6a7351da0d
a) Fix build if limits.h provides definition for PAGE_SIZE, as musl does w/musl per XSI[1] although it's apparently optional [2]. This value is only provided when it's known to be a constant, to avoid the need to discover the value dynamically. b) If not using system-provided (kernel headers, or libc headers, or something) use the POSIX approach of querying the value dynamically using sysconf(_SC_PAGE_SIZE) instead of hardcoded value that hopefully is correct. [1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html [2] http://www.openwall.com/lists/musl/2015/09/11/8 This patch originate from: https://raw.githubusercontent.com/voidlinux/void-packages/a0ece13ad7ab2aae760e09e41e0459bd999a3695/srcpkgs/thin-provisioning-tools/patches/musl.patch and was also applied in NixOS: https://github.com/NixOS/nixpkgs/pull/40559/ cc @dtzWill
123 lines
2.7 KiB
C++
123 lines
2.7 KiB
C++
#ifndef BLOCK_CACHE_IO_ENGINE_H
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#define BLOCK_CACHE_IO_ENGINE_H
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#include "base/unique_handle.h"
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#include <boost/optional.hpp>
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#include <ctype.h>
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#include <set>
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#include <string>
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#include <libaio.h>
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#include <vector>
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#include <limits.h>
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#ifndef PAGE_SIZE
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#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
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#endif
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//----------------------------------------------------------------
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namespace bcache {
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using sector_t = uint64_t;
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unsigned const SECTOR_SHIFT = 9;
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// Virtual base class to aid unit testing
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class io_engine {
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public:
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enum mode {
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M_READ_ONLY,
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M_READ_WRITE
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};
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enum dir {
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D_READ,
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D_WRITE
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};
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enum sharing {
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EXCLUSIVE,
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SHARED
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};
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io_engine() {}
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virtual ~io_engine() {}
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using handle = unsigned;
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virtual handle open_file(std::string const &path, mode m, sharing s = EXCLUSIVE) = 0;
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virtual void close_file(handle h) = 0;
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// returns false if there are insufficient resources to
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// queue the IO
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virtual bool issue_io(handle h, dir d, sector_t b, sector_t e, void *data, unsigned context) = 0;
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// returns (success, context)
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using wait_result = std::pair<bool, unsigned>;
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virtual boost::optional<wait_result> wait() = 0;
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virtual boost::optional<wait_result> wait(unsigned µsec) = 0;
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private:
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io_engine(io_engine const &) = delete;
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io_engine &operator =(io_engine const &) = delete;
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};
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//--------------------------------
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class control_block_set {
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public:
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control_block_set(unsigned nr);
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iocb *alloc(unsigned context);
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void free(iocb *);
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unsigned context(iocb *) const;
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private:
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struct cblock {
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unsigned context;
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struct iocb cb;
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};
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std::set<unsigned> free_cbs_;
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std::vector<cblock> cbs_;
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};
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//----------------
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class aio_engine : public io_engine {
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public:
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// max_io is the maximum nr of concurrent ios expected
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aio_engine(unsigned max_io);
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~aio_engine();
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using handle = unsigned;
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virtual handle open_file(std::string const &path, mode m, sharing s = EXCLUSIVE);
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virtual void close_file(handle h);
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// Returns false if queueing the io failed
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virtual bool issue_io(handle h, dir d, sector_t b, sector_t e, void *data, unsigned context);
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virtual boost::optional<wait_result> wait();
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virtual boost::optional<wait_result> wait(unsigned µsec);
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private:
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static struct timespec micro_to_ts(unsigned micro);
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static unsigned ts_to_micro(timespec const &ts);
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boost::optional<io_engine::wait_result> wait_(timespec *ts);
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std::list<base::unique_fd> descriptors_;
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io_context_t aio_context_;
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control_block_set cbs_;
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aio_engine(io_engine const &) = delete;
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aio_engine &operator =(io_engine const &) = delete;
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};
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}
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//----------------------------------------------------------------
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#endif
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