A few minor mods (improvements) to support more efficient pipe
operations for large transfers. There are essentially no differences for small transfers, but big transfers should perform about 20% better.
This commit is contained in:
John Dyson
parent
56d18eda29
commit
d1a5be1064
@ -16,7 +16,7 @@
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* 4. Modifications may be freely made to this file if the above conditions
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* are met.
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*
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* $Id: sys_pipe.c,v 1.18 1996/07/04 04:36:56 dyson Exp $
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* $Id: sys_pipe.c,v 1.19 1996/07/12 08:14:58 bde Exp $
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*/
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#ifndef OLD_PIPE
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@ -122,6 +122,13 @@ static struct fileops pipeops =
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* the amount of kva for pipes in general though.
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*/
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#define LIMITPIPEKVA (16*1024*1024)
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/*
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* Limit the number of "big" pipes
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*/
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#define LIMITBIGPIPES 32
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int nbigpipe;
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static int amountpipekva;
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static void pipeclose __P((struct pipe *cpipe));
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@ -238,6 +245,7 @@ pipeinit(cpipe)
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cpipe->pipe_buffer.out = 0;
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cpipe->pipe_buffer.cnt = 0;
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cpipe->pipe_buffer.size = PIPE_SIZE;
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/* Buffer kva gets dynamically allocated */
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cpipe->pipe_buffer.buffer = NULL;
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/* cpipe->pipe_buffer.object = invalid */
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@ -310,26 +318,6 @@ pipeselwakeup(cpipe)
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}
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}
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#ifndef PIPE_NODIRECT
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#if 0
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static void
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pipe_mark_pages_clean(cpipe)
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struct pipe *cpipe;
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{
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vm_size_t off;
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vm_page_t m;
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for(off = 0; off < cpipe->pipe_buffer.object->size; off += 1) {
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m = vm_page_lookup(cpipe->pipe_buffer.object, off);
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if ((m != NULL) && (m->busy == 0) && (m->flags & PG_BUSY) == 0) {
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m->dirty = 0;
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pmap_clear_modify(VM_PAGE_TO_PHYS(m));
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}
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}
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}
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#endif
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#endif
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/* ARGSUSED */
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static int
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pipe_read(fp, uio, cred)
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@ -459,15 +447,12 @@ pipe_read(fp, uio, cred)
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* its pointers to the beginning. This improves
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* cache hit stats.
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*/
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if ((error == 0) && (error = pipelock(rpipe,1)) == 0) {
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if (rpipe->pipe_buffer.cnt == 0) {
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#if 0
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pipe_mark_pages_clean(rpipe);
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#endif
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if (rpipe->pipe_buffer.cnt == 0) {
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if ((error == 0) && (error = pipelock(rpipe,1)) == 0) {
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rpipe->pipe_buffer.in = 0;
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rpipe->pipe_buffer.out = 0;
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pipeunlock(rpipe);
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}
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pipeunlock(rpipe);
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}
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/*
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@ -567,9 +552,9 @@ pipe_destroy_write_buffer(wpipe)
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struct pipe *wpipe;
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{
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int i;
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pmap_qremove(wpipe->pipe_map.kva, wpipe->pipe_map.npages);
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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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vm_offset_t kva = wpipe->pipe_map.kva;
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wpipe->pipe_map.kva = 0;
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@ -722,6 +707,49 @@ pipe_write(fp, uio, cred)
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return EPIPE;
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}
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/*
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* If it is advantageous to resize the pipe buffer, do
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* so.
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*/
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if ((uio->uio_resid > PIPE_SIZE) &&
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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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(wpipe->pipe_buffer.cnt == 0)) {
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if (wpipe->pipe_buffer.buffer) {
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amountpipekva -= wpipe->pipe_buffer.size;
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kmem_free(kernel_map,
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(vm_offset_t)wpipe->pipe_buffer.buffer,
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wpipe->pipe_buffer.size);
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}
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#ifndef PIPE_NODIRECT
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if (wpipe->pipe_map.kva) {
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amountpipekva -= wpipe->pipe_buffer.size + PAGE_SIZE;
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kmem_free(kernel_map,
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wpipe->pipe_map.kva,
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wpipe->pipe_buffer.size + PAGE_SIZE);
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}
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#endif
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wpipe->pipe_buffer.in = 0;
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wpipe->pipe_buffer.out = 0;
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wpipe->pipe_buffer.cnt = 0;
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wpipe->pipe_buffer.size = BIG_PIPE_SIZE;
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wpipe->pipe_buffer.buffer = NULL;
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++nbigpipe;
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#ifndef PIPE_NODIRECT
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wpipe->pipe_map.cnt = 0;
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wpipe->pipe_map.kva = 0;
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wpipe->pipe_map.pos = 0;
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wpipe->pipe_map.npages = 0;
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#endif
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}
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if( wpipe->pipe_buffer.buffer == NULL) {
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if ((error = pipelock(wpipe,1)) == 0) {
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pipespace(wpipe);
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@ -742,8 +770,9 @@ pipe_write(fp, uio, cred)
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* If the write is non-blocking, we don't use the
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* direct write mechanism.
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*/
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if ((fp->f_flag & FNONBLOCK) == 0 &&
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(amountpipekva < LIMITPIPEKVA) &&
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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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(wpipe->pipe_map.kva || (amountpipekva < LIMITPIPEKVA)) &&
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(uio->uio_iov->iov_len >= PIPE_MINDIRECT)) {
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error = pipe_direct_write( wpipe, uio);
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if (error) {
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@ -778,10 +807,20 @@ pipe_write(fp, uio, cred)
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if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
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space = 0;
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if (space > 0) {
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if (space > 0 && (wpipe->pipe_buffer.cnt < PIPE_SIZE)) {
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/*
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* This set the maximum transfer as a segment of
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* the buffer.
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*/
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int size = wpipe->pipe_buffer.size - wpipe->pipe_buffer.in;
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/*
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* space is the size left in the buffer
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*/
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if (size > space)
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size = space;
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/*
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* now limit it to the size of the uio transfer
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*/
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if (size > uio->uio_resid)
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size = uio->uio_resid;
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if ((error = pipelock(wpipe,1)) == 0) {
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@ -1044,6 +1083,8 @@ pipeclose(cpipe)
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* free resources
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*/
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if (cpipe->pipe_buffer.buffer) {
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if (cpipe->pipe_buffer.size > PIPE_SIZE)
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--nbigpipe;
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amountpipekva -= cpipe->pipe_buffer.size;
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kmem_free(kernel_map,
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(vm_offset_t)cpipe->pipe_buffer.buffer,
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@ -18,7 +18,7 @@
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* 5. Modifications may be freely made to this file if the above conditions
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* are met.
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*
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* $Id: pipe.h,v 1.4 1996/05/01 04:18:20 bde Exp $
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* $Id: pipe.h,v 1.5 1996/07/12 05:44:30 bde Exp $
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*/
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#ifndef _SYS_PIPE_H_
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@ -40,6 +40,10 @@
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#define PIPE_SIZE 16384
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#endif
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#ifndef BIG_PIPE_SIZE
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#define BIG_PIPE_SIZE (64*1024)
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#endif
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/*
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* PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
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* than PIPE_BUF.
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@ -48,7 +52,7 @@
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#define PIPE_MINDIRECT 8192
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#endif
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#define PIPENPAGES (PIPE_SIZE / PAGE_SIZE + 1)
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#define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
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/*
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* Pipe buffer information.
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