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c9fa0480af
Now the buffers only contain the header and a pointer to the storage area which can be anywhere. This will significantly simplify buffer swapping and will make it possible to map chunks on buffers as well. The buf_empty variable was removed, as now it's enough to have size==0 and area==NULL to designate the empty buffer (thus a non-allocated head is the empty buffer by default). buf_wanted for now is indicated by size==0 and area==(void *)1. The channels and the checks now embed the buffer's head, and the only pointer is to the storage area. This slightly increases the unallocated buffer size (3 extra ints for the empty buffer) but considerably simplifies dynamic buffer management. It will also later permit to detach unused checks. The way the struct buffer is arranged has proven quite efficient on a number of tests, which makes sense given that size is always accessed and often first, followed by the othe ones.
142 lines
3.9 KiB
C
142 lines
3.9 KiB
C
/*
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* Buffer management functions.
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*
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* Copyright 2000-2012 Willy Tarreau <w@1wt.eu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
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#include <common/config.h>
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#include <common/buffer.h>
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#include <common/memory.h>
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#include <types/global.h>
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struct pool_head *pool_head_buffer;
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/* list of objects waiting for at least one buffer */
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struct list buffer_wq = LIST_HEAD_INIT(buffer_wq);
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__decl_hathreads(HA_SPINLOCK_T __attribute__((aligned(64))) buffer_wq_lock);
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/* perform minimal intializations, report 0 in case of error, 1 if OK. */
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int init_buffer()
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{
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void *buffer;
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pool_head_buffer = create_pool("buffer", global.tune.bufsize, MEM_F_SHARED|MEM_F_EXACT);
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if (!pool_head_buffer)
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return 0;
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/* The reserved buffer is what we leave behind us. Thus we always need
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* at least one extra buffer in minavail otherwise we'll end up waking
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* up tasks with no memory available, causing a lot of useless wakeups.
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* That means that we always want to have at least 3 buffers available
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* (2 for current session, one for next session that might be needed to
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* release a server connection).
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*/
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pool_head_buffer->minavail = MAX(global.tune.reserved_bufs, 3);
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if (global.tune.buf_limit)
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pool_head_buffer->limit = global.tune.buf_limit;
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HA_SPIN_INIT(&buffer_wq_lock);
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buffer = pool_refill_alloc(pool_head_buffer, pool_head_buffer->minavail - 1);
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if (!buffer)
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return 0;
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pool_free(pool_head_buffer, buffer);
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return 1;
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}
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void deinit_buffer()
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{
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pool_destroy(pool_head_buffer);
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}
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/*
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* Dumps part or all of a buffer.
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*/
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void buffer_dump(FILE *o, struct buffer *b, int from, int to)
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{
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fprintf(o, "Dumping buffer %p\n", b);
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fprintf(o, " orig=%p size=%u head=%u tail=%u data=%u\n",
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b_orig(b), (unsigned int)b_size(b), (unsigned int)b_head_ofs(b), (unsigned int)b_tail_ofs(b), (unsigned int)b_data(b));
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fprintf(o, "Dumping contents from byte %d to byte %d\n", from, to);
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fprintf(o, " 0 1 2 3 4 5 6 7 8 9 a b c d e f\n");
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/* dump hexa */
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while (from < to) {
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int i;
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fprintf(o, " %04x: ", from);
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for (i = 0; ((from + i) < to) && (i < 16) ; i++) {
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fprintf(o, "%02x ", (unsigned char)b_orig(b)[from + i]);
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if (((from + i) & 15) == 7)
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fprintf(o, "- ");
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}
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if (to - from < 16) {
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int j = 0;
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for (j = 0; j < from + 16 - to; j++)
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fprintf(o, " ");
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if (j > 8)
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fprintf(o, " ");
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}
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fprintf(o, " ");
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for (i = 0; (from + i < to) && (i < 16) ; i++) {
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fprintf(o, "%c", isprint((int)b_orig(b)[from + i]) ? b_orig(b)[from + i] : '.') ;
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if ((((from + i) & 15) == 15) && ((from + i) != to-1))
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fprintf(o, "\n");
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}
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from += i;
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}
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fprintf(o, "\n--\n");
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fflush(o);
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}
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/* see offer_buffer() for details */
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void __offer_buffer(void *from, unsigned int threshold)
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{
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struct buffer_wait *wait, *bak;
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int avail;
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/* For now, we consider that all objects need 1 buffer, so we can stop
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* waking up them once we have enough of them to eat all the available
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* buffers. Note that we don't really know if they are streams or just
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* other tasks, but that's a rough estimate. Similarly, for each cached
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* event we'll need 1 buffer. If no buffer is currently used, always
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* wake up the number of tasks we can offer a buffer based on what is
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* allocated, and in any case at least one task per two reserved
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* buffers.
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*/
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avail = pool_head_buffer->allocated - pool_head_buffer->used - global.tune.reserved_bufs / 2;
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list_for_each_entry_safe(wait, bak, &buffer_wq, list) {
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if (avail <= threshold)
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break;
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if (wait->target == from || !wait->wakeup_cb(wait->target))
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continue;
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LIST_DEL(&wait->list);
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LIST_INIT(&wait->list);
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avail--;
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}
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}
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/*
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* Local variables:
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* c-indent-level: 8
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* c-basic-offset: 8
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* End:
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*/
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