130 lines
2.4 KiB
C
130 lines
2.4 KiB
C
/*
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* BIRD Internet Routing Daemon -- Raw allocation
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*
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* (c) 2020 Maria Matejka <mq@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#include "nest/bird.h"
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#include "lib/resource.h"
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#include "lib/lists.h"
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#include "lib/event.h"
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#include <stdlib.h>
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#include <unistd.h>
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#ifdef HAVE_MMAP
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#include <sys/mman.h>
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#endif
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#ifdef HAVE_MMAP
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#define KEEP_PAGES 512
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static u64 page_size = 0;
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static _Bool use_fake = 0;
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uint pages_kept = 0;
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static list pages_list;
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static void cleanup_pages(void *data);
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static event page_cleanup_event = { .hook = cleanup_pages };
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#else
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static const u64 page_size = 4096; /* Fake page size */
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#endif
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u64 get_page_size(void)
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{
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if (page_size)
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return page_size;
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#ifdef HAVE_MMAP
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if (page_size = sysconf(_SC_PAGESIZE))
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{
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if ((u64_popcount(page_size) > 1) || (page_size > 16384))
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{
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/* Too big or strange page, use the aligned allocator instead */
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page_size = 4096;
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use_fake = 1;
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}
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return page_size;
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}
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bug("Page size must be non-zero");
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#endif
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}
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void *
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alloc_page(void)
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{
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#ifdef HAVE_MMAP
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if (pages_kept)
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{
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node *page = TAIL(pages_list);
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rem_node(page);
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pages_kept--;
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memset(page, 0, get_page_size());
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return page;
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}
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if (!use_fake)
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{
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void *ret = mmap(NULL, get_page_size(), PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (ret == MAP_FAILED)
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bug("mmap(%lu) failed: %m", page_size);
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return ret;
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}
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else
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#endif
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{
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void *ret = aligned_alloc(page_size, page_size);
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if (!ret)
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bug("aligned_alloc(%lu) failed", page_size);
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return ret;
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}
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}
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void
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free_page(void *ptr)
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{
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#ifdef HAVE_MMAP
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if (!use_fake)
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{
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if (!pages_kept)
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init_list(&pages_list);
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memset(ptr, 0, sizeof(node));
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add_tail(&pages_list, ptr);
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if (++pages_kept > KEEP_PAGES)
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ev_schedule(&page_cleanup_event);
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}
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else
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#endif
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free(ptr);
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}
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#ifdef HAVE_MMAP
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static void
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cleanup_pages(void *data UNUSED)
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{
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for (uint seen = 0; (pages_kept > KEEP_PAGES) && (seen < KEEP_PAGES); seen++)
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{
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void *ptr = HEAD(pages_list);
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rem_node(ptr);
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if (munmap(ptr, get_page_size()) == 0)
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pages_kept--;
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#ifdef ENOMEM
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else if (errno == ENOMEM)
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add_tail(&pages_list, ptr);
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#endif
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else
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bug("munmap(%p) failed: %m", ptr);
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}
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if (pages_kept > KEEP_PAGES)
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ev_schedule(&page_cleanup_event);
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}
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#endif
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