Mercurial > hg > nginx-quic
view src/core/ngx_slab.c @ 8867:5119c8150478
Fixed runtime handling of systems without EPOLLRDHUP support.
In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the
ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP
support in the kernel (but with EPOLLRDHUP in headers) was broken.
Before the change, rev->available was never set to 0 unless
ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP
introduced in 6536:f7849bfb6d21 succeeded). After the change,
rev->available might reach 0 on systems without runtime EPOLLRDHUP
support, stopping further reading in ngx_readv_chain() and ngx_unix_recv().
And, if EOF happened to be already reported along with the last event,
it is not reported again by epoll_wait(), leading to connection hangs
and timeouts on such systems.
This affects Linux kernels before 2.6.17 if nginx was compiled
with newer headers, and, more importantly, emulation layers, such as
DigitalOcean's App Platform's / gVisor's epoll emulation layer.
Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding
rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author | Marcus Ball <marcus.ball@live.com> |
---|---|
date | Mon, 30 May 2022 02:38:07 +0300 |
parents | d97d09ef3afe |
children |
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 #define ngx_slab_slots(pool) \ (ngx_slab_page_t *) ((u_char *) (pool) + sizeof(ngx_slab_pool_t)) #define ngx_slab_page_type(page) ((page)->prev & NGX_SLAB_PAGE_MASK) #define ngx_slab_page_prev(page) \ (ngx_slab_page_t *) ((page)->prev & ~NGX_SLAB_PAGE_MASK) #define ngx_slab_page_addr(pool, page) \ ((((page) - (pool)->pages) << ngx_pagesize_shift) \ + (uintptr_t) (pool)->start) #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_sizes_init(void) { ngx_uint_t n; 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 */ } } 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, *page; pool->min_size = (size_t) 1 << pool->min_shift; slots = ngx_slab_slots(pool); p = (u_char *) slots; size = pool->end - p; ngx_slab_junk(p, size); n = ngx_pagesize_shift - pool->min_shift; for (i = 0; i < n; i++) { /* only "next" is used in list head */ slots[i].slab = 0; slots[i].next = &slots[i]; slots[i].prev = 0; } p += n * sizeof(ngx_slab_page_t); pool->stats = (ngx_slab_stat_t *) p; ngx_memzero(pool->stats, n * sizeof(ngx_slab_stat_t)); p += n * sizeof(ngx_slab_stat_t); size -= n * (sizeof(ngx_slab_page_t) + sizeof(ngx_slab_stat_t)); pages = (ngx_uint_t) (size / (ngx_pagesize + sizeof(ngx_slab_page_t))); pool->pages = (ngx_slab_page_t *) p; ngx_memzero(pool->pages, pages * sizeof(ngx_slab_page_t)); page = pool->pages; /* only "next" is used in list head */ pool->free.slab = 0; pool->free.next = page; pool->free.prev = 0; page->slab = pages; page->next = &pool->free; page->prev = (uintptr_t) &pool->free; pool->start = ngx_align_ptr(p + pages * sizeof(ngx_slab_page_t), ngx_pagesize); m = pages - (pool->end - pool->start) / ngx_pagesize; if (m > 0) { pages -= m; page->slab = pages; } pool->last = pool->pages + pages; pool->pfree = 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, m, mask, *bitmap; ngx_uint_t i, n, 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 = ngx_slab_page_addr(pool, page); } 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 { shift = pool->min_shift; slot = 0; } pool->stats[slot].reqs++; ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz slot: %ui", size, slot); slots = ngx_slab_slots(pool); page = slots[slot].next; if (page->next != page) { if (shift < ngx_slab_exact_shift) { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page); map = (ngx_pagesize >> shift) / (8 * sizeof(uintptr_t)); 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 * 8 * sizeof(uintptr_t) + i) << shift; p = (uintptr_t) bitmap + i; pool->stats[slot].used++; if (bitmap[n] == NGX_SLAB_BUSY) { for (n = n + 1; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { goto done; } } prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_SMALL; } goto done; } } } } else if (shift == ngx_slab_exact_shift) { 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_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_EXACT; } p = ngx_slab_page_addr(pool, page) + (i << shift); pool->stats[slot].used++; goto done; } } else { /* shift > ngx_slab_exact_shift */ mask = ((uintptr_t) 1 << (ngx_pagesize >> shift)) - 1; mask <<= NGX_SLAB_MAP_SHIFT; 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_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_BIG; } p = ngx_slab_page_addr(pool, page) + (i << shift); pool->stats[slot].used++; goto done; } } ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_alloc(): page is busy"); ngx_debug_point(); } page = ngx_slab_alloc_pages(pool, 1); if (page) { if (shift < ngx_slab_exact_shift) { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page); n = (ngx_pagesize >> shift) / ((1 << shift) * 8); if (n == 0) { n = 1; } /* "n" elements for bitmap, plus one requested */ for (i = 0; i < (n + 1) / (8 * sizeof(uintptr_t)); i++) { bitmap[i] = NGX_SLAB_BUSY; } m = ((uintptr_t) 1 << ((n + 1) % (8 * sizeof(uintptr_t)))) - 1; bitmap[i] = m; map = (ngx_pagesize >> shift) / (8 * sizeof(uintptr_t)); for (i = 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; pool->stats[slot].total += (ngx_pagesize >> shift) - n; p = ngx_slab_page_addr(pool, page) + (n << shift); pool->stats[slot].used++; 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; pool->stats[slot].total += 8 * sizeof(uintptr_t); p = ngx_slab_page_addr(pool, page); pool->stats[slot].used++; 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; pool->stats[slot].total += ngx_pagesize >> shift; p = ngx_slab_page_addr(pool, page); pool->stats[slot].used++; goto done; } } p = 0; pool->stats[slot].fails++; 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 i, 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 = ngx_slab_page_type(page); switch (type) { case NGX_SLAB_SMALL: shift = slab & NGX_SLAB_SHIFT_MASK; size = (size_t) 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } n = ((uintptr_t) p & (ngx_pagesize - 1)) >> shift; m = (uintptr_t) 1 << (n % (8 * sizeof(uintptr_t))); n /= 8 * sizeof(uintptr_t); bitmap = (uintptr_t *) ((uintptr_t) p & ~((uintptr_t) ngx_pagesize - 1)); if (bitmap[n] & m) { slot = shift - pool->min_shift; if (page->next == NULL) { slots = ngx_slab_slots(pool); 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 = (ngx_pagesize >> shift) / ((1 << shift) * 8); if (n == 0) { n = 1; } i = n / (8 * sizeof(uintptr_t)); m = ((uintptr_t) 1 << (n % (8 * sizeof(uintptr_t)))) - 1; if (bitmap[i] & ~m) { goto done; } map = (ngx_pagesize >> shift) / (8 * sizeof(uintptr_t)); for (i = i + 1; i < map; i++) { if (bitmap[i]) { goto done; } } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= (ngx_pagesize >> shift) - n; 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) { slot = ngx_slab_exact_shift - pool->min_shift; if (slab == NGX_SLAB_BUSY) { slots = ngx_slab_slots(pool); 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); pool->stats[slot].total -= 8 * sizeof(uintptr_t); goto done; } goto chunk_already_free; case NGX_SLAB_BIG: shift = slab & NGX_SLAB_SHIFT_MASK; size = (size_t) 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) { slot = shift - pool->min_shift; if (page->next == NULL) { slots = ngx_slab_slots(pool); 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); pool->stats[slot].total -= ngx_pagesize >> shift; 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_START)) { 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; } size = slab & ~NGX_SLAB_PAGE_START; ngx_slab_free_pages(pool, page, size); ngx_slab_junk(p, size << ngx_pagesize_shift); return; } /* not reached */ return; done: pool->stats[slot].used--; 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; pool->pfree -= pages; 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_slab_page_t *prev, *join; pool->pfree += pages; page->slab = pages--; if (pages) { ngx_memzero(&page[1], pages * sizeof(ngx_slab_page_t)); } if (page->next) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; } join = page + page->slab; if (join < pool->last) { if (ngx_slab_page_type(join) == NGX_SLAB_PAGE) { if (join->next != NULL) { pages += join->slab; page->slab += join->slab; prev = ngx_slab_page_prev(join); 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; if (ngx_slab_page_type(join) == NGX_SLAB_PAGE) { if (join->slab == NGX_SLAB_PAGE_FREE) { join = ngx_slab_page_prev(join); } if (join->next != NULL) { pages += join->slab; join->slab += page->slab; prev = ngx_slab_page_prev(join); 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); }