More pipe changes:
From alc: Move pageable pipe memory to a seperate kernel submap to avoid awkward vm map interlocking issues. (Bad explanation provided by me.) From me: Rework pipespace accounting code to handle this new layout, and adjust our default values to account for the fact that we now have a solid limit on allocations. Also, remove the "maxpipes" limit, as it no longer has a purpose. (The limit on kva usage solves the problem of having two many pipes.)
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silby
parent
1bb319c248
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@ -77,7 +77,6 @@ int nbuf;
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int nswbuf;
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int maxswzone; /* max swmeta KVA storage */
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int maxbcache; /* max buffer cache KVA storage */
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int maxpipes; /* Limit on # of pipes */
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int maxpipekva; /* Limit on pipe KVA */
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int maxpipekvawired; /* Limit on wired pipe KVA */
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u_quad_t maxtsiz; /* max text size */
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@ -180,19 +179,18 @@ void
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init_param3(long kmempages)
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{
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/*
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* Limit number of pipes to a reasonable fraction of kmap entries,
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* pageable pipe memory usage to 2.5% of the kernel map, and wired
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* pipe memory usage to 1% of the same. Ensure that all have
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* reasonable floors. (See sys_pipe.c for more info.)
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* Limit pageable pipe memory usage to 5% of the kernel map
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* (via pipe_map), and nonpageable pipe memory usage to 2.5%
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* of the same. Ensure that all have reasonable floors.
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* (See sys_pipe.c for more info.)
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*/
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maxpipes = kmempages / 5;
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maxpipekva = (kmempages / 40) * PAGE_SIZE;
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maxpipekvawired = (kmempages / 100) * PAGE_SIZE;
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maxpipekva = (kmempages / 20) * PAGE_SIZE;
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maxpipekvawired = (kmempages / 40) * PAGE_SIZE;
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if (maxpipes < 128)
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maxpipes = 128;
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if (maxpipekva < 512 * 1024)
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maxpipekva = 512 * 1024;
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if (maxpipekvawired < 512 * 1024)
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maxpipekvawired = 512 * 1024;
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TUNABLE_INT_FETCH("kern.ipc.maxpipekva", &maxpipekva);
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}
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@ -43,24 +43,20 @@
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*
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* The constant PIPE_MINDIRECT is chosen to make sure that buffering will
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* happen for small transfers so that the system will not spend all of
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* its time context switching. PIPE_SIZE is constrained by the
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* amount of kernel virtual memory.
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* its time context switching.
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*
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* In order to limit the resource use of pipes, three sysctls exist:
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* In order to limit the resource use of pipes, two sysctls exist:
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*
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* kern.ipc.maxpipes - A limit on the total number of pipes in the system.
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* Note that since pipes are bidirectional, the effective value is this
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* number divided by two.
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*
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* kern.ipc.maxpipekva - This value limits the amount of pageable memory that
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* can be used by pipes. Whenever the amount in use exceeds this value,
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* all new pipes will be SMALL_PIPE_SIZE in size, rather than PIPE_SIZE.
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* Big pipe creation will be limited as well.
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* kern.ipc.maxpipekva - This is a hard limit on the amount of pageable
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* address space available to us in pipe_map. Whenever the amount in use
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* exceeds half of this value, all new pipes will be created with size
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* SMALL_PIPE_SIZE, rather than PIPE_SIZE. Big pipe creation will be limited
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* as well. This value is loader tunable only.
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*
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* kern.ipc.maxpipekvawired - This value limits the amount of memory that may
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* be wired in order to facilitate direct copies using page flipping.
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* Whenever this value is exceeded, pipes will fall back to using regular
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* copies.
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* copies. This value is sysctl controllable at all times.
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*
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* These values are autotuned in subr_param.c.
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*
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@ -182,9 +178,7 @@ static int amountpipekvawired;
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SYSCTL_DECL(_kern_ipc);
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SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipes, CTLFLAG_RW,
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&maxpipes, 0, "Max # of pipes");
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SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RW,
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SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RD,
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&maxpipekva, 0, "Pipe KVA limit");
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SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekvawired, CTLFLAG_RW,
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&maxpipekvawired, 0, "Pipe KVA wired limit");
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@ -339,32 +333,29 @@ pipespace(cpipe, size)
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KASSERT(cpipe->pipe_mtxp == NULL || !mtx_owned(PIPE_MTX(cpipe)),
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("pipespace: pipe mutex locked"));
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if (amountpipes > maxpipes) {
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if (ppsratecheck(&lastfail, &curfail, 1))
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printf("kern.maxpipes exceeded, please see tuning(7).\n");
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return (ENOMEM);
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}
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npages = round_page(size)/PAGE_SIZE;
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size = round_page(size);
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npages = size / PAGE_SIZE;
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/*
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* Create an object, I don't like the idea of paging to/from
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* kernel_object.
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* XXX -- minor change needed here for NetBSD/OpenBSD VM systems.
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*/
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object = vm_object_allocate(OBJT_DEFAULT, npages);
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buffer = (caddr_t) vm_map_min(kernel_map);
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buffer = (caddr_t) vm_map_min(pipe_map);
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/*
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* Insert the object into the kernel map, and allocate kva for it.
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* The map entry is, by default, pageable.
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* XXX -- minor change needed here for NetBSD/OpenBSD VM systems.
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*/
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error = vm_map_find(kernel_map, object, 0,
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error = vm_map_find(pipe_map, object, 0,
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(vm_offset_t *) &buffer, size, 1,
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VM_PROT_ALL, VM_PROT_ALL, 0);
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if (error != KERN_SUCCESS) {
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vm_object_deallocate(object);
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if (ppsratecheck(&lastfail, &curfail, 1))
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printf("kern.maxpipekva exceeded, please see tuning(7).\n");
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return (ENOMEM);
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}
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@ -423,7 +414,7 @@ pipe_create(cpipep)
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/*
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* Reduce to 1/4th pipe size if we're over our global max.
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*/
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if (amountpipekva > maxpipekva)
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if (amountpipekva > maxpipekva / 2)
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error = pipespace(cpipe, SMALL_PIPE_SIZE);
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else
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error = pipespace(cpipe, PIPE_SIZE);
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@ -697,8 +688,6 @@ pipe_build_write_buffer(wpipe, uio)
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vm_page_lock_queues();
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for (j = 0; j < i; j++) {
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vm_page_unhold(wpipe->pipe_map.ms[j]);
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atomic_subtract_int(&amountpipekvawired,
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PAGE_SIZE);
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}
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vm_page_unlock_queues();
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return (EFAULT);
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@ -707,7 +696,6 @@ pipe_build_write_buffer(wpipe, uio)
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m = PHYS_TO_VM_PAGE(paddr);
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vm_page_lock_queues();
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vm_page_hold(m);
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atomic_add_int(&amountpipekvawired, PAGE_SIZE);
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vm_page_unlock_queues();
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wpipe->pipe_map.ms[i] = m;
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}
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@ -730,7 +718,7 @@ pipe_build_write_buffer(wpipe, uio)
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*/
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wpipe->pipe_map.kva = kmem_alloc_nofault(kernel_map,
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wpipe->pipe_buffer.size + PAGE_SIZE);
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atomic_add_int(&amountpipekva,
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atomic_add_int(&amountpipekvawired,
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wpipe->pipe_buffer.size + PAGE_SIZE);
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}
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pmap_qenter(wpipe->pipe_map.kva, wpipe->pipe_map.ms,
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@ -764,19 +752,19 @@ pipe_destroy_write_buffer(wpipe)
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if (wpipe->pipe_map.kva) {
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pmap_qremove(wpipe->pipe_map.kva, wpipe->pipe_map.npages);
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if (amountpipekva > maxpipekva) {
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if (amountpipekvawired > maxpipekvawired / 2) {
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/* Conserve address space */
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vm_offset_t kva = wpipe->pipe_map.kva;
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wpipe->pipe_map.kva = 0;
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kmem_free(kernel_map, kva,
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wpipe->pipe_buffer.size + PAGE_SIZE);
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atomic_subtract_int(&amountpipekva,
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atomic_subtract_int(&amountpipekvawired,
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wpipe->pipe_buffer.size + PAGE_SIZE);
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}
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}
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vm_page_lock_queues();
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for (i = 0; i < wpipe->pipe_map.npages; i++) {
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vm_page_unhold(wpipe->pipe_map.ms[i]);
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atomic_subtract_int(&amountpipekvawired, PAGE_SIZE);
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}
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vm_page_unlock_queues();
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wpipe->pipe_map.npages = 0;
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@ -951,7 +939,7 @@ pipe_write(fp, uio, active_cred, flags, td)
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* so.
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*/
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if ((uio->uio_resid > PIPE_SIZE) &&
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(amountpipekva < maxpipekva) &&
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(amountpipekva < maxpipekva / 2) &&
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(nbigpipe < LIMITBIGPIPES) &&
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(wpipe->pipe_state & PIPE_DIRECTW) == 0 &&
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(wpipe->pipe_buffer.size <= PIPE_SIZE) &&
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@ -998,7 +986,7 @@ pipe_write(fp, uio, active_cred, flags, td)
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*/
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if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) &&
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(fp->f_flag & FNONBLOCK) == 0 &&
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amountpipekvawired < maxpipekvawired) {
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amountpipekvawired + uio->uio_resid < maxpipekvawired) {
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error = pipe_direct_write(wpipe, uio);
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if (error)
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break;
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@ -1404,14 +1392,14 @@ pipe_free_kmem(cpipe)
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atomic_subtract_int(&nbigpipe, 1);
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atomic_subtract_int(&amountpipekva, cpipe->pipe_buffer.size);
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atomic_subtract_int(&amountpipes, 1);
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kmem_free(kernel_map,
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(vm_offset_t)cpipe->pipe_buffer.buffer,
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cpipe->pipe_buffer.size);
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vm_map_remove(pipe_map,
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(vm_offset_t)cpipe->pipe_buffer.buffer,
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(vm_offset_t)cpipe->pipe_buffer.buffer + cpipe->pipe_buffer.size);
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cpipe->pipe_buffer.buffer = NULL;
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}
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#ifndef PIPE_NODIRECT
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if (cpipe->pipe_map.kva != 0) {
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atomic_subtract_int(&amountpipekva,
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atomic_subtract_int(&amountpipekvawired,
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cpipe->pipe_buffer.size + PAGE_SIZE);
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kmem_free(kernel_map,
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cpipe->pipe_map.kva,
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@ -60,7 +60,6 @@
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/*
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* See sys_pipe.c for info on what these limits mean.
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*/
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extern int maxpipes;
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extern int maxpipekva;
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extern int maxpipekvawired;
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@ -75,6 +75,8 @@ __FBSDID("$FreeBSD$");
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/selinfo.h>
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#include <sys/pipe.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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@ -195,6 +197,7 @@ again:
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pager_map->system_map = 1;
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exec_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr,
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(16*(ARG_MAX+(PAGE_SIZE*3))));
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pipe_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr, maxpipekva);
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/*
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* XXX: Mbuf system machine-specific initializations should
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@ -89,6 +89,7 @@ __FBSDID("$FreeBSD$");
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vm_map_t kernel_map=0;
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vm_map_t kmem_map=0;
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vm_map_t exec_map=0;
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vm_map_t pipe_map;
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vm_map_t clean_map=0;
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vm_map_t buffer_map=0;
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@ -73,6 +73,7 @@ extern vm_map_t kernel_map;
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extern vm_map_t kmem_map;
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extern vm_map_t clean_map;
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extern vm_map_t exec_map;
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extern vm_map_t pipe_map;
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extern u_int vm_kmem_size;
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#endif /* _VM_VM_KERN_H_ */
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