[PATCH v2] index: add trace2 region for clear skip worktree

From: Anh Le <anh@canva.com>

In a large repository using sparse checkout, checking whether a file marked with skip worktree is present on disk and its skip worktree bit should be cleared can take a considerable amount of time. Add a trace2 region to surface this information, keeping a count of how many paths have been checked and separately keep counts for after a full index is materialised.

Signed-off-by: Anh Le <anh@canva.com>
---
    index: add trace2 region for clear skip worktree
    
    In large repository using sparse checkout, checking whether a file
    marked with skip worktree is present on disk and its skip worktree bit
    should be cleared can take a considerable amount of time. Add a trace2
    region to surface this information.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1368%2FHaizzz%2Fmaster-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1368/Haizzz/master-v2
Pull-Request: https://github.com/git/git/pull/1368

Range-diff vs v1:

 1:  7d1bb3cba2a ! 1:  effe6b5b912 index: add trace2 region for clear skip worktree
     @@ Commit message
          whether a file marked with skip worktree is present
          on disk and its skip worktree bit should be cleared
          can take a considerable amount of time. Add a trace2
     -    region to surface this information.
     +    region to surface this information, keeping a count of how many paths
     +    have been checked and separately
     +    keep counts for after a full index is
     +    materialised.
      
          Signed-off-by: Anh Le <anh@canva.com>
      
     @@ sparse-index.c: void clear_skip_worktree_from_present_files(struct index_state *
       	int dir_found = 1;
       
       	int i;
     -+	intmax_t path_count = 0;
     -+	intmax_t restart_count = 0;
     ++	int path_counts[2] = {0, 0};
     ++	int restarted = 0;
       
       	if (!core_apply_sparse_checkout ||
       	    sparse_expect_files_outside_of_patterns)
     @@ sparse-index.c: void clear_skip_worktree_from_present_files(struct index_state *
      -				ensure_full_index(istate);
      -				goto restart;
      +		if (ce_skip_worktree(ce)) {
     -+			path_count++;
     ++			path_counts[restarted]++;
      +			if (path_found(ce->name, &last_dirname, &dir_len, &dir_found)) {
      +				if (S_ISSPARSEDIR(ce->ce_mode)) {
      +					ensure_full_index(istate);
     -+					restart_count++;
     ++					restarted = 1;
      +					goto restart;
      +				}
      +				ce->ce_flags &= ~CE_SKIP_WORKTREE;
     @@ sparse-index.c: void clear_skip_worktree_from_present_files(struct index_state *
      -			ce->ce_flags &= ~CE_SKIP_WORKTREE;
       		}
       	}
     -+	trace2_data_intmax("index", istate->repo, "clear_skip_worktree_from_present_files/path_count", path_count);
     -+	trace2_data_intmax("index", istate->repo, "clear_skip_worktree_from_present_files/restart_count", restart_count);
     ++
     ++	if (path_counts[0] > 0) {
     ++		trace2_data_intmax("index", istate->repo, "clear_skip_worktree_from_present_files/path_count", path_counts[0]);
     ++	}
     ++	if (restarted) {
     ++		trace2_data_intmax("index", istate->repo, "clear_skip_worktree_from_present_files/full_index/path_count", path_counts[1]);
     ++	}
      +	trace2_region_leave("index", "clear_skip_worktree_from_present_files", istate->repo);
       }
       

 sparse-index.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)