Author: brooks Date: Mon Sep 2 08:03:29 2019 New Revision: 351690 URL: https://svnweb.freebsd.org/changeset/base/351690
Log: Remove remnants of optimization for > pagesize allocations. In the past, this allocator seems to have allocated things larger than a page seperately. Much of this code was removed at some point (perhaps along with sbrk() used) so remove the rest. Instead, keep allocating in power-of-two bins up to FIRST_BUCKET_SIZE << (NBUCKETS - 1). If we want something more efficent, we should use a fancier allocator. While here, remove some vestages of sbrk() use. Most importantly, don't try to page align the pagepool since it's always page aligned by mmap(). Reviewed by: kib Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D21453 Modified: head/libexec/rtld-elf/rtld_malloc.c Modified: head/libexec/rtld-elf/rtld_malloc.c ============================================================================== --- head/libexec/rtld-elf/rtld_malloc.c Mon Sep 2 08:02:55 2019 (r351689) +++ head/libexec/rtld-elf/rtld_malloc.c Mon Sep 2 08:03:29 2019 (r351690) @@ -89,15 +89,15 @@ static int morepages(int n); #define MAGIC 0xef /* magic # on accounting info */ /* - * nextf[i] is the pointer to the next free block of size 2^(i+3). The - * smallest allocatable block is 8 bytes. The overhead information - * precedes the data area returned to the user. + * nextf[i] is the pointer to the next free block of size + * (FIRST_BUCKET_SIZE << i). The overhead information precedes the data + * area returned to the user. */ +#define FIRST_BUCKET_SIZE 8 #define NBUCKETS 30 static union overhead *nextf[NBUCKETS]; static int pagesz; /* page size */ -static int pagebucket; /* page size bucket */ /* * The array of supported page sizes is provided by the user, i.e., the @@ -112,50 +112,25 @@ __crt_malloc(size_t nbytes) { union overhead *op; int bucket; - ssize_t n; size_t amt; /* - * First time malloc is called, setup page size and - * align break pointer so all data will be page aligned. + * First time malloc is called, setup page size. */ - if (pagesz == 0) { - pagesz = n = pagesizes[0]; - if (morepages(NPOOLPAGES) == 0) - return NULL; - op = (union overhead *)(pagepool_start); - n = n - sizeof (*op) - ((long)op & (n - 1)); - if (n < 0) - n += pagesz; - if (n) { - pagepool_start += n; - } - bucket = 0; - amt = 8; - while ((unsigned)pagesz > amt) { - amt <<= 1; - bucket++; - } - pagebucket = bucket; - } + if (pagesz == 0) + pagesz = pagesizes[0]; /* * Convert amount of memory requested into closest block size * stored in hash buckets which satisfies request. * Account for space used per block for accounting. */ - if (nbytes <= (unsigned long)(n = pagesz - sizeof(*op))) { - amt = 8; /* size of first bucket */ - bucket = 0; - n = -sizeof(*op); - } else { - amt = pagesz; - bucket = pagebucket; - } - while (nbytes > amt + n) { + amt = FIRST_BUCKET_SIZE; + bucket = 0; + while (nbytes > amt - sizeof(*op)) { amt <<= 1; - if (amt == 0) - return (NULL); bucket++; + if (amt == 0 || bucket >= NBUCKETS) + return (NULL); } /* * If nothing in hash bucket right now, @@ -200,18 +175,12 @@ morecore(int bucket) int amt; /* amount to allocate */ int nblks; /* how many blocks we get */ - /* - * sbrk_size <= 0 only for big, FLUFFY, requests (about - * 2^30 bytes on a VAX, I think) or for a negative arg. - */ - if ((unsigned)bucket >= NBBY * sizeof(int) - 4) - return; - sz = 1 << (bucket + 3); + sz = FIRST_BUCKET_SIZE << bucket; if (sz < pagesz) { amt = pagesz; nblks = amt / sz; } else { - amt = sz + pagesz; + amt = sz; nblks = 1; } if (amt > pagepool_end - pagepool_start) _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
