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Fix three miscalculations in amount of boot pages:

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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]
This commit is contained in:
glebius 2018-02-07 18:32:51 +00:00
parent cf5b057c5b
commit ed8d237f4f
4 changed files with 33 additions and 14 deletions
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3
sys/kern/subr_vmem.c
View File

@ -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

36
sys/vm/uma_core.c
View File

@ -1102,7 +1102,7 @@ startup_alloc(uma_zone_t zone, vm_size_t bytes, int domain, uint8_t *pflag,
}
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);

5
sys/vm/uma_int.h
View File

@ -137,6 +137,11 @@
/* Max waste percentage before going to off page slab management */
#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

3
sys/vm/vm_page.c
View File

@ -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