diff options
| author | Colin Walters <walters@verbum.org> | 2016-09-01 16:09:30 -0400 |
|---|---|---|
| committer | Atomic Bot <atomic-devel@projectatomic.io> | 2016-09-08 14:56:30 +0000 |
| commit | e127070550fd22d129cd19b45e0d8c74c1b8cc79 (patch) | |
| tree | 7aec868892dd49ca4f8ceeec240ea6467b3b5623 | |
| parent | 8dbb104cdcfaadad8a826eb76fec5f7058c5beb4 (diff) | |
| download | ostree-e127070550fd22d129cd19b45e0d8c74c1b8cc79.tar.gz | |
repo: Only use mmap() for metadata > 16k
See http://stackoverflow.com/questions/258091/when-should-i-use-mmap-for-file-access
and
https://lwn.net/Articles/591978/
I didn't really notice much performance difference in some small
tests, but I happened to be stracing and realized we were `mmap()`ing
even for 50 bytes which is not very useful, so let's not do it.
Closes: #489
Approved by: alexlarsson
| -rw-r--r-- | src/libostree/ostree-repo.c | 56 |
1 files changed, 34 insertions, 22 deletions
diff --git a/src/libostree/ostree-repo.c b/src/libostree/ostree-repo.c index d33a96ab..59bfbf9e 100644 --- a/src/libostree/ostree-repo.c +++ b/src/libostree/ostree-repo.c @@ -2544,6 +2544,7 @@ load_metadata_internal (OstreeRepo *self, { gboolean ret = FALSE; char loose_path_buf[_OSTREE_LOOSE_PATH_MAX]; + struct stat stbuf; glnx_fd_close int fd = -1; g_autoptr(GInputStream) ret_stream = NULL; g_autoptr(GVariant) ret_variant = NULL; @@ -2565,23 +2566,39 @@ load_metadata_internal (OstreeRepo *self, if (fd != -1) { + if (fstat (fd, &stbuf) < 0) + { + glnx_set_error_from_errno (error); + goto out; + } + if (out_variant) { - GMappedFile *mfile; + /* http://stackoverflow.com/questions/258091/when-should-i-use-mmap-for-file-access */ + if (stbuf.st_size > 16*1024) + { + GMappedFile *mfile; - mfile = g_mapped_file_new_from_fd (fd, FALSE, error); - if (!mfile) - goto out; - ret_variant = g_variant_new_from_data (ostree_metadata_variant_type (objtype), - g_mapped_file_get_contents (mfile), - g_mapped_file_get_length (mfile), - TRUE, - (GDestroyNotify) g_mapped_file_unref, - mfile); - g_variant_ref_sink (ret_variant); - - if (out_size) - *out_size = g_variant_get_size (ret_variant); + mfile = g_mapped_file_new_from_fd (fd, FALSE, error); + if (!mfile) + goto out; + ret_variant = g_variant_new_from_data (ostree_metadata_variant_type (objtype), + g_mapped_file_get_contents (mfile), + g_mapped_file_get_length (mfile), + TRUE, + (GDestroyNotify) g_mapped_file_unref, + mfile); + g_variant_ref_sink (ret_variant); + } + else + { + GBytes *data = glnx_fd_readall_bytes (fd, cancellable, error); + if (!data) + goto out; + ret_variant = g_variant_new_from_bytes (ostree_metadata_variant_type (objtype), + data, TRUE); + g_variant_ref_sink (ret_variant); + } } else if (out_stream) { @@ -2589,15 +2606,10 @@ load_metadata_internal (OstreeRepo *self, if (!ret_stream) goto out; fd = -1; /* Transfer ownership */ - if (out_size) - { - struct stat stbuf; - - if (!glnx_stream_fstat ((GFileDescriptorBased*)ret_stream, &stbuf, error)) - goto out; - *out_size = stbuf.st_size; - } } + + if (out_size) + *out_size = stbuf.st_size; } else if (self->parent_repo) { |