Mercurial > hg > nginx-quic
view src/core/ngx_slab.c @ 6536:f7849bfb6d21
Improved EPOLLRDHUP handling.
When it's known that the kernel supports EPOLLRDHUP, there is no need in
additional recv() call to get EOF or error when the flag is absent in the
event generated by the kernel. A special runtime test is done at startup
to detect if EPOLLRDHUP is actually supported by the kernel because
epoll_ctl() silently ignores unknown flags.
With this knowledge it's now possible to drop the "ready" flag for partial
read. Previously, the "ready" flag was kept until the recv() returned EOF
or error. In particular, this change allows the lingering close heuristics
(which relies on the "ready" flag state) to actually work on Linux, and not
wait for more data in most cases.
The "available" flag is now used in the read event with the semantics similar
to the corresponding counter in kqueue.
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Fri, 13 May 2016 17:19:23 +0300 |
parents | f01ab2dbcfdc |
children | ea76a3aa18ae |
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/* * 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); }