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Cached_fs_rom: remove all I/O signal blocking

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Keep things simple, do not block for any signals.
This commit is contained in:
Emery Hemingway 2018-07-12 19:04:57 +02:00 committed by Christian Helmuth
parent 7e08bba25c
commit 0502836975
1 changed files with 33 additions and 47 deletions
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80
repos/os/src/server/cached_fs_rom/main.cc
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@ -45,6 +45,7 @@ namespace Cached_fs_rom {
struct Packet_handler;
struct Main;
typedef File_system::Session::Tx::Source::Packet_alloc_failed Packet_alloc_failed;
}
@ -72,13 +73,29 @@ class Cached_fs_rom::Rom_file final
/**
* Size of file
*/
File_system::file_size_t _file_size = 0;
File_system::file_size_t const _file_size;
/**
* Read offset of file handle
*/
File_system::seek_off_t _file_seek = 0;
/**
* Allocate space in the File_system packet buffer
*
* \throw Packet_alloc_failed
*/
File_system::Packet_descriptor _alloc_packet()
{
size_t chunk_size = min(_file_size, _fs.tx()->bulk_buffer_size()/4);
return _fs.tx()->alloc_packet(chunk_size);
}
/**
* Packet space used by this session
*/
File_system::Packet_descriptor _raw_pkt = _alloc_packet();
/**
* Dataspace to read into
*/
@ -91,11 +108,6 @@ class Cached_fs_rom::Rom_file final
Region_map::Local_addr _rm_attachment { };
Dataspace_capability _rm_ds { };
/**
* Packet space used by this session
*/
File_system::Packet_descriptor _raw_pkt { };
/**
* Reference count of ROM file, initialize to one and
* decrement after read completes.
@ -106,39 +118,12 @@ class Cached_fs_rom::Rom_file final
{
using namespace File_system;
Tx_source &source = *_fs.tx();
while (!source.ready_to_submit()) {
warning("FS packet queue congestion");
_env.ep().wait_and_dispatch_one_io_signal();
}
File_system::Packet_descriptor
packet(_raw_pkt, *_file_handle,
File_system::Packet_descriptor::READ,
_raw_pkt.size(), _file_seek);
source.submit_packet(packet);
}
void _initiate_read()
{
using namespace File_system;
Tx_source &source = *_fs.tx();
size_t chunk_size = min(_file_size, source.bulk_buffer_size()/2);
/* loop until a packet space is allocated */
while (true) {
try { _raw_pkt = source.alloc_packet(chunk_size); break; }
catch (File_system::Session::Tx::Source::Packet_alloc_failed) {
chunk_size = min(_file_size, source.bulk_buffer_size()/4);
_env.ep().wait_and_dispatch_one_io_signal();
}
}
_submit_next_packet();
_fs.tx()->submit_packet(packet);
}
public:
@ -171,7 +156,7 @@ class Cached_fs_rom::Rom_file final
_roms_elem.construct(*this, _roms, Rom_files::Id{~handle.value});
_file_handle.construct(handle);
_initiate_read();
_submit_next_packet();
}
/**
@ -196,9 +181,6 @@ class Cached_fs_rom::Rom_file final
bool unused() const { return (_ref_count < 1); }
bool matches(File_system::Node_handle h) const {
return _file_handle.constructed() ? (*_file_handle == h) : false; }
/**
* Return dataspace with content of file
*/
@ -210,16 +192,9 @@ class Cached_fs_rom::Rom_file final
*/
void process_packet(File_system::Packet_descriptor const packet)
{
if (!(packet.handle() == *_file_handle)) {
error("packet and handle mismatch");
if (packet.position() != _file_seek || _file_seek >= _file_size) {
error("bad packet seek position for ", _file_path, "!");
throw ~0;
}
if (packet.position() > _file_seek || _file_seek >= _file_size) {
error("bad packet seek position");
_file_ds.realloc(&_env.ram(), 0);
_file_seek = 0;
_file_size = 0;
} else {
size_t const n = min(packet.length(), _file_size - _file_seek);
memcpy(_file_ds.local_addr<char>()+_file_seek,
@ -404,6 +379,11 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
});
if (!rom_file) {
if (!fs.tx()->ready_to_submit()) {
Genode::warning("File_system packet queue is congested, defering read of ", path);
return;
}
File_system::File_handle handle = try_open(path);
size_t file_size = fs.status(handle).size;
@ -415,6 +395,11 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
/* session is ready when read completes */
return;
}
catch (Packet_alloc_failed) {
Genode::warning("File_system packet buffer is congested, defering read of ", path);
fs.close(handle);
return;
}
/*
* There is an assumption that failure to allocate
* will implicitly trigger a resource request to the
@ -427,6 +412,7 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
/* eviction failed */
warning("insufficient resources for '", label, "'"
", stalling for upgrade");
fs.close(handle);
return;
}