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https://github.com/brain-hackers/u-boot-brain
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![Marek Vasut](/assets/img/avatar_default.png)
Cache up to 4 kiB entries. 4 kiB is the default block size on ext4, yet the underlying block layer devices usually report support for 512B . In most cases, the 512B support is emulated (ie. SD cards, SSDs, USB sticks etc.) and the real block size of those devices is much bigger. To avoid performance degradation with such devices and FS setup, bump the maximum cache entry size to 4 kiB. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Tom Rini <trini@konsulko.com> Cc: Simon Glass <sjg@chromium.org> Reviewed-by: Tom Rini <trini@konsulko.com>
173 lines
3.7 KiB
C
173 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) Nelson Integration, LLC 2016
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* Author: Eric Nelson<eric@nelint.com>
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*
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*/
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#include <config.h>
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#include <common.h>
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#include <malloc.h>
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#include <part.h>
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#include <linux/ctype.h>
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#include <linux/list.h>
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struct block_cache_node {
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struct list_head lh;
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int iftype;
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int devnum;
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lbaint_t start;
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lbaint_t blkcnt;
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unsigned long blksz;
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char *cache;
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};
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static LIST_HEAD(block_cache);
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static struct block_cache_stats _stats = {
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.max_blocks_per_entry = 8,
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.max_entries = 32
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};
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static struct block_cache_node *cache_find(int iftype, int devnum,
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lbaint_t start, lbaint_t blkcnt,
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unsigned long blksz)
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{
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struct block_cache_node *node;
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list_for_each_entry(node, &block_cache, lh)
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if ((node->iftype == iftype) &&
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(node->devnum == devnum) &&
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(node->blksz == blksz) &&
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(node->start <= start) &&
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(node->start + node->blkcnt >= start + blkcnt)) {
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if (block_cache.next != &node->lh) {
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/* maintain MRU ordering */
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list_del(&node->lh);
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list_add(&node->lh, &block_cache);
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}
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return node;
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}
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return 0;
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}
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int blkcache_read(int iftype, int devnum,
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lbaint_t start, lbaint_t blkcnt,
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unsigned long blksz, void *buffer)
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{
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struct block_cache_node *node = cache_find(iftype, devnum, start,
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blkcnt, blksz);
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if (node) {
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const char *src = node->cache + (start - node->start) * blksz;
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memcpy(buffer, src, blksz * blkcnt);
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debug("hit: start " LBAF ", count " LBAFU "\n",
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start, blkcnt);
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++_stats.hits;
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return 1;
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}
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debug("miss: start " LBAF ", count " LBAFU "\n",
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start, blkcnt);
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++_stats.misses;
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return 0;
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}
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void blkcache_fill(int iftype, int devnum,
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lbaint_t start, lbaint_t blkcnt,
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unsigned long blksz, void const *buffer)
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{
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lbaint_t bytes;
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struct block_cache_node *node;
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/* don't cache big stuff */
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if (blkcnt > _stats.max_blocks_per_entry)
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return;
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if (_stats.max_entries == 0)
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return;
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bytes = blksz * blkcnt;
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if (_stats.max_entries <= _stats.entries) {
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/* pop LRU */
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node = (struct block_cache_node *)block_cache.prev;
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list_del(&node->lh);
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_stats.entries--;
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debug("drop: start " LBAF ", count " LBAFU "\n",
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node->start, node->blkcnt);
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if (node->blkcnt * node->blksz < bytes) {
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free(node->cache);
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node->cache = 0;
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}
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} else {
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node = malloc(sizeof(*node));
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if (!node)
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return;
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node->cache = 0;
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}
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if (!node->cache) {
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node->cache = malloc(bytes);
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if (!node->cache) {
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free(node);
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return;
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}
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}
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debug("fill: start " LBAF ", count " LBAFU "\n",
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start, blkcnt);
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node->iftype = iftype;
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node->devnum = devnum;
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node->start = start;
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node->blkcnt = blkcnt;
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node->blksz = blksz;
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memcpy(node->cache, buffer, bytes);
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list_add(&node->lh, &block_cache);
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_stats.entries++;
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}
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void blkcache_invalidate(int iftype, int devnum)
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{
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struct list_head *entry, *n;
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struct block_cache_node *node;
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list_for_each_safe(entry, n, &block_cache) {
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node = (struct block_cache_node *)entry;
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if ((node->iftype == iftype) &&
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(node->devnum == devnum)) {
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list_del(entry);
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free(node->cache);
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free(node);
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--_stats.entries;
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}
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}
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}
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void blkcache_configure(unsigned blocks, unsigned entries)
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{
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struct block_cache_node *node;
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if ((blocks != _stats.max_blocks_per_entry) ||
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(entries != _stats.max_entries)) {
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/* invalidate cache */
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while (!list_empty(&block_cache)) {
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node = (struct block_cache_node *)block_cache.next;
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list_del(&node->lh);
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free(node->cache);
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free(node);
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}
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_stats.entries = 0;
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}
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_stats.max_blocks_per_entry = blocks;
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_stats.max_entries = entries;
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_stats.hits = 0;
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_stats.misses = 0;
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}
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void blkcache_stats(struct block_cache_stats *stats)
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{
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memcpy(stats, &_stats, sizeof(*stats));
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_stats.hits = 0;
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_stats.misses = 0;
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}
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