From 96045cbe9a089897107decefa9ff97d0d3b2810e Mon Sep 17 00:00:00 2001 From: root Date: Mon, 18 Jul 2011 02:59:58 +0000 Subject: *** empty log message *** --- eio.c | 43 ++++++++++++++----------------------------- eio.pod | 36 +++++++++++++++++++++--------------- 2 files changed, 35 insertions(+), 44 deletions(-) diff --git a/eio.c b/eio.c index b367868..063e50a 100644 --- a/eio.c +++ b/eio.c @@ -235,13 +235,13 @@ static void eio_destroy (eio_req *req); #define EIO_BUFSIZE 65536 #define dBUF \ - char *eio_buf; \ - ETP_WORKER_LOCK (self); \ - self->dbuf = eio_buf = malloc (EIO_BUFSIZE); \ - ETP_WORKER_UNLOCK (self); \ + char *eio_buf = malloc (EIO_BUFSIZE); \ errno = ENOMEM; \ if (!eio_buf) \ - return -1; + return -1 + +#define FUBd \ + free (eio_buf) #define EIO_TICKS ((1000000 + 1023) >> 10) @@ -257,16 +257,6 @@ static int eio_finish (eio_req *req); static void eio_execute (struct etp_worker *self, eio_req *req); #define ETP_EXECUTE(wrk,req) eio_execute (wrk,req) -#define ETP_WORKER_CLEAR(req) \ - if (wrk->dbuf) \ - { \ - free (wrk->dbuf); \ - wrk->dbuf = 0; \ - } - -#define ETP_WORKER_COMMON \ - void *dbuf; - /*****************************************************************************/ #define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1) @@ -317,7 +307,9 @@ typedef struct etp_worker /* locked by reslock, reqlock or wrklock */ ETP_REQ *req; /* currently processed request */ +#ifdef ETP_WORKER_COMMON ETP_WORKER_COMMON +#endif } etp_worker; static etp_worker wrk_first; /* NOT etp */ @@ -330,7 +322,6 @@ static etp_worker wrk_first; /* NOT etp */ static void ecb_cold etp_worker_clear (etp_worker *wrk) { - ETP_WORKER_CLEAR (wrk); } static void ecb_cold @@ -999,6 +990,8 @@ eio__readahead (int fd, off_t offset, size_t count, etp_worker *self) todo -= len; } + FUBd; + errno = 0; return count; } @@ -1007,7 +1000,7 @@ eio__readahead (int fd, off_t offset, size_t count, etp_worker *self) /* sendfile always needs emulation */ static eio_ssize_t -eio__sendfile (int ofd, int ifd, off_t offset, size_t count, etp_worker *self) +eio__sendfile (int ofd, int ifd, off_t offset, size_t count) { eio_ssize_t written = 0; eio_ssize_t res; @@ -1153,6 +1146,8 @@ eio__sendfile (int ofd, int ifd, off_t offset, size_t count, etp_worker *self) res += cnt; count -= cnt; } + + FUBd; } return res; @@ -2027,7 +2022,7 @@ eio_execute (etp_worker *self, eio_req *req) : write (req->int1, req->ptr2, req->size); break; case EIO_READAHEAD: req->result = readahead (req->int1, req->offs, req->size); break; - case EIO_SENDFILE: req->result = eio__sendfile (req->int1, req->int2, req->offs, req->size, self); break; + case EIO_SENDFILE: req->result = eio__sendfile (req->int1, req->int2, req->offs, req->size); break; case EIO_STAT: ALLOC (sizeof (EIO_STRUCT_STAT)); req->result = stat (req->ptr1, (EIO_STRUCT_STAT *)req->ptr2); break; @@ -2427,16 +2422,6 @@ eio_grp_add (eio_req *grp, eio_req *req) eio_ssize_t eio_sendfile_sync (int ofd, int ifd, off_t offset, size_t count) { - etp_worker wrk; - eio_ssize_t ret; - - wrk.dbuf = 0; - - ret = eio__sendfile (ofd, ifd, offset, count, &wrk); - - if (wrk.dbuf) - free (wrk.dbuf); - - return ret; + return eio__sendfile (ofd, ifd, offset, count); } diff --git a/eio.pod b/eio.pod index a2ccf24..5c81d4b 100644 --- a/eio.pod +++ b/eio.pod @@ -47,21 +47,24 @@ time differences throughout libeio. =head2 FORK SUPPORT -Calling C is fully supported by this module - but you must not -rely on this. It is currently implemented in these steps: - - 1. wait till all requests in "execute" state have been handled - (basically requests that are already handed over to the kernel). - 2. fork - 3. in the parent, continue business as usual, done - 4. in the child, destroy all ready and pending requests and free the - memory used by the worker threads. This gives you a fully empty - libeio queue. - -Note, however, since libeio does use threads, the above guarantee doesn't -cover your libc, for example, malloc and other libc functions are not -fork-safe, so there is very little you can do after a fork, and in fact, -the above might crash, and thus change. +Usage of pthreads in a program changes the semantics of fork +considerably. Specifically, only async-safe functions can be called after +fork. Libeio uses pthreads, so this applies, and makes using fork hard for +anything but relatively fork + exec uses. + +This library only works in the process that initialised it: Forking is +fully supported, but using libeio in any other process than the one that +called C is not. + +You might get around by not I libeio before (or after) forking in +the parent, and using it in the child afterwards. You could also try to +call the L function again in the child, which will brutally +reinitialise all data structures, which isn't POSIX conformant, but +typically works. + +Otherwise, the only recommendation you should follow is: treat fork code +the same way you treat signal handlers, and only ever call C in +the process that uses it, and only once ever. =head1 INITIALISATION/INTEGRATION @@ -81,6 +84,9 @@ failure it returns C<-1> and sets C appropriately. It accepts two function pointers specifying callbacks as argument, both of which can be C<0>, in which case the callback isn't called. +There is currently no way to change these callbacks later, or to +"uninitialise" the library again. + =item want_poll callback The C callback is invoked whenever libeio wants attention (i.e. -- cgit v1.2.3