reservation tracking information - the ticket is never handed to the log so has no regions attached to it. The overrun debug information in this case comes from xlog_print_trans(), which walks the items attached to the transaction and dumps their attached formatted log vectors directly. It also dumps the ticket state, but that only contains reservation accounting and nothing else. Hence xlog_print_tic_res() never dumps region or overrun information from this path. xlog_tic_add_region() is actually called from xlog_write(), which means it is being used to track the regions seen in a CIL checkpoint log vector chain. In looking at CIL behaviour recently, I've seen 32MB checkpoints regularly exceed 250,000 regions in the LV chain. The log ticket debug code can track *15* regions. IOWs, if there is a ticket overrun in the CIL code, the ticket region tracking code is going to be completely useless for determining what went wrong. The only thing it can tell us is how much of an overrun occurred, and we really don't need extra debug information in the log ticket to tell us that. Indeed, the main place we call xlog_tic_add_region() is also adding up the number of regions and the space used so that xlog_write() knows how much will be written to the log. This is exactly the same information that log ticket is storing once we take away the useless region tracking array. Hence xlog_tic_add_region() is not useful, but can be called 250,000 times a CIL push... Just strip all that debug "information" out of the of the log ticket and only have it report reservation space information when an overrun occurs. This also reduces the size of a log ticket down by about 150 bytes... Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Reviewed-by: Chandan Babu R --- fs/xfs/xfs_log.c | 107 +++--------------------------------------- fs/xfs/xfs_log_priv.h | 20 -------- 2 files changed, 6 insertions(+), 121 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 0923bee8d4e2..bd2e50804cb4 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -378,30 +378,6 @@ xlog_grant_head_check( return error; } -static void -xlog_tic_reset_res(xlog_ticket_t *tic) -{ - tic->t_res_num = 0; - tic->t_res_arr_sum = 0; - tic->t_res_num_ophdrs = 0; -} - -static void -xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type) -{ - if (tic->t_res_num == XLOG_TIC_LEN_MAX) { - /* add to overflow and start again */ - tic->t_res_o_flow += tic->t_res_arr_sum; - tic->t_res_num = 0; - tic->t_res_arr_sum = 0; - } - - tic->t_res_arr[tic->t_res_num].r_len = len; - tic->t_res_arr[tic->t_res_num].r_type = type; - tic->t_res_arr_sum += len; - tic->t_res_num++; -} - bool xfs_log_writable( struct xfs_mount *mp) @@ -451,8 +427,6 @@ xfs_log_regrant( xlog_grant_push_ail(log, tic->t_unit_res); tic->t_curr_res = tic->t_unit_res; - xlog_tic_reset_res(tic); - if (tic->t_cnt > 0) return 0; @@ -2192,63 +2166,11 @@ xlog_print_tic_res( struct xfs_mount *mp, struct xlog_ticket *ticket) { - uint i; - uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t); - - /* match with XLOG_REG_TYPE_* in xfs_log.h */ -#define REG_TYPE_STR(type, str) [XLOG_REG_TYPE_##type] = str - static char *res_type_str[] = { - REG_TYPE_STR(BFORMAT, "bformat"), - REG_TYPE_STR(BCHUNK, "bchunk"), - REG_TYPE_STR(EFI_FORMAT, "efi_format"), - REG_TYPE_STR(EFD_FORMAT, "efd_format"), - REG_TYPE_STR(IFORMAT, "iformat"), - REG_TYPE_STR(ICORE, "icore"), - REG_TYPE_STR(IEXT, "iext"), - REG_TYPE_STR(IBROOT, "ibroot"), - REG_TYPE_STR(ILOCAL, "ilocal"), - REG_TYPE_STR(IATTR_EXT, "iattr_ext"), - REG_TYPE_STR(IATTR_BROOT, "iattr_broot"), - REG_TYPE_STR(IATTR_LOCAL, "iattr_local"), - REG_TYPE_STR(QFORMAT, "qformat"), - REG_TYPE_STR(DQUOT, "dquot"), - REG_TYPE_STR(QUOTAOFF, "quotaoff"), - REG_TYPE_STR(LRHEADER, "LR header"), - REG_TYPE_STR(UNMOUNT, "unmount"), - REG_TYPE_STR(COMMIT, "commit"), - REG_TYPE_STR(TRANSHDR, "trans header"), - REG_TYPE_STR(ICREATE, "inode create"), - REG_TYPE_STR(RUI_FORMAT, "rui_format"), - REG_TYPE_STR(RUD_FORMAT, "rud_format"), - REG_TYPE_STR(CUI_FORMAT, "cui_format"), - REG_TYPE_STR(CUD_FORMAT, "cud_format"), - REG_TYPE_STR(BUI_FORMAT, "bui_format"), - REG_TYPE_STR(BUD_FORMAT, "bud_format"), - }; - BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1); -#undef REG_TYPE_STR - xfs_warn(mp, "ticket reservation summary:"); - xfs_warn(mp, " unit res = %d bytes", - ticket->t_unit_res); - xfs_warn(mp, " current res = %d bytes", - ticket->t_curr_res); - xfs_warn(mp, " total reg = %u bytes (o/flow = %u bytes)", - ticket->t_res_arr_sum, ticket->t_res_o_flow); - xfs_warn(mp, " ophdrs = %u (ophdr space = %u bytes)", - ticket->t_res_num_ophdrs, ophdr_spc); - xfs_warn(mp, " ophdr + reg = %u bytes", - ticket->t_res_arr_sum + ticket->t_res_o_flow + ophdr_spc); - xfs_warn(mp, " num regions = %u", - ticket->t_res_num); - - for (i = 0; i < ticket->t_res_num; i++) { - uint r_type = ticket->t_res_arr[i].r_type; - xfs_warn(mp, "region[%u]: %s - %u bytes", i, - ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ? - "bad-rtype" : res_type_str[r_type]), - ticket->t_res_arr[i].r_len); - } + xfs_warn(mp, " unit res = %d bytes", ticket->t_unit_res); + xfs_warn(mp, " current res = %d bytes", ticket->t_curr_res); + xfs_warn(mp, " original count = %d", ticket->t_ocnt); + xfs_warn(mp, " remaining count = %d", ticket->t_cnt); } /* @@ -2313,7 +2235,6 @@ xlog_write_calc_vec_length( uint optype) { struct xfs_log_vec *lv; - int headers = 0; int len = 0; int i; @@ -2322,17 +2243,9 @@ xlog_write_calc_vec_length( if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) continue; - headers += lv->lv_niovecs; - - for (i = 0; i < lv->lv_niovecs; i++) { - struct xfs_log_iovec *vecp = &lv->lv_iovecp[i]; - - len += vecp->i_len; - xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type); - } + for (i = 0; i < lv->lv_niovecs; i++) + len += lv->lv_iovecp[i].i_len; } - ticket->t_res_num_ophdrs += headers; - return len; } @@ -2391,7 +2304,6 @@ xlog_write_setup_copy( /* account for new log op header */ ticket->t_curr_res -= sizeof(struct xlog_op_header); - ticket->t_res_num_ophdrs++; return sizeof(struct xlog_op_header); } @@ -3039,9 +2951,6 @@ xlog_state_get_iclog_space( */ if (log_offset == 0) { ticket->t_curr_res -= log->l_iclog_hsize; - xlog_tic_add_region(ticket, - log->l_iclog_hsize, - XLOG_REG_TYPE_LRHEADER); head->h_cycle = cpu_to_be32(log->l_curr_cycle); head->h_lsn = cpu_to_be64( xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block)); @@ -3121,7 +3030,6 @@ xfs_log_ticket_regrant( xlog_grant_sub_space(log, &log->l_write_head.grant, ticket->t_curr_res); ticket->t_curr_res = ticket->t_unit_res; - xlog_tic_reset_res(ticket); trace_xfs_log_ticket_regrant_sub(log, ticket); @@ -3132,7 +3040,6 @@ xfs_log_ticket_regrant( trace_xfs_log_ticket_regrant_exit(log, ticket); ticket->t_curr_res = ticket->t_unit_res; - xlog_tic_reset_res(ticket); } xfs_log_ticket_put(ticket); @@ -3642,8 +3549,6 @@ xlog_ticket_alloc( if (permanent) tic->t_flags |= XLOG_TIC_PERM_RESERV; - xlog_tic_reset_res(tic); - return tic; } diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index 65fb97d596dd..47165c4d2a49 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -142,19 +142,6 @@ enum xlog_iclog_state { #define XLOG_COVER_OPS 5 -/* Ticket reservation region accounting */ -#define XLOG_TIC_LEN_MAX 15 - -/* - * Reservation region - * As would be stored in xfs_log_iovec but without the i_addr which - * we don't care about. - */ -typedef struct xlog_res { - uint r_len; /* region length :4 */ - uint r_type; /* region's transaction type :4 */ -} xlog_res_t; - typedef struct xlog_ticket { struct list_head t_queue; /* reserve/write queue */ struct task_struct *t_task; /* task that owns this ticket */ @@ -165,13 +152,6 @@ typedef struct xlog_ticket { char t_ocnt; /* original count : 1 */ char t_cnt; /* current count : 1 */ char t_flags; /* properties of reservation : 1 */ - - /* reservation array fields */ - uint t_res_num; /* num in array : 4 */ - uint t_res_num_ophdrs; /* num op hdrs : 4 */ - uint t_res_arr_sum; /* array sum : 4 */ - uint t_res_o_flow; /* sum overflow : 4 */ - xlog_res_t t_res_arr[XLOG_TIC_LEN_MAX]; /* array of res : 8 * 15 */ } xlog_ticket_t; /*