+#include <assert.h>
#include <errno.h>
+#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <functional>
#include <iosfwd>
#include <string>
+#include <sys/stat.h>
#include <unistd.h>
#include <utility>
}
#endif
using_uring = (ret >= 0);
+
+#ifndef WITHOUT_URING
+ if (using_uring) {
+ io_uring_probe *probe = io_uring_get_probe_ring(&ring);
+ supports_stat = (probe != nullptr && io_uring_opcode_supported(probe, IORING_OP_STATX));
+ if (!supports_stat) {
+ dprintf("io_uring on this kernel does not support statx(); will do synchronous access checking.\n");
+ }
+ free(probe);
+ }
+#endif
+}
+
+void IOUringEngine::submit_stat(const char *path, std::function<void()> cb)
+{
+ assert(supports_stat);
+
+#ifndef WITHOUT_URING
+ if (pending_reads < queue_depth) {
+ io_uring_sqe *sqe = io_uring_get_sqe(&ring);
+ if (sqe == nullptr) {
+ fprintf(stderr, "io_uring_get_sqe: %s\n", strerror(errno));
+ exit(1);
+ }
+ submit_stat_internal(sqe, strdup(path), move(cb));
+ } else {
+ QueuedStat qs;
+ qs.cb = move(cb);
+ qs.pathname = strdup(path);
+ queued_stats.push(move(qs));
+ }
+#endif
}
void IOUringEngine::submit_read(int fd, size_t len, off_t offset, function<void(string_view)> cb)
fprintf(stderr, "Couldn't allocate %zu bytes: %s\n", len, strerror(errno));
exit(1);
}
- PendingRead *pending = new PendingRead{ buf, len, move(cb), fd, offset, { buf, len } };
- io_uring_prep_readv(sqe, fd, &pending->iov, 1, offset);
+ PendingRead *pending = new PendingRead;
+ pending->op = OP_READ;
+ pending->read_cb = move(cb);
+ pending->read.buf = buf;
+ pending->read.len = len;
+ pending->read.fd = fd;
+ pending->read.offset = offset;
+ pending->read.iov = iovec{ buf, len };
+
+ io_uring_prep_readv(sqe, fd, &pending->read.iov, 1, offset);
+ io_uring_sqe_set_data(sqe, pending);
+ ++pending_reads;
+}
+
+void IOUringEngine::submit_stat_internal(io_uring_sqe *sqe, char *path, std::function<void()> cb)
+{
+ PendingRead *pending = new PendingRead;
+ pending->op = OP_STAT;
+ pending->stat_cb = move(cb);
+ pending->stat.pathname = path;
+ pending->stat.buf = new struct statx;
+
+ io_uring_prep_statx(sqe, /*fd=*/-1, pending->stat.pathname, AT_STATX_SYNC_AS_STAT, STATX_MODE, pending->stat.buf);
io_uring_sqe_set_data(sqe, pending);
++pending_reads;
}
io_uring_for_each_cqe(&ring, head, cqe)
{
PendingRead *pending = reinterpret_cast<PendingRead *>(cqe->user_data);
- if (cqe->res <= 0) {
- fprintf(stderr, "async read failed: %s\n", strerror(-cqe->res));
- exit(1);
- }
-
- if (size_t(cqe->res) < pending->iov.iov_len) {
- // Incomplete read, so resubmit it.
- pending->iov.iov_base = (char *)pending->iov.iov_base + cqe->res;
- pending->iov.iov_len -= cqe->res;
- pending->offset += cqe->res;
- io_uring_cqe_seen(&ring, cqe);
-
- io_uring_sqe *sqe = io_uring_get_sqe(&ring);
- if (sqe == nullptr) {
- fprintf(stderr, "No free SQE for resubmit; this shouldn't happen.\n");
- exit(1);
- }
- io_uring_prep_readv(sqe, pending->fd, &pending->iov, 1, pending->offset);
- io_uring_sqe_set_data(sqe, pending);
- anything_to_submit = true;
- } else {
+ if (pending->op == OP_STAT) {
io_uring_cqe_seen(&ring, cqe);
--pending_reads;
size_t old_pending_reads = pending_reads;
- pending->cb(string_view(reinterpret_cast<char *>(pending->buf), pending->len));
- free(pending->buf);
+ pending->stat_cb();
+ free(pending->stat.pathname);
+ delete pending->stat.buf;
delete pending;
if (pending_reads != old_pending_reads) {
// so we need to re-submit.
anything_to_submit = true;
}
+ } else {
+ if (cqe->res <= 0) {
+ fprintf(stderr, "async read failed: %s\n", strerror(-cqe->res));
+ exit(1);
+ }
+
+ if (size_t(cqe->res) < pending->read.iov.iov_len) {
+ // Incomplete read, so resubmit it.
+ pending->read.iov.iov_base = (char *)pending->read.iov.iov_base + cqe->res;
+ pending->read.iov.iov_len -= cqe->res;
+ pending->read.offset += cqe->res;
+ io_uring_cqe_seen(&ring, cqe);
+
+ io_uring_sqe *sqe = io_uring_get_sqe(&ring);
+ if (sqe == nullptr) {
+ fprintf(stderr, "No free SQE for resubmit; this shouldn't happen.\n");
+ exit(1);
+ }
+ io_uring_prep_readv(sqe, pending->read.fd, &pending->read.iov, 1, pending->read.offset);
+ io_uring_sqe_set_data(sqe, pending);
+ anything_to_submit = true;
+ } else {
+ io_uring_cqe_seen(&ring, cqe);
+ --pending_reads;
+
+ size_t old_pending_reads = pending_reads;
+ pending->read_cb(string_view(reinterpret_cast<char *>(pending->read.buf), pending->read.len));
+ free(pending->read.buf);
+ delete pending;
+
+ if (pending_reads != old_pending_reads) {
+ // A new read was made in the callback (and not queued),
+ // so we need to re-submit.
+ anything_to_submit = true;
+ }
+ }
+ }
+ }
+
+ // See if there are any queued stats we can submit now.
+ // Running a stat means we're very close to printing out a match,
+ // which is more important than reading more blocks from disk.
+ // (Even if those blocks returned early, they would only generate
+ // more matches that would be blocked by this one in Serializer.)
+ // Thus, prioritize stats.
+ while (!queued_stats.empty() && pending_reads < queue_depth) {
+ io_uring_sqe *sqe = io_uring_get_sqe(&ring);
+ if (sqe == nullptr) {
+ fprintf(stderr, "io_uring_get_sqe: %s\n", strerror(errno));
+ exit(1);
}
+ QueuedStat &qs = queued_stats.front();
+ submit_stat_internal(sqe, qs.pathname, move(qs.cb));
+ queued_stats.pop();
+ anything_to_submit = true;
}
// See if there are any queued reads we can submit now.
#include <iosfwd>
#include <iterator>
#include <limits>
+#include <map>
#include <memory>
#include <queue>
#include <regex.h>
bool patterns_are_regex = false;
bool use_extended_regex = false;
int64_t limit_matches = numeric_limits<int64_t>::max();
+int64_t limit_left = numeric_limits<int64_t>::max();
+
+steady_clock::time_point start;
+
+void apply_limit()
+{
+ if (--limit_left > 0) {
+ return;
+ }
+ dprintf("Done in %.1f ms, found %" PRId64 " matches.\n",
+ 1e3 * duration<float>(steady_clock::now() - start).count(), limit_matches);
+ if (only_count) {
+ printf("%ld\n", limit_matches);
+ }
+ exit(0);
+}
class Serializer {
public:
- bool ready_to_print(int seq) { return next_seq == seq; }
- void print_delayed(int seq, const vector<string> msg);
- void release_current();
+ ~Serializer() { assert(limit_left <= 0 || pending.empty()); }
+ void print(uint64_t seq, uint64_t skip, const string msg);
private:
- int next_seq = 0;
+ uint64_t next_seq = 0;
struct Element {
- int seq;
- vector<string> msg;
+ uint64_t seq, skip;
+ string msg;
bool operator<(const Element &other) const
{
priority_queue<Element> pending;
};
-void Serializer::print_delayed(int seq, const vector<string> msg)
+void Serializer::print(uint64_t seq, uint64_t skip, const string msg)
{
- pending.push(Element{ seq, move(msg) });
-}
+ if (only_count) {
+ if (!msg.empty()) {
+ apply_limit();
+ }
+ return;
+ }
-void Serializer::release_current()
-{
- ++next_seq;
+ if (next_seq != seq) {
+ pending.push(Element{ seq, skip, move(msg) });
+ return;
+ }
+
+ if (!msg.empty()) {
+ if (print_nul) {
+ printf("%s%c", msg.c_str(), 0);
+ } else {
+ printf("%s\n", msg.c_str());
+ }
+ apply_limit();
+ }
+ next_seq += skip;
// See if any delayed prints can now be dealt with.
while (!pending.empty() && pending.top().seq == next_seq) {
- if (limit_matches-- <= 0)
- return;
- for (const string &msg : pending.top().msg) {
+ if (!pending.top().msg.empty()) {
if (print_nul) {
- printf("%s%c", msg.c_str(), 0);
+ printf("%s%c", pending.top().msg.c_str(), 0);
} else {
- printf("%s\n", msg.c_str());
+ printf("%s\n", pending.top().msg.c_str());
}
+ apply_limit();
}
+ next_seq += pending.top().skip;
pending.pop();
- ++next_seq;
}
}
}
}
-bool has_access(const char *filename,
- unordered_map<string, bool> *access_rx_cache)
+class AccessRXCache {
+public:
+ AccessRXCache(IOUringEngine *engine)
+ : engine(engine) {}
+ void check_access(const char *filename, bool allow_async, function<void(bool)> cb);
+
+private:
+ unordered_map<string, bool> cache;
+ struct PendingStat {
+ string filename;
+ function<void(bool)> cb;
+ };
+ map<string, vector<PendingStat>> pending_stats;
+ IOUringEngine *engine;
+};
+
+void AccessRXCache::check_access(const char *filename, bool allow_async, function<void(bool)> cb)
{
- const char *end = strchr(filename + 1, '/');
- while (end != nullptr) {
- string parent_path(filename, end);
- auto it = access_rx_cache->find(parent_path);
- bool ok;
- if (it == access_rx_cache->end()) {
- ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
- access_rx_cache->emplace(move(parent_path), ok);
- } else {
- ok = it->second;
+ if (!engine->get_supports_stat()) {
+ allow_async = false;
+ }
+
+ for (const char *end = strchr(filename + 1, '/'); end != nullptr; end = strchr(end + 1, '/')) {
+ string parent_path(filename, end - filename); // string_view from C++20.
+ auto cache_it = cache.find(parent_path);
+ if (cache_it != cache.end()) {
+ // Found in the cache.
+ if (!cache_it->second) {
+ cb(false);
+ return;
+ }
+ continue;
+ }
+
+ if (!allow_async) {
+ bool ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
+ cache.emplace(parent_path, ok);
+ if (!ok) {
+ cb(false);
+ return;
+ }
+ continue;
}
- if (!ok) {
- return false;
+
+ // We want to call access(), but it could block on I/O. io_uring doesn't support
+ // access(), but we can do a dummy asynchonous statx() to populate the kernel's cache,
+ // which nearly always makes the next access() instantaneous.
+
+ // See if there's already a pending stat that matches this,
+ // or is a subdirectory.
+ auto it = pending_stats.lower_bound(parent_path);
+ if (it != pending_stats.end() && it->first.size() >= parent_path.size() &&
+ it->first.compare(0, parent_path.size(), parent_path) == 0) {
+ it->second.emplace_back(PendingStat{ filename, move(cb) });
+ } else {
+ it = pending_stats.emplace(filename, vector<PendingStat>{}).first;
+ engine->submit_stat(filename, [this, it, filename{ strdup(filename) }, cb{ move(cb) }] {
+ // The stat returned, so now do the actual access() calls.
+ // All of them should be in cache, so don't fire off new statx()
+ // calls during that check.
+ check_access(filename, /*allow_async=*/false, move(cb));
+ free(filename);
+
+ // Call all others that waited for the same stat() to finish.
+ // They may fire off new stat() calls if needed.
+ vector<PendingStat> pending = move(it->second);
+ pending_stats.erase(it);
+ for (PendingStat &ps : pending) {
+ check_access(ps.filename.c_str(), /*allow_async=*/true, move(ps.cb));
+ }
+ });
}
- end = strchr(end + 1, '/');
+ return; // The rest will happen in async context.
}
- return true;
+ // Passed all checks.
+ cb(true);
}
class Corpus {
return hdr.num_docids;
}
-uint64_t scan_file_block(const vector<Needle> &needles, string_view compressed,
- unordered_map<string, bool> *access_rx_cache, int seq,
- Serializer *serializer)
+void scan_file_block(const vector<Needle> &needles, string_view compressed,
+ AccessRXCache *access_rx_cache, uint64_t seq, Serializer *serializer, IOUringEngine *engine,
+ size_t *matched)
{
- uint64_t matched = 0;
-
unsigned long long uncompressed_len = ZSTD_getFrameContentSize(compressed.data(), compressed.size());
if (uncompressed_len == ZSTD_CONTENTSIZE_UNKNOWN || uncompressed_len == ZSTD_CONTENTSIZE_ERROR) {
fprintf(stderr, "ZSTD_getFrameContentSize() failed\n");
}
block[block.size() - 1] = '\0';
- bool immediate_print = (serializer == nullptr || serializer->ready_to_print(seq));
- vector<string> delayed;
+ auto test_candidate = [&](const char *filename, uint64_t local_seq, uint64_t next_seq) {
+ access_rx_cache->check_access(filename, /*allow_async=*/true, [matched, serializer, local_seq, next_seq, filename{ strdup(filename) }](bool ok) {
+ if (ok) {
+ ++*matched;
+ serializer->print(local_seq, next_seq - local_seq, filename);
+ } else {
+ serializer->print(local_seq, next_seq - local_seq, "");
+ }
+ free(filename);
+ });
+ };
+
+ // We need to know the next sequence number before inserting into Serializer,
+ // so always buffer one candidate.
+ const char *pending_candidate = nullptr;
+ uint64_t local_seq = seq << 32;
for (const char *filename = block.data();
filename != block.data() + block.size();
filename += strlen(filename) + 1) {
break;
}
}
- if (found && has_access(filename, access_rx_cache)) {
- if (limit_matches-- <= 0)
- break;
- ++matched;
- if (only_count)
- continue;
- if (immediate_print) {
- if (print_nul) {
- printf("%s%c", filename, 0);
- } else {
- printf("%s\n", filename);
- }
- } else {
- delayed.push_back(filename);
+ if (found) {
+ if (pending_candidate != nullptr) {
+ test_candidate(pending_candidate, local_seq, local_seq + 1);
+ ++local_seq;
}
+ pending_candidate = filename;
}
}
- if (serializer != nullptr && !only_count) {
- if (immediate_print) {
- serializer->release_current();
- } else {
- serializer->print_delayed(seq, move(delayed));
- }
+ if (pending_candidate == nullptr) {
+ serializer->print(seq << 32, 1ULL << 32, "");
+ } else {
+ test_candidate(pending_candidate, local_seq, (seq + 1) << 32);
}
- return matched;
}
size_t scan_docids(const vector<Needle> &needles, const vector<uint32_t> &docids, const Corpus &corpus, IOUringEngine *engine)
{
Serializer docids_in_order;
- unordered_map<string, bool> access_rx_cache;
+ AccessRXCache access_rx_cache(engine);
uint64_t matched = 0;
for (size_t i = 0; i < docids.size(); ++i) {
uint32_t docid = docids[i];
- corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, &docids_in_order](string_view compressed) {
- matched += scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order);
+ corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, engine, &docids_in_order](string_view compressed) {
+ scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order, engine, &matched);
});
}
engine->finish();
// coalesce it plus readahead for us.
uint64_t scan_all_docids(const vector<Needle> &needles, int fd, const Corpus &corpus, IOUringEngine *engine)
{
- unordered_map<string, bool> access_rx_cache;
+ AccessRXCache access_rx_cache(engine);
uint32_t num_blocks = corpus.get_num_filename_blocks();
unique_ptr<uint64_t[]> offsets(new uint64_t[num_blocks + 1]);
complete_pread(fd, offsets.get(), (num_blocks + 1) * sizeof(uint64_t), corpus.offset_for_block(0));
for (uint32_t docid = io_docid; docid < last_docid; ++docid) {
size_t relative_offset = offsets[docid] - offsets[io_docid];
size_t len = offsets[docid + 1] - offsets[docid];
- matched += scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, 0, nullptr);
- if (limit_matches <= 0)
- return matched;
+ scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, 0, nullptr, engine, &matched);
}
}
return matched;
exit(EXIT_FAILURE);
}
- steady_clock::time_point start __attribute__((unused)) = steady_clock::now();
+ start = steady_clock::now();
if (access("/", R_OK | X_OK)) {
// We can't find anything, no need to bother...
return;
break;
case 'l':
case 'n':
- limit_matches = atoll(optarg);
+ limit_matches = limit_left = atoll(optarg);
if (limit_matches <= 0) {
fprintf(stderr, "Error: limit must be a strictly positive number.\n");
exit(1);
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