From b592f75446ccd8fea790de4156478fd057c82019 Mon Sep 17 00:00:00 2001 From: Oleg Drokin Date: Fri, 12 Feb 2021 10:55:42 -0500 Subject: [PATCH] LU-14424 Revert "LU-9679 osc: simplify osc_extent_find()" It looks like there are performance regressions atttributed to this patch. This reverts commit 80e21cce3dd6748fd760786cafe9c26d502fd74f. Change-Id: I55e0abd50573dd82a9d216f9c3b01483f99c3223 Signed-off-by: Oleg Drokin Reviewed-on: https://review.whamcloud.com/41498 Tested-by: jenkins Reviewed-by: Andreas Dilger Reviewed-by: John L. Hammond --- lustre/osc/osc_cache.c | 57 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 42 insertions(+), 15 deletions(-) diff --git a/lustre/osc/osc_cache.c b/lustre/osc/osc_cache.c index 7de0073..9c29955 100644 --- a/lustre/osc/osc_cache.c +++ b/lustre/osc/osc_cache.c @@ -537,14 +537,6 @@ static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur, if (cur->oe_max_end != victim->oe_max_end) return -ERANGE; - /* - * In the rare case max_pages_per_rpc (mppr) is changed, don't - * merge extents until after old ones have been sent, or the - * "extents are aligned to RPCs" checks are unhappy. - */ - if (cur->oe_mppr != victim->oe_mppr) - return -ERANGE; - LASSERT(cur->oe_dlmlock == victim->oe_dlmlock); ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT; chunk_start = cur->oe_start >> ppc_bits; @@ -570,6 +562,7 @@ static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur, cur->oe_urgent |= victim->oe_urgent; cur->oe_memalloc |= victim->oe_memalloc; list_splice_init(&victim->oe_pages, &cur->oe_pages); + list_del_init(&victim->oe_link); victim->oe_nr_pages = 0; osc_extent_get(victim); @@ -697,7 +690,7 @@ static struct osc_extent *osc_extent_find(const struct lu_env *env, cur->oe_start = descr->cld_start; if (cur->oe_end > max_end) cur->oe_end = max_end; - cur->oe_grants = chunksize + cli->cl_grant_extent_tax; + cur->oe_grants = 0; cur->oe_mppr = max_pages; if (olck->ols_dlmlock != NULL) { LASSERT(olck->ols_hold); @@ -765,21 +758,54 @@ restart: * flushed, try next one. */ continue; - if (osc_extent_merge(env, ext, cur) == 0) { + /* check if they belong to the same rpc slot before trying to + * merge. the extents are not overlapped and contiguous at + * chunk level to get here. */ + if (ext->oe_max_end != max_end) + /* if they don't belong to the same RPC slot or + * max_pages_per_rpc has ever changed, do not merge. */ + continue; + + /* check whether maximum extent size will be hit */ + if ((ext_chk_end - ext_chk_start + 1 + 1) << ppc_bits > + cli->cl_max_extent_pages) + continue; + + /* it's required that an extent must be contiguous at chunk + * level so that we know the whole extent is covered by grant + * (the pages in the extent are NOT required to be contiguous). + * Otherwise, it will be too much difficult to know which + * chunks have grants allocated. */ + + /* try to do front merge - extend ext's start */ + if (chunk + 1 == ext_chk_start) { + /* ext must be chunk size aligned */ + EASSERT((ext->oe_start & ~chunk_mask) == 0, ext); + + /* pull ext's start back to cover cur */ + ext->oe_start = cur->oe_start; + ext->oe_grants += chunksize; LASSERT(*grants >= chunksize); *grants -= chunksize; + found = osc_extent_hold(ext); + } else if (chunk == ext_chk_end + 1) { + /* rear merge */ + ext->oe_end = cur->oe_end; + ext->oe_grants += chunksize; + LASSERT(*grants >= chunksize); + *grants -= chunksize; - /* - * Try to merge with the next one too because we - * might have just filled in a gap. - */ + /* try to merge with the next one because we just fill + * in a gap */ if (osc_extent_merge(env, ext, next_extent(ext)) == 0) /* we can save extent tax from next extent */ *grants += cli->cl_grant_extent_tax; - break; + found = osc_extent_hold(ext); } + if (found != NULL) + break; } osc_extent_tree_dump(D_CACHE, obj); @@ -793,6 +819,7 @@ restart: } else if (conflict == NULL) { /* create a new extent */ EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur); + cur->oe_grants = chunksize + cli->cl_grant_extent_tax; LASSERT(*grants >= cur->oe_grants); *grants -= cur->oe_grants; -- 1.8.3.1