Mercurial > hg > nginx
view src/core/ngx_buf.c @ 7670:ccb5ff87ab3e
Cache: introduced min_free cache clearing.
Clearing cache based on free space left on a file system is
expected to allow better disk utilization in some cases, notably
when disk space might be also used for something other than nginx
cache (including nginx own temporary files) and while loading
cache (when cache size might be inaccurate for a while, effectively
disabling max_size cache clearing).
Based on a patch by Adam Bambuch.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 22 Jun 2020 18:03:00 +0300 |
parents | da9941c9b01b |
children | c7a8bdf5af55 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> ngx_buf_t * ngx_create_temp_buf(ngx_pool_t *pool, size_t size) { ngx_buf_t *b; b = ngx_calloc_buf(pool); if (b == NULL) { return NULL; } b->start = ngx_palloc(pool, size); if (b->start == NULL) { return NULL; } /* * set by ngx_calloc_buf(): * * b->file_pos = 0; * b->file_last = 0; * b->file = NULL; * b->shadow = NULL; * b->tag = 0; * and flags */ b->pos = b->start; b->last = b->start; b->end = b->last + size; b->temporary = 1; return b; } ngx_chain_t * ngx_alloc_chain_link(ngx_pool_t *pool) { ngx_chain_t *cl; cl = pool->chain; if (cl) { pool->chain = cl->next; return cl; } cl = ngx_palloc(pool, sizeof(ngx_chain_t)); if (cl == NULL) { return NULL; } return cl; } ngx_chain_t * ngx_create_chain_of_bufs(ngx_pool_t *pool, ngx_bufs_t *bufs) { u_char *p; ngx_int_t i; ngx_buf_t *b; ngx_chain_t *chain, *cl, **ll; p = ngx_palloc(pool, bufs->num * bufs->size); if (p == NULL) { return NULL; } ll = &chain; for (i = 0; i < bufs->num; i++) { b = ngx_calloc_buf(pool); if (b == NULL) { return NULL; } /* * set by ngx_calloc_buf(): * * b->file_pos = 0; * b->file_last = 0; * b->file = NULL; * b->shadow = NULL; * b->tag = 0; * and flags * */ b->pos = p; b->last = p; b->temporary = 1; b->start = p; p += bufs->size; b->end = p; cl = ngx_alloc_chain_link(pool); if (cl == NULL) { return NULL; } cl->buf = b; *ll = cl; ll = &cl->next; } *ll = NULL; return chain; } ngx_int_t ngx_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain, ngx_chain_t *in) { ngx_chain_t *cl, **ll; ll = chain; for (cl = *chain; cl; cl = cl->next) { ll = &cl->next; } while (in) { cl = ngx_alloc_chain_link(pool); if (cl == NULL) { *ll = NULL; return NGX_ERROR; } cl->buf = in->buf; *ll = cl; ll = &cl->next; in = in->next; } *ll = NULL; return NGX_OK; } ngx_chain_t * ngx_chain_get_free_buf(ngx_pool_t *p, ngx_chain_t **free) { ngx_chain_t *cl; if (*free) { cl = *free; *free = cl->next; cl->next = NULL; return cl; } cl = ngx_alloc_chain_link(p); if (cl == NULL) { return NULL; } cl->buf = ngx_calloc_buf(p); if (cl->buf == NULL) { return NULL; } cl->next = NULL; return cl; } void ngx_chain_update_chains(ngx_pool_t *p, ngx_chain_t **free, ngx_chain_t **busy, ngx_chain_t **out, ngx_buf_tag_t tag) { ngx_chain_t *cl; if (*out) { if (*busy == NULL) { *busy = *out; } else { for (cl = *busy; cl->next; cl = cl->next) { /* void */ } cl->next = *out; } *out = NULL; } while (*busy) { cl = *busy; if (ngx_buf_size(cl->buf) != 0) { break; } if (cl->buf->tag != tag) { *busy = cl->next; ngx_free_chain(p, cl); continue; } cl->buf->pos = cl->buf->start; cl->buf->last = cl->buf->start; *busy = cl->next; cl->next = *free; *free = cl; } } off_t ngx_chain_coalesce_file(ngx_chain_t **in, off_t limit) { off_t total, size, aligned, fprev; ngx_fd_t fd; ngx_chain_t *cl; total = 0; cl = *in; fd = cl->buf->file->fd; do { size = cl->buf->file_last - cl->buf->file_pos; if (size > limit - total) { size = limit - total; aligned = (cl->buf->file_pos + size + ngx_pagesize - 1) & ~((off_t) ngx_pagesize - 1); if (aligned <= cl->buf->file_last) { size = aligned - cl->buf->file_pos; } total += size; break; } total += size; fprev = cl->buf->file_pos + size; cl = cl->next; } while (cl && cl->buf->in_file && total < limit && fd == cl->buf->file->fd && fprev == cl->buf->file_pos); *in = cl; return total; } ngx_chain_t * ngx_chain_update_sent(ngx_chain_t *in, off_t sent) { off_t size; for ( /* void */ ; in; in = in->next) { if (ngx_buf_special(in->buf)) { continue; } if (sent == 0) { break; } size = ngx_buf_size(in->buf); if (sent >= size) { sent -= size; if (ngx_buf_in_memory(in->buf)) { in->buf->pos = in->buf->last; } if (in->buf->in_file) { in->buf->file_pos = in->buf->file_last; } continue; } if (ngx_buf_in_memory(in->buf)) { in->buf->pos += (size_t) sent; } if (in->buf->in_file) { in->buf->file_pos += sent; } break; } return in; }