diff options
| -rw-r--r-- | lib/libc/sys/sendfile.2 | 123 | ||||
| -rw-r--r-- | sys/dev/ti/if_ti.c | 4 | ||||
| -rw-r--r-- | sys/kern/uipc_mbuf.c | 4 | ||||
| -rw-r--r-- | sys/kern/uipc_syscalls.c | 682 | ||||
| -rw-r--r-- | sys/sys/mbuf.h | 4 | ||||
| -rw-r--r-- | sys/sys/sf_buf.h | 7 | ||||
| -rw-r--r-- | sys/sys/socket.h | 5 | ||||
| -rw-r--r-- | usr.bin/netstat/mbuf.c | 26 |
8 files changed, 564 insertions, 291 deletions
diff --git a/lib/libc/sys/sendfile.2 b/lib/libc/sys/sendfile.2 index b363382..2b52dd9 100644 --- a/lib/libc/sys/sendfile.2 +++ b/lib/libc/sys/sendfile.2 @@ -25,7 +25,7 @@ .\" .\" $FreeBSD$ .\" -.Dd January 7, 2010 +.Dd January 7, 2016 .Dt SENDFILE 2 .Os .Sh NAME @@ -46,7 +46,7 @@ The .Fn sendfile system call -sends a regular file specified by descriptor +sends a regular file or shared memory object specified by descriptor .Fa fd out a stream socket specified by descriptor .Fa s . @@ -101,32 +101,55 @@ the system will write the total number of bytes sent on the socket to the variable pointed to by .Fa sbytes . .Pp -The +The least significant 16 bits of .Fa flags argument is a bitmap of these values: -.Bl -item -offset indent -.It -.Dv SF_NODISKIO . -This flag causes any -.Fn sendfile -call which would block on disk I/O to instead -return -.Er EBUSY . -Busy servers may benefit by transferring requests that would -block to a separate I/O worker thread. -.It -.Dv SF_MNOWAIT . -Do not wait for some kernel resource to become available, -in particular, -.Vt mbuf -and -.Vt sf_buf . -The flag does not make the -.Fn sendfile -syscall truly non-blocking, since other resources are still allocated -in a blocking fashion. -.It -.Dv SF_SYNC . +.Bl -tag -offset indent +.It Dv SF_NODISKIO +This flag causes +.Nm +to return +.Er EBUSY +instead of blocking when a busy page is encountered. +This rare situation can happen if some other process is now working +with the same region of the file. +It is advised to retry the operation after a short period. +.Pp +Note that in older +.Fx +versions the +.Dv SF_NODISKIO +had slightly different notion. +The flag prevented +.Nm +to run I/O operations in case if an invalid (not cached) page is encountered, +thus avoiding blocking on I/O. +Starting with +.Fx 11 +.Nm +sending files off the +.Xr ffs 7 +filesystem doesn't block on I/O +(see +.Sx IMPLEMENTATION NOTES +), so the condition no longer applies. +However, it is safe if an application utilizes +.Dv SF_NODISKIO +and on +.Er EBUSY +performs the same action as it did in +older +.Fx +versions, e.g. +.Xr aio_read 2, +.Xr read 2 +or +.Nm +in a different context. +.It Dv SF_NOCACHE +The data sent to socket will not be cached by the virtual memory system, +and will be freed directly to the pool of free pages. +.It Dv SF_SYNC .Nm sleeps until the network stack no longer references the VM pages of the file, making subsequent modifications to it safe. @@ -134,6 +157,22 @@ Please note that this is not a guarantee that the data has actually been sent. .El .Pp +The most significant 16 bits of +.Fa flags +specify amount of pages that +.Nm +may read ahead when reading the file. +A macro +.Fn SF_FLAGS +is provided to combine readahead amount and flags. +Example shows specifing readahead of 16 pages and +.Dv SF_NOCACHE +flag: +.Pp +.Bd -literal -offset indent -compact + SF_FLAGS(16, SF_NOCACHE) +.Ed +.Pp When using a socket marked for non-blocking I/O, .Fn sendfile may send fewer bytes than requested. @@ -149,6 +188,18 @@ The .Fx implementation of .Fn sendfile +doesn't block on disk I/O when it sends a file off the +.Xr ffs 7 +filesystem. +The syscall returns success before the actual I/O completes, and data +is put into the socket later unattended. +However, the order of data in the socket is preserved, so it is safe +to do further writes to the socket. +.Pp +The +.Fx +implementation of +.Fn sendfile is "zero-copy", meaning that it has been optimized so that copying of the file data is avoided. .Sh TUNING On some architectures, this system call internally uses a special @@ -232,12 +283,10 @@ The argument is not a valid socket descriptor. .It Bq Er EBUSY -Completing the entire transfer would have required disk I/O, so -it was aborted. -Partial data may have been sent. -(This error can only occur when +A busy page was encountered and .Dv SF_NODISKIO -is specified.) +had been specified. +Partial data may have been sent. .It Bq Er EFAULT An invalid address was specified for an argument. .It Bq Er EINTR @@ -310,9 +359,19 @@ first appeared in .Fx 3.0 . This manual page first appeared in .Fx 3.1 . +In +.Fx 10 +support for sending shared memory descriptors had been introduced. +In +.Fx 11 +a non-blocking implementation had been introduced. .Sh AUTHORS -The +The initial implementation of .Fn sendfile system call and this manual page were written by .An David G. Lawrence Aq Mt dg@dglawrence.com . +The +.Fx 11 +implementation was written by +.An Gleb Smirnoff Aq Mt glebius@FreeBSD.org . diff --git a/sys/dev/ti/if_ti.c b/sys/dev/ti/if_ti.c index 9b9c4a1..eba7f7b 100644 --- a/sys/dev/ti/if_ti.c +++ b/sys/dev/ti/if_ti.c @@ -1634,7 +1634,7 @@ ti_newbuf_jumbo(struct ti_softc *sc, int idx, struct mbuf *m_old) m[i]->m_data = (void *)sf_buf_kva(sf[i]); m[i]->m_len = PAGE_SIZE; MEXTADD(m[i], sf_buf_kva(sf[i]), PAGE_SIZE, - sf_buf_mext, (void*)sf_buf_kva(sf[i]), sf[i], + sf_mext_free, (void*)sf_buf_kva(sf[i]), sf[i], 0, EXT_DISPOSABLE); m[i]->m_next = m[i+1]; } @@ -1699,7 +1699,7 @@ nobufs: if (m[i]) m_freem(m[i]); if (sf[i]) - sf_buf_mext((void *)sf_buf_kva(sf[i]), sf[i]); + sf_mext_free((void *)sf_buf_kva(sf[i]), sf[i]); } return (ENOBUFS); } diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c index de6b313..0b0b697 100644 --- a/sys/kern/uipc_mbuf.c +++ b/sys/kern/uipc_mbuf.c @@ -338,6 +338,9 @@ mb_free_ext(struct mbuf *m) case EXT_SFBUF: sf_ext_free(m->m_ext.ext_arg1, m->m_ext.ext_arg2); break; + case EXT_SFBUF_NOCACHE: + sf_ext_free_nocache(m->m_ext.ext_arg1, m->m_ext.ext_arg2); + break; default: KASSERT(m->m_ext.ext_cnt != NULL, ("%s: no refcounting pointer on %p", __func__, m)); @@ -404,6 +407,7 @@ mb_dupcl(struct mbuf *n, const struct mbuf *m) switch (m->m_ext.ext_type) { case EXT_SFBUF: + case EXT_SFBUF_NOCACHE: sf_ext_ref(m->m_ext.ext_arg1, m->m_ext.ext_arg2); break; default: diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c index c33a2cf..cac698a 100644 --- a/sys/kern/uipc_syscalls.c +++ b/sys/kern/uipc_syscalls.c @@ -113,15 +113,6 @@ static int getpeername1(struct thread *td, struct getpeername_args *uap, counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)]; -/* - * sendfile(2)-related variables and associated sysctls - */ -static SYSCTL_NODE(_kern_ipc, OID_AUTO, sendfile, CTLFLAG_RW, 0, - "sendfile(2) tunables"); -static int sfreadahead = 1; -SYSCTL_INT(_kern_ipc_sendfile, OID_AUTO, readahead, CTLFLAG_RW, - &sfreadahead, 0, "Number of sendfile(2) read-ahead MAXBSIZE blocks"); - static void sfstat_init(const void *unused) { @@ -1858,13 +1849,12 @@ sf_ext_free(void *arg1, void *arg2) sf_buf_free(sf); vm_page_lock(pg); - vm_page_unwire(pg, PQ_INACTIVE); /* * Check for the object going away on us. This can * happen since we don't hold a reference to it. * If so, we're responsible for freeing the page. */ - if (pg->wire_count == 0 && pg->object == NULL) + if (vm_page_unwire(pg, PQ_INACTIVE) && pg->object == NULL) vm_page_free(pg); vm_page_unlock(pg); @@ -1878,6 +1868,43 @@ sf_ext_free(void *arg1, void *arg2) } /* + * Same as above, but forces the page to be detached from the object + * and go into free pool. + */ +void +sf_ext_free_nocache(void *arg1, void *arg2) +{ + struct sf_buf *sf = arg1; + struct sendfile_sync *sfs = arg2; + vm_page_t pg = sf_buf_page(sf); + + sf_buf_free(sf); + + vm_page_lock(pg); + if (vm_page_unwire(pg, PQ_NONE)) { + vm_object_t obj; + + /* Try to free the page, but only if it is cheap to. */ + if ((obj = pg->object) == NULL) + vm_page_free(pg); + else if (!vm_page_xbusied(pg) && VM_OBJECT_TRYWLOCK(obj)) { + vm_page_free(pg); + VM_OBJECT_WUNLOCK(obj); + } else + vm_page_deactivate(pg); + } + vm_page_unlock(pg); + + if (sfs != NULL) { + mtx_lock(&sfs->mtx); + KASSERT(sfs->count > 0, ("Sendfile sync botchup count == 0")); + if (--sfs->count == 0) + cv_signal(&sfs->cv); + mtx_unlock(&sfs->mtx); + } +} + +/* * sendfile(2) * * int sendfile(int fd, int s, off_t offset, size_t nbytes, @@ -1974,103 +2001,252 @@ freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap) } #endif /* COMPAT_FREEBSD4 */ + /* + * How much data to put into page i of n. + * Only first and last pages are special. + */ +static inline off_t +xfsize(int i, int n, off_t off, off_t len) +{ + + if (i == 0) + return (omin(PAGE_SIZE - (off & PAGE_MASK), len)); + + if (i == n - 1 && ((off + len) & PAGE_MASK) > 0) + return ((off + len) & PAGE_MASK); + + return (PAGE_SIZE); +} + +/* + * Offset within object for i page. + */ +static inline vm_offset_t +vmoff(int i, off_t off) +{ + + if (i == 0) + return ((vm_offset_t)off); + + return (trunc_page(off + i * PAGE_SIZE)); +} + +/* + * Pretend as if we don't have enough space, subtract xfsize() of + * all pages that failed. + */ +static inline void +fixspace(int old, int new, off_t off, int *space) +{ + + KASSERT(old > new, ("%s: old %d new %d", __func__, old, new)); + + /* Subtract last one. */ + *space -= xfsize(old - 1, old, off, *space); + old--; + + if (new == old) + /* There was only one page. */ + return; + + /* Subtract first one. */ + if (new == 0) { + *space -= xfsize(0, old, off, *space); + new++; + } + + /* Rest of pages are full sized. */ + *space -= (old - new) * PAGE_SIZE; + + KASSERT(*space >= 0, ("%s: space went backwards", __func__)); +} + +/* + * Structure describing a single sendfile(2) I/O, which may consist of + * several underlying pager I/Os. + * + * The syscall context allocates the structure and initializes 'nios' + * to 1. As sendfile_swapin() runs through pages and starts asynchronous + * paging operations, it increments 'nios'. + * + * Every I/O completion calls sf_iodone(), which decrements the 'nios', and + * the syscall also calls sf_iodone() after allocating all mbufs, linking them + * and sending to socket. Whoever reaches zero 'nios' is responsible to + * call pru_ready on the socket, to notify it of readyness of the data. + */ +struct sf_io { + volatile u_int nios; + u_int error; + int npages; + struct file *sock_fp; + struct mbuf *m; + vm_page_t pa[]; +}; + +static void +sf_iodone(void *arg, vm_page_t *pg, int count, int error) +{ + struct sf_io *sfio = arg; + struct socket *so; + + for (int i = 0; i < count; i++) + vm_page_xunbusy(pg[i]); + + if (error) + sfio->error = error; + + if (!refcount_release(&sfio->nios)) + return; + + so = sfio->sock_fp->f_data; + + if (sfio->error) { + struct mbuf *m; + + /* + * I/O operation failed. The state of data in the socket + * is now inconsistent, and all what we can do is to tear + * it down. Protocol abort method would tear down protocol + * state, free all ready mbufs and detach not ready ones. + * We will free the mbufs corresponding to this I/O manually. + * + * The socket would be marked with EIO and made available + * for read, so that application receives EIO on next + * syscall and eventually closes the socket. + */ + so->so_proto->pr_usrreqs->pru_abort(so); + so->so_error = EIO; + + m = sfio->m; + for (int i = 0; i < sfio->npages; i++) + m = m_free(m); + } else { + CURVNET_SET(so->so_vnet); + (void )(so->so_proto->pr_usrreqs->pru_ready)(so, sfio->m, + sfio->npages); + CURVNET_RESTORE(); + } + + /* XXXGL: curthread */ + fdrop(sfio->sock_fp, curthread); + free(sfio, M_TEMP); +} + +/* + * Iterate through pages vector and request paging for non-valid pages. + */ static int -sendfile_readpage(vm_object_t obj, struct vnode *vp, int nd, - off_t off, int xfsize, int bsize, struct thread *td, vm_page_t *res) +sendfile_swapin(vm_object_t obj, struct sf_io *sfio, off_t off, off_t len, + int npages, int rhpages, int flags) { - vm_page_t m; - vm_pindex_t pindex; - ssize_t resid; - int error, readahead, rv; + vm_page_t *pa = sfio->pa; + int nios; - pindex = OFF_TO_IDX(off); - VM_OBJECT_WLOCK(obj); - m = vm_page_grab(obj, pindex, (vp != NULL ? VM_ALLOC_NOBUSY | - VM_ALLOC_IGN_SBUSY : 0) | VM_ALLOC_WIRED | VM_ALLOC_NORMAL); + nios = 0; + flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0; /* - * Check if page is valid for what we need, otherwise initiate I/O. - * - * The non-zero nd argument prevents disk I/O, instead we - * return the caller what he specified in nd. In particular, - * if we already turned some pages into mbufs, nd == EAGAIN - * and the main function send them the pages before we come - * here again and block. + * First grab all the pages and wire them. Note that we grab + * only required pages. Readahead pages are dealt with later. */ - if (m->valid != 0 && vm_page_is_valid(m, off & PAGE_MASK, xfsize)) { - if (vp == NULL) - vm_page_xunbusy(m); - VM_OBJECT_WUNLOCK(obj); - *res = m; - return (0); - } else if (nd != 0) { - if (vp == NULL) - vm_page_xunbusy(m); - error = nd; - goto free_page; + VM_OBJECT_WLOCK(obj); + for (int i = 0; i < npages; i++) { + pa[i] = vm_page_grab(obj, OFF_TO_IDX(vmoff(i, off)), + VM_ALLOC_WIRED | VM_ALLOC_NORMAL | flags); + if (pa[i] == NULL) { + npages = i; + rhpages = 0; + break; + } } - /* - * Get the page from backing store. - */ - error = 0; - if (vp != NULL) { - VM_OBJECT_WUNLOCK(obj); - readahead = sfreadahead * MAXBSIZE; + for (int i = 0; i < npages;) { + int j, a, count, rv; + + /* Skip valid pages. */ + if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK, + xfsize(i, npages, off, len))) { + vm_page_xunbusy(pa[i]); + SFSTAT_INC(sf_pages_valid); + i++; + continue; + } /* - * Use vn_rdwr() instead of the pager interface for - * the vnode, to allow the read-ahead. - * - * XXXMAC: Because we don't have fp->f_cred here, we - * pass in NOCRED. This is probably wrong, but is - * consistent with our original implementation. + * Now 'i' points to first invalid page, iterate further + * to make 'j' point at first valid after a bunch of + * invalid ones. */ - error = vn_rdwr(UIO_READ, vp, NULL, readahead, trunc_page(off), - UIO_NOCOPY, IO_NODELOCKED | IO_VMIO | ((readahead / - bsize) << IO_SEQSHIFT), td->td_ucred, NOCRED, &resid, td); - SFSTAT_INC(sf_iocnt); - VM_OBJECT_WLOCK(obj); - } else { - if (vm_pager_has_page(obj, pindex, NULL, NULL)) { - rv = vm_pager_get_pages(obj, &m, 1, NULL, NULL); - SFSTAT_INC(sf_iocnt); - if (rv != VM_PAGER_OK) { - vm_page_lock(m); - vm_page_free(m); - vm_page_unlock(m); - m = NULL; - error = EIO; + for (j = i + 1; j < npages; j++) + if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK, + xfsize(j, npages, off, len))) { + SFSTAT_INC(sf_pages_valid); + break; } - } else { - pmap_zero_page(m); - m->valid = VM_PAGE_BITS_ALL; - m->dirty = 0; + + /* + * Now we got region of invalid pages between 'i' and 'j'. + * Check that they belong to pager. They may not be there, + * which is a regular situation for shmem pager. For vnode + * pager this happens only in case of sparse file. + * + * Important feature of vm_pager_has_page() is the hint + * stored in 'a', about how many pages we can pagein after + * this page in a single I/O. + */ + while (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), + NULL, &a) && i < j) { + pmap_zero_page(pa[i]); + pa[i]->valid = VM_PAGE_BITS_ALL; + pa[i]->dirty = 0; + vm_page_xunbusy(pa[i]); + i++; } - if (m != NULL) - vm_page_xunbusy(m); - } - if (error == 0) { - *res = m; - } else if (m != NULL) { -free_page: - vm_page_lock(m); - vm_page_unwire(m, PQ_INACTIVE); + if (i == j) + continue; /* - * See if anyone else might know about this page. If - * not and it is not valid, then free it. + * We want to pagein as many pages as possible, limited only + * by the 'a' hint and actual request. + * + * We should not pagein into already valid page, thus if + * 'j' didn't reach last page, trim by that page. + * + * When the pagein fulfils the request, also specify readahead. */ - if (m->wire_count == 0 && m->valid == 0 && !vm_page_busied(m)) - vm_page_free(m); - vm_page_unlock(m); - } - KASSERT(error != 0 || (m->wire_count > 0 && - vm_page_is_valid(m, off & PAGE_MASK, xfsize)), - ("wrong page state m %p off %#jx xfsize %d", m, (uintmax_t)off, - xfsize)); + if (j < npages) + a = min(a, j - i - 1); + count = min(a + 1, npages - i); + + refcount_acquire(&sfio->nios); + rv = vm_pager_get_pages_async(obj, pa + i, count, NULL, + i + count == npages ? &rhpages : NULL, + &sf_iodone, sfio); + KASSERT(rv == VM_PAGER_OK, ("%s: pager fail obj %p page %p", + __func__, obj, pa[i])); + + SFSTAT_INC(sf_iocnt); + SFSTAT_ADD(sf_pages_read, count); + if (i + count == npages) + SFSTAT_ADD(sf_rhpages_read, rhpages); + +#ifdef INVARIANTS + for (j = i; j < i + count && j < npages; j++) + KASSERT(pa[j] == vm_page_lookup(obj, + OFF_TO_IDX(vmoff(j, off))), + ("pa[j] %p lookup %p\n", pa[j], + vm_page_lookup(obj, OFF_TO_IDX(vmoff(j, off))))); +#endif + i += count; + nios++; + } + VM_OBJECT_WUNLOCK(obj); - return (error); + + if (nios == 0 && npages != 0) + SFSTAT_INC(sf_noiocnt); + + return (nios); } static int @@ -2178,42 +2354,37 @@ vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, struct vnode *vp; struct vm_object *obj; struct socket *so; - struct mbuf *m; + struct mbuf *m, *mh, *mhtail; struct sf_buf *sf; - struct vm_page *pg; struct shmfd *shmfd; struct sendfile_sync *sfs; struct vattr va; - off_t off, xfsize, fsbytes, sbytes, rem, obj_size; - int error, bsize, nd, hdrlen, mnw; + off_t off, sbytes, rem, obj_size; + int error, softerr, bsize, hdrlen; - pg = NULL; obj = NULL; so = NULL; - m = NULL; + m = mh = NULL; sfs = NULL; - fsbytes = sbytes = 0; - hdrlen = mnw = 0; - rem = nbytes; - obj_size = 0; + sbytes = 0; + softerr = 0; error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize); if (error != 0) return (error); - if (rem == 0) - rem = obj_size; error = kern_sendfile_getsock(td, sockfd, &sock_fp, &so); if (error != 0) goto out; - /* - * Do not wait on memory allocations but return ENOMEM for - * caller to retry later. - * XXX: Experimental. - */ - if (flags & SF_MNOWAIT) - mnw = 1; +#ifdef MAC + error = mac_socket_check_send(td->td_ucred, so); + if (error != 0) + goto out; +#endif + + SFSTAT_INC(sf_syscalls); + SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags)); if (flags & SF_SYNC) { sfs = malloc(sizeof *sfs, M_TEMP, M_WAITOK | M_ZERO); @@ -2221,37 +2392,27 @@ vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, cv_init(&sfs->cv, "sendfile"); } -#ifdef MAC - error = mac_socket_check_send(td->td_ucred, so); - if (error != 0) - goto out; -#endif - /* If headers are specified copy them into mbufs. */ - if (hdr_uio != NULL) { + if (hdr_uio != NULL && hdr_uio->uio_resid > 0) { hdr_uio->uio_td = td; hdr_uio->uio_rw = UIO_WRITE; - if (hdr_uio->uio_resid > 0) { - /* - * In FBSD < 5.0 the nbytes to send also included - * the header. If compat is specified subtract the - * header size from nbytes. - */ - if (kflags & SFK_COMPAT) { - if (nbytes > hdr_uio->uio_resid) - nbytes -= hdr_uio->uio_resid; - else - nbytes = 0; - } - m = m_uiotombuf(hdr_uio, (mnw ? M_NOWAIT : M_WAITOK), - 0, 0, 0); - if (m == NULL) { - error = mnw ? EAGAIN : ENOBUFS; - goto out; - } - hdrlen = m_length(m, NULL); + /* + * In FBSD < 5.0 the nbytes to send also included + * the header. If compat is specified subtract the + * header size from nbytes. + */ + if (kflags & SFK_COMPAT) { + if (nbytes > hdr_uio->uio_resid) + nbytes -= hdr_uio->uio_resid; + else + nbytes = 0; } - } + mh = m_uiotombuf(hdr_uio, M_WAITOK, 0, 0, 0); + hdrlen = m_length(mh, &mhtail); + } else + hdrlen = 0; + + rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset; /* * Protect against multiple writers to the socket. @@ -2272,21 +2433,13 @@ vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, * The outer loop checks the state and available space of the socket * and takes care of the overall progress. */ - for (off = offset; ; ) { + for (off = offset; rem > 0; ) { + struct sf_io *sfio; + vm_page_t *pa; struct mbuf *mtail; - int loopbytes; - int space; - int done; - - if ((nbytes != 0 && nbytes == fsbytes) || - (nbytes == 0 && obj_size == fsbytes)) - break; + int nios, space, npages, rhpages; mtail = NULL; - loopbytes = 0; - space = 0; - done = 0; - /* * Check the socket state for ongoing connection, * no errors and space in socket buffer. @@ -2362,49 +2515,58 @@ retry_space: VOP_UNLOCK(vp, 0); goto done; } - obj_size = va.va_size; + if (va.va_size != obj_size) { + if (nbytes == 0) + rem += va.va_size - obj_size; + else if (offset + nbytes > va.va_size) + rem -= (offset + nbytes - va.va_size); + obj_size = va.va_size; + } } + if (space > rem) + space = rem; + + npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE); + + /* + * Calculate maximum allowed number of pages for readahead + * at this iteration. First, we allow readahead up to "rem". + * If application wants more, let it be, but there is no + * reason to go above MAXPHYS. Also check against "obj_size", + * since vm_pager_has_page() can hint beyond EOF. + */ + rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) - npages; + rhpages += SF_READAHEAD(flags); + rhpages = min(howmany(MAXPHYS, PAGE_SIZE), rhpages); + rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) - + npages, rhpages); + + sfio = malloc(sizeof(struct sf_io) + + npages * sizeof(vm_page_t), M_TEMP, M_WAITOK); + refcount_init(&sfio->nios, 1); + sfio->error = 0; + + nios = sendfile_swapin(obj, sfio, off, space, npages, rhpages, + flags); + /* * Loop and construct maximum sized mbuf chain to be bulk * dumped into socket buffer. */ - while (space > loopbytes) { - vm_offset_t pgoff; + pa = sfio->pa; + for (int i = 0; i < npages; i++) { struct mbuf *m0; /* - * Calculate the amount to transfer. - * Not to exceed a page, the EOF, - * or the passed in nbytes. + * If a page wasn't grabbed successfully, then + * trim the array. Can happen only with SF_NODISKIO. */ - pgoff = (vm_offset_t)(off & PAGE_MASK); - rem = obj_size - offset; - if (nbytes != 0) - rem = omin(rem, nbytes); - rem -= fsbytes + loopbytes; - xfsize = omin(PAGE_SIZE - pgoff, rem); - xfsize = omin(space - loopbytes, xfsize); - if (xfsize <= 0) { - done = 1; /* all data sent */ - break; - } - - /* - * Attempt to look up the page. Allocate - * if not found or wait and loop if busy. - */ - if (m != NULL) - nd = EAGAIN; /* send what we already got */ - else if ((flags & SF_NODISKIO) != 0) - nd = EBUSY; - else - nd = 0; - error = sendfile_readpage(obj, vp, nd, off, - xfsize, bsize, td, &pg); - if (error != 0) { - if (error == EAGAIN) - error = 0; /* not a real error */ + if (pa[i] == NULL) { + SFSTAT_INC(sf_busy); + fixspace(npages, i, off, &space); + npages = i; + softerr = EBUSY; break; } @@ -2417,56 +2579,59 @@ retry_space: * threads might exhaust the buffers and then * deadlock. */ - sf = sf_buf_alloc(pg, (mnw || m != NULL) ? SFB_NOWAIT : - SFB_CATCH); + sf = sf_buf_alloc(pa[i], + m != NULL ? SFB_NOWAIT : SFB_CATCH); if (sf == NULL) { SFSTAT_INC(sf_allocfail); - vm_page_lock(pg); - vm_page_unwire(pg, PQ_INACTIVE); - KASSERT(pg->object != NULL, - ("%s: object disappeared", __func__)); - vm_page_unlock(pg); + for (int j = i; j < npages; j++) { + vm_page_lock(pa[j]); + vm_page_unwire(pa[j], PQ_INACTIVE); + vm_page_unlock(pa[j]); + } if (m == NULL) - error = (mnw ? EAGAIN : EINTR); + softerr = ENOBUFS; + fixspace(npages, i, off, &space); + npages = i; break; } - /* - * Get an mbuf and set it up as having - * external storage. - */ - m0 = m_get((mnw ? M_NOWAIT : M_WAITOK), MT_DATA); - if (m0 == NULL) { - error = (mnw ? EAGAIN : ENOBUFS); - sf_ext_free(sf, NULL); - break; - } - /* - * Attach EXT_SFBUF external storage. - */ - m0->m_ext.ext_buf = (caddr_t )sf_buf_kva(sf); + m0 = m_get(M_WAITOK, MT_DATA); + m0->m_ext.ext_buf = (char *)sf_buf_kva(sf); m0->m_ext.ext_size = PAGE_SIZE; m0->m_ext.ext_arg1 = sf; m0->m_ext.ext_arg2 = sfs; - m0->m_ext.ext_type = EXT_SFBUF; + /* + * SF_NOCACHE sets the page as being freed upon send. + * However, we ignore it for the last page in 'space', + * if the page is truncated, and we got more data to + * send (rem > space), or if we have readahead + * configured (rhpages > 0). + */ + if ((flags & SF_NOCACHE) == 0 || + (i == npages - 1 && + ((off + space) & PAGE_MASK) && + (rem > space || rhpages > 0))) + m0->m_ext.ext_type = EXT_SFBUF; + else + m0->m_ext.ext_type = EXT_SFBUF_NOCACHE; m0->m_ext.ext_flags = 0; - m0->m_flags |= (M_EXT|M_RDONLY); - m0->m_data = (char *)sf_buf_kva(sf) + pgoff; - m0->m_len = xfsize; + m0->m_flags |= (M_EXT | M_RDONLY); + if (nios) + m0->m_flags |= M_NOTREADY; + m0->m_data = (char *)sf_buf_kva(sf) + + (vmoff(i, off) & PAGE_MASK); + m0->m_len = xfsize(i, npages, off, space); + + if (i == 0) + sfio->m = m0; /* Append to mbuf chain. */ if (mtail != NULL) mtail->m_next = m0; - else if (m != NULL) - m_last(m)->m_next = m0; else m = m0; mtail = m0; - /* Keep track of bits processed. */ - loopbytes += xfsize; - off += xfsize; - if (sfs != NULL) { mtx_lock(&sfs->mtx); sfs->count++; @@ -2477,49 +2642,60 @@ retry_space: if (vp != NULL) VOP_UNLOCK(vp, 0); + /* Keep track of bytes processed. */ + off += space; + rem -= space; + + /* Prepend header, if any. */ + if (hdrlen) { + mhtail->m_next = m; + m = mh; + mh = NULL; + } + + if (m == NULL) { + KASSERT(softerr, ("%s: m NULL, no error", __func__)); + error = softerr; + free(sfio, M_TEMP); + goto done; + } + /* Add the buffer chain to the socket buffer. */ - if (m != NULL) { - int mlen, err; + KASSERT(m_length(m, NULL) == space + hdrlen, + ("%s: mlen %u space %d hdrlen %d", + __func__, m_length(m, NULL), space, hdrlen)); - mlen = m_length(m, NULL); - SOCKBUF_LOCK(&so->so_snd); - if (so->so_snd.sb_state & SBS_CANTSENDMORE) { - error = EPIPE; - SOCKBUF_UNLOCK(&so->so_snd); - goto done; - } - SOCKBUF_UNLOCK(&so->so_snd); - CURVNET_SET(so->so_vnet); - /* Avoid error aliasing. */ - err = (*so->so_proto->pr_usrreqs->pru_send) - (so, 0, m, NULL, NULL, td); - CURVNET_RESTORE(); - if (err == 0) { - /* - * We need two counters to get the - * file offset and nbytes to send - * right: - * - sbytes contains the total amount - * of bytes sent, including headers. - * - fsbytes contains the total amount - * of bytes sent from the file. - */ - sbytes += mlen; - fsbytes += mlen; - if (hdrlen) { - fsbytes -= hdrlen; - hdrlen = 0; - } - } else if (error == 0) - error = err; - m = NULL; /* pru_send always consumes */ + CURVNET_SET(so->so_vnet); + if (nios == 0) { + /* + * If sendfile_swapin() didn't initiate any I/Os, + * which happens if all data is cached in VM, then + * we can send data right now without the + * PRUS_NOTREADY flag. + */ + free(sfio, M_TEMP); + error = (*so->so_proto->pr_usrreqs->pru_send) + (so, 0, m, NULL, NULL, td); + } else { + sfio->sock_fp = sock_fp; + sfio->npages = npages; + fhold(sock_fp); + error = (*so->so_proto->pr_usrreqs->pru_send) + (so, PRUS_NOTREADY, m, NULL, NULL, td); + sf_iodone(sfio, NULL, 0, 0); } + CURVNET_RESTORE(); - /* Quit outer loop on error or when we're done. */ - if (done) - break; - if (error != 0) + m = NULL; /* pru_send always consumes */ + if (error) goto done; + sbytes += space + hdrlen; + if (hdrlen) + hdrlen = 0; + if (softerr) { + error = softerr; + goto done; + } } /* @@ -2552,6 +2728,8 @@ out: fdrop(sock_fp, td); if (m) m_freem(m); + if (mh) + m_freem(mh); if (sfs != NULL) { mtx_lock(&sfs->mtx); diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h index 8509a6c..91dd895 100644 --- a/sys/sys/mbuf.h +++ b/sys/sys/mbuf.h @@ -343,12 +343,13 @@ struct mbuf { * External mbuf storage buffer types. */ #define EXT_CLUSTER 1 /* mbuf cluster */ -#define EXT_SFBUF 2 /* sendfile(2)'s sf_bufs */ +#define EXT_SFBUF 2 /* sendfile(2)'s sf_buf */ #define EXT_JUMBOP 3 /* jumbo cluster page sized */ #define EXT_JUMBO9 4 /* jumbo cluster 9216 bytes */ #define EXT_JUMBO16 5 /* jumbo cluster 16184 bytes */ #define EXT_PACKET 6 /* mbuf+cluster from packet zone */ #define EXT_MBUF 7 /* external mbuf reference (M_IOVEC) */ +#define EXT_SFBUF_NOCACHE 8 /* sendfile(2)'s sf_buf not to be cached */ #define EXT_VENDOR1 224 /* for vendor-internal use */ #define EXT_VENDOR2 225 /* for vendor-internal use */ @@ -397,6 +398,7 @@ struct mbuf { */ void sf_ext_ref(void *, void *); void sf_ext_free(void *, void *); +void sf_ext_free_nocache(void *, void *); /* * Flags indicating checksum, segmentation and other offload work to be diff --git a/sys/sys/sf_buf.h b/sys/sys/sf_buf.h index d3bb037..b5970d9 100644 --- a/sys/sys/sf_buf.h +++ b/sys/sys/sf_buf.h @@ -31,7 +31,14 @@ #define _SYS_SF_BUF_H_ struct sfstat { /* sendfile statistics */ + uint64_t sf_syscalls; /* times sendfile was called */ + uint64_t sf_noiocnt; /* times sendfile didn't require I/O */ uint64_t sf_iocnt; /* times sendfile had to do disk I/O */ + uint64_t sf_pages_read; /* pages read as part of a request */ + uint64_t sf_pages_valid; /* pages were valid for a request */ + uint64_t sf_rhpages_requested; /* readahead pages requested */ + uint64_t sf_rhpages_read; /* readahead pages read */ + uint64_t sf_busy; /* times aborted on a busy page */ uint64_t sf_allocfail; /* times sfbuf allocation failed */ uint64_t sf_allocwait; /* times sfbuf allocation had to wait */ }; diff --git a/sys/sys/socket.h b/sys/sys/socket.h index 18e2de1..ee621d9 100644 --- a/sys/sys/socket.h +++ b/sys/sys/socket.h @@ -587,11 +587,14 @@ struct sf_hdtr { * Sendfile-specific flag(s) */ #define SF_NODISKIO 0x00000001 -#define SF_MNOWAIT 0x00000002 +#define SF_MNOWAIT 0x00000002 /* obsolete */ #define SF_SYNC 0x00000004 +#define SF_NOCACHE 0x00000010 +#define SF_FLAGS(rh, flags) (((rh) << 16) | (flags)) #ifdef _KERNEL #define SFK_COMPAT 0x00000001 +#define SF_READAHEAD(flags) ((flags) >> 16) #endif /* _KERNEL */ #endif /* __BSD_VISIBLE */ diff --git a/usr.bin/netstat/mbuf.c b/usr.bin/netstat/mbuf.c index baf7a65..8b95ddd 100644 --- a/usr.bin/netstat/mbuf.c +++ b/usr.bin/netstat/mbuf.c @@ -326,13 +326,33 @@ mbpr(void *kvmd, u_long mbaddr) kread_counters) != 0) goto out; + xo_emit("{:sendfile-syscalls/%ju} {N:sendfile syscalls}\n", + (uintmax_t)sfstat.sf_syscalls); + xo_emit("{:sendfile-no-io/%ju} " + "{N:sendfile syscalls completed without I\\/O request}\n", + (uintmax_t)sfstat.sf_noiocnt); + xo_emit("{:sendfile-io-count/%ju} " + "{N:requests for I\\/O initiated by sendfile}\n", + (uintmax_t)sfstat.sf_iocnt); + xo_emit("{:sendfile-pages-sent/%ju} " + "{N:pages read by sendfile as part of a request}\n", + (uintmax_t)sfstat.sf_pages_read); + xo_emit("{:sendfile-pages-valid/%ju} " + "{N:pages were valid at time of a sendfile request}\n", + (uintmax_t)sfstat.sf_pages_valid); + xo_emit("{:sendfile-requested-readahead/%ju} " + "{N:pages were requested for read ahead by applications}\n", + (uintmax_t)sfstat.sf_rhpages_requested); + xo_emit("{:sendfile-readahead/%ju} " + "{N:pages were read ahead by sendfile}\n", + (uintmax_t)sfstat.sf_rhpages_read); + xo_emit("{:sendfile-busy-encounters/%ju} " + "{N:times sendfile encountered an already busy page}\n", + (uintmax_t)sfstat.sf_busy); xo_emit("{:sfbufs-alloc-failed/%ju} {N:requests for sfbufs denied}\n", (uintmax_t)sfstat.sf_allocfail); xo_emit("{:sfbufs-alloc-wait/%ju} {N:requests for sfbufs delayed}\n", (uintmax_t)sfstat.sf_allocwait); - xo_emit("{:sfbufs-io-count/%ju} " - "{N:requests for I\\/O initiated by sendfile}\n", - (uintmax_t)sfstat.sf_iocnt); out: xo_close_container("mbuf-statistics"); memstat_mtl_free(mtlp); |
