Mercurial > hg > nginx-quic
view src/core/ngx_slab.c @ 6750:cb330cd39030 stable-1.10
HTTP/2: implemented preread buffer for request body (closes #959).
Previously, the stream's window was kept zero in order to prevent a client
from sending the request body before it was requested (see 887cca40ba6a for
details). Until such initial window was acknowledged all requests with
data were rejected (see 0aa07850922f for details).
That approach revealed a number of problems:
1. Some clients (notably MS IE/Edge, Safari, iOS applications) show an error
or even crash if a stream is rejected;
2. This requires at least one RTT for every request with body before the
client receives window update and able to send data.
To overcome these problems the new directive "http2_body_preread_size" is
introduced. It sets the initial window and configures a special per stream
preread buffer that is used to save all incoming data before the body is
requested and processed.
If the directive's value is lower than the default initial window (65535),
as previously, all streams with data will be rejected until the new window
is acknowledged. Otherwise, no special processing is used and all requests
with data are welcome right from the connection start.
The default value is chosen to be 64k, which is bigger than the default
initial window. Setting it to zero is fully complaint to the previous
behavior.
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Tue, 24 May 2016 17:37:52 +0300 |
parents | f01ab2dbcfdc |
children | ea76a3aa18ae |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #define NGX_SLAB_PAGE_MASK 3 #define NGX_SLAB_PAGE 0 #define NGX_SLAB_BIG 1 #define NGX_SLAB_EXACT 2 #define NGX_SLAB_SMALL 3 #if (NGX_PTR_SIZE == 4) #define NGX_SLAB_PAGE_FREE 0 #define NGX_SLAB_PAGE_BUSY 0xffffffff #define NGX_SLAB_PAGE_START 0x80000000 #define NGX_SLAB_SHIFT_MASK 0x0000000f #define NGX_SLAB_MAP_MASK 0xffff0000 #define NGX_SLAB_MAP_SHIFT 16 #define NGX_SLAB_BUSY 0xffffffff #else /* (NGX_PTR_SIZE == 8) */ #define NGX_SLAB_PAGE_FREE 0 #define NGX_SLAB_PAGE_BUSY 0xffffffffffffffff #define NGX_SLAB_PAGE_START 0x8000000000000000 #define NGX_SLAB_SHIFT_MASK 0x000000000000000f #define NGX_SLAB_MAP_MASK 0xffffffff00000000 #define NGX_SLAB_MAP_SHIFT 32 #define NGX_SLAB_BUSY 0xffffffffffffffff #endif #if (NGX_DEBUG_MALLOC) #define ngx_slab_junk(p, size) ngx_memset(p, 0xA5, size) #elif (NGX_HAVE_DEBUG_MALLOC) #define ngx_slab_junk(p, size) \ if (ngx_debug_malloc) ngx_memset(p, 0xA5, size) #else #define ngx_slab_junk(p, size) #endif static ngx_slab_page_t *ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages); static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page, ngx_uint_t pages); static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text); static ngx_uint_t ngx_slab_max_size; static ngx_uint_t ngx_slab_exact_size; static ngx_uint_t ngx_slab_exact_shift; void ngx_slab_init(ngx_slab_pool_t *pool) { u_char *p; size_t size; ngx_int_t m; ngx_uint_t i, n, pages; ngx_slab_page_t *slots; /* STUB */ if (ngx_slab_max_size == 0) { ngx_slab_max_size = ngx_pagesize / 2; ngx_slab_exact_size = ngx_pagesize / (8 * sizeof(uintptr_t)); for (n = ngx_slab_exact_size; n >>= 1; ngx_slab_exact_shift++) { /* void */ } } /**/ pool->min_size = 1 << pool->min_shift; p = (u_char *) pool + sizeof(ngx_slab_pool_t); size = pool->end - p; ngx_slab_junk(p, size); slots = (ngx_slab_page_t *) p; n = ngx_pagesize_shift - pool->min_shift; for (i = 0; i < n; i++) { slots[i].slab = 0; slots[i].next = &slots[i]; slots[i].prev = 0; } p += n * sizeof(ngx_slab_page_t); pages = (ngx_uint_t) (size / (ngx_pagesize + sizeof(ngx_slab_page_t))); ngx_memzero(p, pages * sizeof(ngx_slab_page_t)); pool->pages = (ngx_slab_page_t *) p; pool->free.prev = 0; pool->free.next = (ngx_slab_page_t *) p; pool->pages->slab = pages; pool->pages->next = &pool->free; pool->pages->prev = (uintptr_t) &pool->free; pool->start = (u_char *) ngx_align_ptr((uintptr_t) p + pages * sizeof(ngx_slab_page_t), ngx_pagesize); m = pages - (pool->end - pool->start) / ngx_pagesize; if (m > 0) { pages -= m; pool->pages->slab = pages; } pool->last = pool->pages + pages; pool->log_nomem = 1; pool->log_ctx = &pool->zero; pool->zero = '\0'; } void * ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size) { void *p; ngx_shmtx_lock(&pool->mutex); p = ngx_slab_alloc_locked(pool, size); ngx_shmtx_unlock(&pool->mutex); return p; } void * ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size) { size_t s; uintptr_t p, n, m, mask, *bitmap; ngx_uint_t i, slot, shift, map; ngx_slab_page_t *page, *prev, *slots; if (size > ngx_slab_max_size) { ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz", size); page = ngx_slab_alloc_pages(pool, (size >> ngx_pagesize_shift) + ((size % ngx_pagesize) ? 1 : 0)); if (page) { p = (page - pool->pages) << ngx_pagesize_shift; p += (uintptr_t) pool->start; } else { p = 0; } goto done; } if (size > pool->min_size) { shift = 1; for (s = size - 1; s >>= 1; shift++) { /* void */ } slot = shift - pool->min_shift; } else { size = pool->min_size; shift = pool->min_shift; slot = 0; } ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz slot: %ui", size, slot); slots = (ngx_slab_page_t *) ((u_char *) pool + sizeof(ngx_slab_pool_t)); page = slots[slot].next; if (page->next != page) { if (shift < ngx_slab_exact_shift) { do { p = (page - pool->pages) << ngx_pagesize_shift; bitmap = (uintptr_t *) (pool->start + p); map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8); for (n = 0; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { for (m = 1, i = 0; m; m <<= 1, i++) { if ((bitmap[n] & m)) { continue; } bitmap[n] |= m; i = ((n * sizeof(uintptr_t) * 8) << shift) + (i << shift); if (bitmap[n] == NGX_SLAB_BUSY) { for (n = n + 1; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { p = (uintptr_t) bitmap + i; goto done; } } prev = (ngx_slab_page_t *) (page->prev & ~NGX_SLAB_PAGE_MASK); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_SMALL; } p = (uintptr_t) bitmap + i; goto done; } } } page = page->next; } while (page); } else if (shift == ngx_slab_exact_shift) { do { if (page->slab != NGX_SLAB_BUSY) { for (m = 1, i = 0; m; m <<= 1, i++) { if ((page->slab & m)) { continue; } page->slab |= m; if (page->slab == NGX_SLAB_BUSY) { prev = (ngx_slab_page_t *) (page->prev & ~NGX_SLAB_PAGE_MASK); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_EXACT; } p = (page - pool->pages) << ngx_pagesize_shift; p += i << shift; p += (uintptr_t) pool->start; goto done; } } page = page->next; } while (page); } else { /* shift > ngx_slab_exact_shift */ n = ngx_pagesize_shift - (page->slab & NGX_SLAB_SHIFT_MASK); n = 1 << n; n = ((uintptr_t) 1 << n) - 1; mask = n << NGX_SLAB_MAP_SHIFT; do { if ((page->slab & NGX_SLAB_MAP_MASK) != mask) { for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0; m & mask; m <<= 1, i++) { if ((page->slab & m)) { continue; } page->slab |= m; if ((page->slab & NGX_SLAB_MAP_MASK) == mask) { prev = (ngx_slab_page_t *) (page->prev & ~NGX_SLAB_PAGE_MASK); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_BIG; } p = (page - pool->pages) << ngx_pagesize_shift; p += i << shift; p += (uintptr_t) pool->start; goto done; } } page = page->next; } while (page); } } page = ngx_slab_alloc_pages(pool, 1); if (page) { if (shift < ngx_slab_exact_shift) { p = (page - pool->pages) << ngx_pagesize_shift; bitmap = (uintptr_t *) (pool->start + p); s = 1 << shift; n = (1 << (ngx_pagesize_shift - shift)) / 8 / s; if (n == 0) { n = 1; } bitmap[0] = (2 << n) - 1; map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8); for (i = 1; i < map; i++) { bitmap[i] = 0; } page->slab = shift; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL; slots[slot].next = page; p = ((page - pool->pages) << ngx_pagesize_shift) + s * n; p += (uintptr_t) pool->start; goto done; } else if (shift == ngx_slab_exact_shift) { page->slab = 1; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT; slots[slot].next = page; p = (page - pool->pages) << ngx_pagesize_shift; p += (uintptr_t) pool->start; goto done; } else { /* shift > ngx_slab_exact_shift */ page->slab = ((uintptr_t) 1 << NGX_SLAB_MAP_SHIFT) | shift; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG; slots[slot].next = page; p = (page - pool->pages) << ngx_pagesize_shift; p += (uintptr_t) pool->start; goto done; } } p = 0; done: ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %p", (void *) p); return (void *) p; } void * ngx_slab_calloc(ngx_slab_pool_t *pool, size_t size) { void *p; ngx_shmtx_lock(&pool->mutex); p = ngx_slab_calloc_locked(pool, size); ngx_shmtx_unlock(&pool->mutex); return p; } void * ngx_slab_calloc_locked(ngx_slab_pool_t *pool, size_t size) { void *p; p = ngx_slab_alloc_locked(pool, size); if (p) { ngx_memzero(p, size); } return p; } void ngx_slab_free(ngx_slab_pool_t *pool, void *p) { ngx_shmtx_lock(&pool->mutex); ngx_slab_free_locked(pool, p); ngx_shmtx_unlock(&pool->mutex); } void ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p) { size_t size; uintptr_t slab, m, *bitmap; ngx_uint_t n, type, slot, shift, map; ngx_slab_page_t *slots, *page; ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab free: %p", p); if ((u_char *) p < pool->start || (u_char *) p > pool->end) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): outside of pool"); goto fail; } n = ((u_char *) p - pool->start) >> ngx_pagesize_shift; page = &pool->pages[n]; slab = page->slab; type = page->prev & NGX_SLAB_PAGE_MASK; switch (type) { case NGX_SLAB_SMALL: shift = slab & NGX_SLAB_SHIFT_MASK; size = 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } n = ((uintptr_t) p & (ngx_pagesize - 1)) >> shift; m = (uintptr_t) 1 << (n & (sizeof(uintptr_t) * 8 - 1)); n /= (sizeof(uintptr_t) * 8); bitmap = (uintptr_t *) ((uintptr_t) p & ~((uintptr_t) ngx_pagesize - 1)); if (bitmap[n] & m) { if (page->next == NULL) { slots = (ngx_slab_page_t *) ((u_char *) pool + sizeof(ngx_slab_pool_t)); slot = shift - pool->min_shift; page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL; page->next->prev = (uintptr_t) page | NGX_SLAB_SMALL; } bitmap[n] &= ~m; n = (1 << (ngx_pagesize_shift - shift)) / 8 / (1 << shift); if (n == 0) { n = 1; } if (bitmap[0] & ~(((uintptr_t) 1 << n) - 1)) { goto done; } map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8); for (n = 1; n < map; n++) { if (bitmap[n]) { goto done; } } ngx_slab_free_pages(pool, page, 1); goto done; } goto chunk_already_free; case NGX_SLAB_EXACT: m = (uintptr_t) 1 << (((uintptr_t) p & (ngx_pagesize - 1)) >> ngx_slab_exact_shift); size = ngx_slab_exact_size; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } if (slab & m) { if (slab == NGX_SLAB_BUSY) { slots = (ngx_slab_page_t *) ((u_char *) pool + sizeof(ngx_slab_pool_t)); slot = ngx_slab_exact_shift - pool->min_shift; page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT; page->next->prev = (uintptr_t) page | NGX_SLAB_EXACT; } page->slab &= ~m; if (page->slab) { goto done; } ngx_slab_free_pages(pool, page, 1); goto done; } goto chunk_already_free; case NGX_SLAB_BIG: shift = slab & NGX_SLAB_SHIFT_MASK; size = 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } m = (uintptr_t) 1 << ((((uintptr_t) p & (ngx_pagesize - 1)) >> shift) + NGX_SLAB_MAP_SHIFT); if (slab & m) { if (page->next == NULL) { slots = (ngx_slab_page_t *) ((u_char *) pool + sizeof(ngx_slab_pool_t)); slot = shift - pool->min_shift; page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG; page->next->prev = (uintptr_t) page | NGX_SLAB_BIG; } page->slab &= ~m; if (page->slab & NGX_SLAB_MAP_MASK) { goto done; } ngx_slab_free_pages(pool, page, 1); goto done; } goto chunk_already_free; case NGX_SLAB_PAGE: if ((uintptr_t) p & (ngx_pagesize - 1)) { goto wrong_chunk; } if (slab == NGX_SLAB_PAGE_FREE) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): page is already free"); goto fail; } if (slab == NGX_SLAB_PAGE_BUSY) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): pointer to wrong page"); goto fail; } n = ((u_char *) p - pool->start) >> ngx_pagesize_shift; size = slab & ~NGX_SLAB_PAGE_START; ngx_slab_free_pages(pool, &pool->pages[n], size); ngx_slab_junk(p, size << ngx_pagesize_shift); return; } /* not reached */ return; done: ngx_slab_junk(p, size); return; wrong_chunk: ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): pointer to wrong chunk"); goto fail; chunk_already_free: ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): chunk is already free"); fail: return; } static ngx_slab_page_t * ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages) { ngx_slab_page_t *page, *p; for (page = pool->free.next; page != &pool->free; page = page->next) { if (page->slab >= pages) { if (page->slab > pages) { page[page->slab - 1].prev = (uintptr_t) &page[pages]; page[pages].slab = page->slab - pages; page[pages].next = page->next; page[pages].prev = page->prev; p = (ngx_slab_page_t *) page->prev; p->next = &page[pages]; page->next->prev = (uintptr_t) &page[pages]; } else { p = (ngx_slab_page_t *) page->prev; p->next = page->next; page->next->prev = page->prev; } page->slab = pages | NGX_SLAB_PAGE_START; page->next = NULL; page->prev = NGX_SLAB_PAGE; if (--pages == 0) { return page; } for (p = page + 1; pages; pages--) { p->slab = NGX_SLAB_PAGE_BUSY; p->next = NULL; p->prev = NGX_SLAB_PAGE; p++; } return page; } } if (pool->log_nomem) { ngx_slab_error(pool, NGX_LOG_CRIT, "ngx_slab_alloc() failed: no memory"); } return NULL; } static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page, ngx_uint_t pages) { ngx_uint_t type; ngx_slab_page_t *prev, *join; page->slab = pages--; if (pages) { ngx_memzero(&page[1], pages * sizeof(ngx_slab_page_t)); } if (page->next) { prev = (ngx_slab_page_t *) (page->prev & ~NGX_SLAB_PAGE_MASK); prev->next = page->next; page->next->prev = page->prev; } join = page + page->slab; if (join < pool->last) { type = join->prev & NGX_SLAB_PAGE_MASK; if (type == NGX_SLAB_PAGE) { if (join->next != NULL) { pages += join->slab; page->slab += join->slab; prev = (ngx_slab_page_t *) (join->prev & ~NGX_SLAB_PAGE_MASK); prev->next = join->next; join->next->prev = join->prev; join->slab = NGX_SLAB_PAGE_FREE; join->next = NULL; join->prev = NGX_SLAB_PAGE; } } } if (page > pool->pages) { join = page - 1; type = join->prev & NGX_SLAB_PAGE_MASK; if (type == NGX_SLAB_PAGE) { if (join->slab == NGX_SLAB_PAGE_FREE) { join = (ngx_slab_page_t *) (join->prev & ~NGX_SLAB_PAGE_MASK); } if (join->next != NULL) { pages += join->slab; join->slab += page->slab; prev = (ngx_slab_page_t *) (join->prev & ~NGX_SLAB_PAGE_MASK); prev->next = join->next; join->next->prev = join->prev; page->slab = NGX_SLAB_PAGE_FREE; page->next = NULL; page->prev = NGX_SLAB_PAGE; page = join; } } } if (pages) { page[pages].prev = (uintptr_t) page; } page->prev = (uintptr_t) &pool->free; page->next = pool->free.next; page->next->prev = (uintptr_t) page; pool->free.next = page; } static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text) { ngx_log_error(level, ngx_cycle->log, 0, "%s%s", text, pool->log_ctx); }