On Wed, Mar 17, 2021 at 10:12 PM Matheus Tavares
<matheus.bernardino@xxxxxx> wrote:
> diff --git a/.gitignore b/.gitignore
> index 3dcdb6bb5a..26f8ddfc55 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -33,6 +33,7 @@
> /git-check-mailmap
> /git-check-ref-format
> /git-checkout
> +/git-checkout--helper
I wonder if "checkout--worker" would be better than "checkout--helper".
> /git-checkout-index
> /git-cherry
> /git-cherry-pick
[...]
> +#define ASSERT_PC_ITEM_RESULT_SIZE(got, exp) \
> +{ \
> + if (got != exp) \
> + BUG("corrupted result from checkout worker (got %dB, exp %dB)", \
Maybe precompilers are smart enough to not replace the "got" and "exp"
in the above string, but it might be a bit confusing for readers.
Anway I wonder if this macro could just be a regular (possibly inline)
function.
> + got, exp); \
> +} while(0)
> +static void parse_and_save_result(const char *line, int len,
> + struct pc_worker *worker)
> +{
> + struct pc_item_result *res;
> + struct parallel_checkout_item *pc_item;
> + struct stat *st = NULL;
> +
> + if (len < PC_ITEM_RESULT_BASE_SIZE)
> + BUG("too short result from checkout worker (got %dB, exp %dB)",
> + len, (int)PC_ITEM_RESULT_BASE_SIZE);
> +
> + res = (struct pc_item_result *)line;
> +
> + /*
> + * Worker should send either the full result struct on success, or
> + * just the base (i.e. no stat data), otherwise.
> + */
> + if (res->status == PC_ITEM_WRITTEN) {
> + ASSERT_PC_ITEM_RESULT_SIZE(len, (int)sizeof(struct pc_item_result));
> + st = &res->st;
> + } else {
> + ASSERT_PC_ITEM_RESULT_SIZE(len, (int)PC_ITEM_RESULT_BASE_SIZE);
> + }
> +
> + if (!worker->nr_items_to_complete || res->id != worker->next_item_to_complete)
Nit: maybe it could be useful to distinguish between these 2 potential
bugs and have a specific BUG() for each one.
> + BUG("checkout worker sent unexpected item id");
> + worker->next_item_to_complete++;
> + worker->nr_items_to_complete--;
> +
> + pc_item = ¶llel_checkout.items[res->id];
> + pc_item->status = res->status;
> + if (st)
> + pc_item->st = *st;
> +}
> +
> +
One blank line is enough.
> +static void gather_results_from_workers(struct pc_worker *workers,
> + int num_workers)
> +{
> + int i, active_workers = num_workers;
> + struct pollfd *pfds;
> +
> + CALLOC_ARRAY(pfds, num_workers);
> + for (i = 0; i < num_workers; i++) {
> + pfds[i].fd = workers[i].cp.out;
> + pfds[i].events = POLLIN;
> + }
> +
> + while (active_workers) {
> + int nr = poll(pfds, num_workers, -1);
> +
> + if (nr < 0) {
> + if (errno == EINTR)
> + continue;
> + die_errno("failed to poll checkout workers");
> + }
> +
> + for (i = 0; i < num_workers && nr > 0; i++) {
Is it possible that nr is 0? If that happens, it looks like we would
be in an infinite `while (active_workers) { ... }` loop.
Actually in poll(2) there is: "A value of 0 indicates that the call
timed out and no file descriptors were ready." So it seems that it
could, at least theorically, happen.
> + struct pc_worker *worker = &workers[i];
> + struct pollfd *pfd = &pfds[i];
> +
> + if (!pfd->revents)
> + continue;
> +
> + if (pfd->revents & POLLIN) {
> + int len;
> + const char *line = packet_read_line(pfd->fd, &len);
> +
> + if (!line) {
> + pfd->fd = -1;
> + active_workers--;
> + } else {
> + parse_and_save_result(line, len, worker);
> + }
> + } else if (pfd->revents & POLLHUP) {
> + pfd->fd = -1;
> + active_workers--;
> + } else if (pfd->revents & (POLLNVAL | POLLERR)) {
> + die(_("error polling from checkout worker"));
> + }
> +
> + nr--;
> + }
> + }
> +
> + free(pfds);
> +}
[...]
> +enum pc_item_status {
> + PC_ITEM_PENDING = 0,
> + PC_ITEM_WRITTEN,
> + /*
> + * The entry could not be written because there was another file
> + * already present in its path or leading directories. Since
> + * checkout_entry_ca() removes such files from the working tree before
> + * enqueueing the entry for parallel checkout, it means that there was
> + * a path collision among the entries being written.
> + */
> + PC_ITEM_COLLIDED,
> + PC_ITEM_FAILED,
> +};
> +
> +struct parallel_checkout_item {
> + /*
> + * In main process ce points to a istate->cache[] entry. Thus, it's not
> + * owned by us. In workers they own the memory, which *must be* released.
> + */
> + struct cache_entry *ce;
> + struct conv_attrs ca;
> + size_t id; /* position in parallel_checkout.items[] of main process */
> +
> + /* Output fields, sent from workers. */
> + enum pc_item_status status;
> + struct stat st;
> +};
Maybe the previous patch could have declared both 'enum
pc_item_status' and 'struct parallel_checkout_item' here, in
parallel-checkout.h, so that this patch wouldn't need to move them
here.
