Date: Wed, 7 Feb 2018 18:32:52 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r328982 - in head/sys: kern vm Message-ID: <201802071832.w17IWqQp049679@repo.freebsd.org>
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Author: glebius Date: Wed Feb 7 18:32:51 2018 New Revision: 328982 URL: https://svnweb.freebsd.org/changeset/base/328982 Log: Fix three miscalculations in amount of boot pages: o Most of startup zones have struct uma_slab embedded into the slab, so provide macro UMA_SLAB_SPACE and use it instead of UMA_SLAB_SIZE, when calculating how many pages would certain kind of allocations require. Some zones are offpage, so we might have a positive inaccuracy. o The keg for the zone of zones is allocated "dynamically", so we need +1 when calculating amount of pages for kegs. [1] o The zones of zones and zones of kegs have arbitrary alignment of 32, and this also needs to be accounted for. [2] While here, spread more comments and improve diagnostic messages. Reported by: pho [1], jtl [2] Modified: head/sys/kern/subr_vmem.c head/sys/vm/uma_core.c head/sys/vm/uma_int.h head/sys/vm/vm_page.c Modified: head/sys/kern/subr_vmem.c ============================================================================== --- head/sys/kern/subr_vmem.c Wed Feb 7 18:18:33 2018 (r328981) +++ head/sys/kern/subr_vmem.c Wed Feb 7 18:32:51 2018 (r328982) @@ -667,7 +667,8 @@ int vmem_startup_count(void) { - return (howmany(BT_MAXALLOC, UMA_SLAB_SIZE / sizeof(struct vmem_btag))); + return (howmany(BT_MAXALLOC, + UMA_SLAB_SPACE / sizeof(struct vmem_btag))); } #endif Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Wed Feb 7 18:18:33 2018 (r328981) +++ head/sys/vm/uma_core.c Wed Feb 7 18:32:51 2018 (r328982) @@ -1102,7 +1102,7 @@ startup_alloc(uma_zone_t zone, vm_size_t bytes, int do } mtx_unlock(&uma_boot_pages_mtx); if (booted < BOOT_PAGEALLOC) - panic("UMA: Increase vm.boot_pages"); + panic("UMA zone \"%s\": Increase vm.boot_pages", zone->uz_name); /* * Now that we've booted reset these users to their real allocator. */ @@ -1785,6 +1785,8 @@ zone_foreach(void (*zfunc)(uma_zone_t)) * zone of zones and zone of kegs are accounted separately. */ #define UMA_BOOT_ZONES 11 +/* Zone of zones and zone of kegs have arbitrary alignment. */ +#define UMA_BOOT_ALIGN 32 static int zsize, ksize; int uma_startup_count(int zones) @@ -1797,26 +1799,36 @@ uma_startup_count(int zones) (sizeof(struct uma_cache) * (mp_maxid + 1)) + (sizeof(struct uma_zone_domain) * vm_ndomains); - /* Memory for the zone of zones and zone of kegs. */ + /* + * Memory for the zone of kegs and its keg, + * and for zone of zones. + */ pages = howmany(roundup(zsize, CACHE_LINE_SIZE) * 2 + roundup(ksize, CACHE_LINE_SIZE), PAGE_SIZE); zones += UMA_BOOT_ZONES; - /* Memory for startup zones, UMA and VM, ... */ + /* Memory for the rest of startup zones, UMA and VM, ... */ if (zsize > UMA_SLAB_SIZE) - pages += zones * howmany(zsize, UMA_SLAB_SIZE); + pages += zones * howmany(roundup2(zsize, UMA_BOOT_ALIGN), + UMA_SLAB_SIZE); else - pages += howmany(zones, UMA_SLAB_SIZE / zsize); + pages += howmany(zones, + UMA_SLAB_SPACE / roundup2(zsize, UMA_BOOT_ALIGN)); - /* ... and their kegs. */ - pages += howmany(zones, UMA_SLAB_SIZE / ksize); + /* ... and their kegs. Note that zone of zones allocates a keg! */ + pages += howmany(zones + 1, + UMA_SLAB_SPACE / roundup2(ksize, UMA_BOOT_ALIGN)); /* - * Take conservative approach that every zone - * is going to allocate hash. + * Most of startup zones are not going to be offpages, that's + * why we use UMA_SLAB_SPACE instead of UMA_SLAB_SIZE in all + * calculations. Some large bucket zones will be offpage, and + * thus will allocate hashes. We take conservative approach + * and assume that all zones may allocate hash. This may give + * us some positive inaccuracy, usually an extra single page. */ - pages += howmany(zones, UMA_SLAB_SIZE / + pages += howmany(zones, UMA_SLAB_SPACE / (sizeof(struct slabhead *) * UMA_HASH_SIZE_INIT)); return (pages); @@ -1856,7 +1868,7 @@ uma_startup(void *mem, int npages) args.uminit = zero_init; args.fini = NULL; args.keg = masterkeg; - args.align = 32 - 1; + args.align = UMA_BOOT_ALIGN - 1; args.flags = UMA_ZFLAG_INTERNAL; zone_ctor(kegs, zsize, &args, M_WAITOK); @@ -1871,7 +1883,7 @@ uma_startup(void *mem, int npages) args.uminit = zero_init; args.fini = NULL; args.keg = NULL; - args.align = 32 - 1; + args.align = UMA_BOOT_ALIGN - 1; args.flags = UMA_ZFLAG_INTERNAL; zone_ctor(zones, zsize, &args, M_WAITOK); Modified: head/sys/vm/uma_int.h ============================================================================== --- head/sys/vm/uma_int.h Wed Feb 7 18:18:33 2018 (r328981) +++ head/sys/vm/uma_int.h Wed Feb 7 18:32:51 2018 (r328982) @@ -138,6 +138,11 @@ #define UMA_MAX_WASTE 10 /* + * Size of memory in a not offpage slab available for actual items. + */ +#define UMA_SLAB_SPACE (UMA_SLAB_SIZE - sizeof(struct uma_slab)) + +/* * I doubt there will be many cases where this is exceeded. This is the initial * size of the hash table for uma_slabs that are managed off page. This hash * does expand by powers of two. Currently it doesn't get smaller. Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Wed Feb 7 18:18:33 2018 (r328981) +++ head/sys/vm/vm_page.c Wed Feb 7 18:32:51 2018 (r328982) @@ -519,7 +519,8 @@ vm_page_startup(vm_offset_t vaddr) /* vmem_startup() calls uma_prealloc(). */ boot_pages += vmem_startup_count(); /* vm_map_startup() calls uma_prealloc(). */ - boot_pages += howmany(MAX_KMAP, UMA_SLAB_SIZE / sizeof(struct vm_map)); + boot_pages += howmany(MAX_KMAP, + UMA_SLAB_SPACE / sizeof(struct vm_map)); /* * Before going fully functional kmem_init() does allocation
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