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Support for file readahead under linux using readahead #39

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Merged
merged 1 commit into from
Jan 28, 2016
Merged

Support for file readahead under linux using readahead #39

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18 changes: 15 additions & 3 deletions src/io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2066,9 +2066,14 @@ _dispatch_disk_perform(void *ctxt)
static void
_dispatch_operation_advise(dispatch_operation_t op, size_t chunk_size)
{
#ifndef F_RDADVISE
LINUX_PORT_ERROR();
#else
#ifdef __linux__
// linux does not support fcntl (F_RDAVISE)
// define necessary datastructure and use readahead
struct radvisory {
off_t ra_offset;
int ra_count;
};
#endif
int err;
struct radvisory advise;
// No point in issuing a read advise for the next chunk if we are already
Expand All @@ -2088,6 +2093,13 @@ _dispatch_operation_advise(dispatch_operation_t op, size_t chunk_size)
}
advise.ra_offset = op->advise_offset;
op->advise_offset += advise.ra_count;
#ifdef __linux__
_dispatch_io_syscall_switch(err,
readahead(op->fd_entry->fd, advise.ra_offset, advise.ra_count),
case EINVAL: break; // fd does refer to a non-supported filetype
default: (void)dispatch_assume_zero(err); break;
);
#else
_dispatch_io_syscall_switch(err,
fcntl(op->fd_entry->fd, F_RDADVISE, &advise),
case EFBIG: break; // advised past the end of the file rdar://10415691
Expand Down