From patchwork Thu Nov 18 23:13:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Chinner X-Patchwork-Id: 12628015 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 CBAE5C433F5 for ; Thu, 18 Nov 2021 23:31:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A59C861A86 for ; Thu, 18 Nov 2021 23:31:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233117AbhKRXeP (ORCPT ); Thu, 18 Nov 2021 18:34:15 -0500 Received: from mail109.syd.optusnet.com.au ([211.29.132.80]:39658 "EHLO mail109.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231958AbhKRXeP (ORCPT ); Thu, 18 Nov 2021 18:34:15 -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 89294FEB530 for ; Fri, 19 Nov 2021 10:31:13 +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-00AThI-Qg 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-008bpE-PA 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 07/16] xfs: reserve space and initialise xlog_op_header in item formatting Date: Fri, 19 Nov 2021 10:13:43 +1100 Message-Id: <20211118231352.2051947-8-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=epq8cqlX c=1 sm=1 tr=0 ts=6196e241 a=fP9RlOTWD4uZJjPSFnn6Ew==:117 a=fP9RlOTWD4uZJjPSFnn6Ew==:17 a=vIxV3rELxO4A:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=hH36q76zEQHc0ou5sH0A:9 a=AjGcO6oz07-iQ99wixmX:22 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner Current xlog_write() adds op headers to the log manually for every log item region that is in the vector passed to it. While xlog_write() needs to stamp the transaction ID into the ophdr, we already know it's length, flags, clientid, etc at CIL commit time. This means the only time that xlog write really needs to format and reserve space for a new ophdr is when a region is split across two iclogs. Adding the opheader and accounting for it as part of the normal formatted item region means we simplify the accounting of space used by a transaction and we don't have to special case reserving of space in for the ophdrs in xlog_write(). It also means we can largely initialise the ophdr in transaction commit instead of xlog_write, making the xlog_write formatting inner loop much tighter. xlog_prepare_iovec() is now too large to stay as an inline function, so we move it out of line and into xfs_log.c. Object sizes: text data bss dec hex filename 1125934 305951 484 1432369 15db31 fs/xfs/built-in.a.before 1123360 305951 484 1429795 15d123 fs/xfs/built-in.a.after So the code is a roughly 2.5kB smaller with xlog_prepare_iovec() now out of line, even though it grew in size itself. Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Chandan Babu R --- fs/xfs/xfs_log.c | 115 +++++++++++++++++++++++++++++-------------- fs/xfs/xfs_log.h | 42 +++------------- fs/xfs/xfs_log_cil.c | 25 +++++----- 3 files changed, 99 insertions(+), 83 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index f09663d3664b..0923bee8d4e2 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -90,6 +90,62 @@ xlog_iclogs_empty( static int xfs_log_cover(struct xfs_mount *); +/* + * We need to make sure the buffer pointer returned is naturally aligned for the + * biggest basic data type we put into it. We have already accounted for this + * padding when sizing the buffer. + * + * However, this padding does not get written into the log, and hence we have to + * track the space used by the log vectors separately to prevent log space hangs + * due to inaccurate accounting (i.e. a leak) of the used log space through the + * CIL context ticket. + * + * We also add space for the xlog_op_header that describes this region in the + * log. This prepends the data region we return to the caller to copy their data + * into, so do all the static initialisation of the ophdr now. Because the ophdr + * is not 8 byte aligned, we have to be careful to ensure that we align the + * start of the buffer such that the region we return to the call is 8 byte + * aligned and packed against the tail of the ophdr. + */ +void * +xlog_prepare_iovec( + struct xfs_log_vec *lv, + struct xfs_log_iovec **vecp, + uint type) +{ + struct xfs_log_iovec *vec = *vecp; + struct xlog_op_header *oph; + uint32_t len; + void *buf; + + if (vec) { + ASSERT(vec - lv->lv_iovecp < lv->lv_niovecs); + vec++; + } else { + vec = &lv->lv_iovecp[0]; + } + + len = lv->lv_buf_len + sizeof(struct xlog_op_header); + if (!IS_ALIGNED(len, sizeof(uint64_t))) { + lv->lv_buf_len = round_up(len, sizeof(uint64_t)) - + sizeof(struct xlog_op_header); + } + + vec->i_type = type; + vec->i_addr = lv->lv_buf + lv->lv_buf_len; + + oph = vec->i_addr; + oph->oh_clientid = XFS_TRANSACTION; + oph->oh_res2 = 0; + oph->oh_flags = 0; + + buf = vec->i_addr + sizeof(struct xlog_op_header); + ASSERT(IS_ALIGNED((unsigned long)buf, sizeof(uint64_t))); + + *vecp = vec; + return buf; +} + static void xlog_grant_sub_space( struct xlog *log, @@ -2246,9 +2302,9 @@ xlog_print_trans( } /* - * Calculate the potential space needed by the log vector. If this is a start - * transaction, the caller has already accounted for both opheaders in the start - * transaction, so we don't need to account for them here. + * Calculate the potential space needed by the log vector. All regions contain + * their own opheaders and they are accounted for in region space so we don't + * need to add them to the vector length here. */ static int xlog_write_calc_vec_length( @@ -2275,18 +2331,7 @@ xlog_write_calc_vec_length( xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type); } } - - /* Don't account for regions with embedded ophdrs */ - if (optype && headers > 0) { - headers--; - if (optype & XLOG_START_TRANS) { - ASSERT(headers >= 1); - headers--; - } - } - ticket->t_res_num_ophdrs += headers; - len += headers * sizeof(struct xlog_op_header); return len; } @@ -2296,7 +2341,6 @@ xlog_write_setup_ophdr( struct xlog_op_header *ophdr, struct xlog_ticket *ticket) { - ophdr->oh_tid = cpu_to_be32(ticket->t_tid); ophdr->oh_clientid = XFS_TRANSACTION; ophdr->oh_res2 = 0; ophdr->oh_flags = 0; @@ -2514,21 +2558,25 @@ xlog_write( ASSERT((unsigned long)ptr % sizeof(int32_t) == 0); /* - * The XLOG_START_TRANS has embedded ophdrs for the - * start record and transaction header. They will always - * be the first two regions in the lv chain. Commit and - * unmount records also have embedded ophdrs. + * Regions always have their ophdr at the start of the + * region, except for: + * - a transaction start which has a start record ophdr + * before the first region ophdr; and + * - the previous region didn't fully fit into an iclog + * so needs a continuation ophdr to prepend the region + * in this new iclog. */ - if (optype) { - ophdr = reg->i_addr; - if (index) - optype &= ~XLOG_START_TRANS; - } else { + ophdr = reg->i_addr; + if (optype && index) { + optype &= ~XLOG_START_TRANS; + } else if (partial_copy) { ophdr = xlog_write_setup_ophdr(ptr, ticket); xlog_write_adv_cnt(&ptr, &len, &log_offset, sizeof(struct xlog_op_header)); added_ophdr = true; } + ophdr->oh_tid = cpu_to_be32(ticket->t_tid); + len += xlog_write_setup_copy(ticket, ophdr, iclog->ic_size-log_offset, reg->i_len, @@ -2546,20 +2594,11 @@ xlog_write( ophdr->oh_len = cpu_to_be32(copy_len - sizeof(struct xlog_op_header)); } - /* - * Copy region. - * - * Commit records just log an opheader, so - * we can have empty payloads with no data region to - * copy. Hence we only copy the payload if the vector - * says it has data to copy. - */ - ASSERT(copy_len >= 0); - if (copy_len > 0) { - memcpy(ptr, reg->i_addr + copy_off, copy_len); - xlog_write_adv_cnt(&ptr, &len, &log_offset, - copy_len); - } + + ASSERT(copy_len > 0); + memcpy(ptr, reg->i_addr + copy_off, copy_len); + xlog_write_adv_cnt(&ptr, &len, &log_offset, copy_len); + if (added_ophdr) copy_len += sizeof(struct xlog_op_header); record_cnt++; diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h index d1fc43476166..816f44d7dc81 100644 --- a/fs/xfs/xfs_log.h +++ b/fs/xfs/xfs_log.h @@ -21,44 +21,18 @@ struct xfs_log_vec { #define XFS_LOG_VEC_ORDERED (-1) -/* - * We need to make sure the buffer pointer returned is naturally aligned for the - * biggest basic data type we put into it. We have already accounted for this - * padding when sizing the buffer. - * - * However, this padding does not get written into the log, and hence we have to - * track the space used by the log vectors separately to prevent log space hangs - * due to inaccurate accounting (i.e. a leak) of the used log space through the - * CIL context ticket. - */ -static inline void * -xlog_prepare_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp, - uint type) -{ - struct xfs_log_iovec *vec = *vecp; - - if (vec) { - ASSERT(vec - lv->lv_iovecp < lv->lv_niovecs); - vec++; - } else { - vec = &lv->lv_iovecp[0]; - } - - if (!IS_ALIGNED(lv->lv_buf_len, sizeof(uint64_t))) - lv->lv_buf_len = round_up(lv->lv_buf_len, sizeof(uint64_t)); - - vec->i_type = type; - vec->i_addr = lv->lv_buf + lv->lv_buf_len; - - ASSERT(IS_ALIGNED((unsigned long)vec->i_addr, sizeof(uint64_t))); - - *vecp = vec; - return vec->i_addr; -} +void *xlog_prepare_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp, + uint type); static inline void xlog_finish_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec *vec, int len) { + struct xlog_op_header *oph = vec->i_addr; + + /* opheader tracks payload length, logvec tracks region length */ + oph->oh_len = cpu_to_be32(len); + + len += sizeof(struct xlog_op_header); lv->lv_buf_len += len; lv->lv_bytes += len; vec->i_len = len; diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index 29cf2d5d0b96..90a0e9b9d3e0 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -181,13 +181,20 @@ xlog_cil_alloc_shadow_bufs( } /* - * We 64-bit align the length of each iovec so that the start - * of the next one is naturally aligned. We'll need to - * account for that slack space here. Then round nbytes up - * to 64-bit alignment so that the initial buffer alignment is - * easy to calculate and verify. + * We 64-bit align the length of each iovec so that the start of + * the next one is naturally aligned. We'll need to account for + * that slack space here. + * + * We also add the xlog_op_header to each region when + * formatting, but that's not accounted to the size of the item + * at this point. Hence we'll need an addition number of bytes + * for each vector to hold an opheader. + * + * Then round nbytes up to 64-bit alignment so that the initial + * buffer alignment is easy to calculate and verify. */ - nbytes += niovecs * sizeof(uint64_t); + nbytes += niovecs * + (sizeof(uint64_t) + sizeof(struct xlog_op_header)); nbytes = round_up(nbytes, sizeof(uint64_t)); /* @@ -441,11 +448,6 @@ xlog_cil_insert_items( spin_lock(&cil->xc_cil_lock); - /* account for space used by new iovec headers */ - iovhdr_res = diff_iovecs * sizeof(xlog_op_header_t); - len += iovhdr_res; - ctx->nvecs += diff_iovecs; - /* attach the transaction to the CIL if it has any busy extents */ if (!list_empty(&tp->t_busy)) list_splice_init(&tp->t_busy, &ctx->busy_extents); @@ -477,6 +479,7 @@ xlog_cil_insert_items( } tp->t_ticket->t_curr_res -= len; ctx->space_used += len; + ctx->nvecs += diff_iovecs; /* * If we've overrun the reservation, dump the tx details before we move