GGLinnk/bees
1
0
Fork 0
mirror of https://github.com/Zygo/bees.git synced 2025-07-01 00:02:27 +02:00
Code Packages Activity

context: speed up orderly process termination

Browse Source 
Quite often bees exceeds its service timeout for termination because
it is waiting for a loop embedded in a Task to finish some long-running
btrfs operation.  This can cause bees to be aborted by SIGKILL before
it can completely flush the hash table or save crawl state.

There are only two important things SIGTERM does when bees terminates:
 1.  Save crawl progress
 2.  Flush out the hash table

Everything else is automatically handled by the kernel when the process
is terminated by SIGKILL, so we don't have to bother doing it ourselves.
This can save considerable time at shutdown since we don't have to wait
for every thread to reach a point where it becomes idle, or force loops
to terminate by throwing exceptions, or check a condition every time we
access a pointer.  Instead, we need do only the things in the list
above, and then call _exit() to clean up everything else.

Hash table and crawl state writeback can happen in their background
threads instead of the foreground one.  Separate the "stop" method for
these classes into "stop_request" and "stop_wait" so that these writebacks
can run at the same time.

Deprecate and remove all references to the BeesHalt exception, and remove
several unnecessary checks for BeesContext::stop_requested.

Pause the task queue instead of cancelling it, which preserves the
crawl progress state and stops new Tasks from competing for iops and
CPU during writeback.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
This commit is contained in:
Zygo Blaxell
2022-11-19 02:45:15 -05:00
parent 594ad1786d
commit 31b2aa3c0d
4 changed files with 72 additions and 106 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
src/bees.h
View File

@ -423,7 +423,8 @@ public:
BeesHashTable(shared_ptr<BeesContext> ctx, string filename, off_t size = BLOCK_SIZE_HASHTAB_EXTENT);
~BeesHashTable();
void stop();
void stop_request();
void stop_wait();
vector<Cell> find_cell(HashType hash);
bool push_random_hash_addr(HashType hash, AddrType addr);
@ -595,7 +596,8 @@ friend class BeesTempFile;
public:
BeesRoots(shared_ptr<BeesContext> ctx);
void start();
void stop();
void stop_request();
void stop_wait();
Fd open_root(uint64_t root);
Fd open_root_ino(uint64_t root, uint64_t ino);
@ -720,10 +722,6 @@ struct BeesResolveAddrResult {
bool is_toxic() const { return m_is_toxic; }
};
struct BeesHalt : exception {
const char *what() const noexcept override;
};
class BeesContext : public enable_shared_from_this<BeesContext> {
Fd m_home_fd;
@ -749,10 +747,6 @@ class BeesContext : public enable_shared_from_this<BeesContext> {
bool m_stop_requested = false;
bool m_stop_status = false;
mutable mutex m_abort_mutex;
condition_variable m_abort_condvar;
bool m_abort_requested = false;
shared_ptr<BeesThread> m_progress_thread;
shared_ptr<BeesThread> m_status_thread;