uma: split slabzone into two sizes
By allowing more items per slab, we can improve memory efficiency for small allocs. If we were just to increase the bitmap size of the slabzone, we would then waste slabzone memory. So, split slabzone into two zones, one especially for 8-byte allocs (512 per slab). The practical effect should be reduced memory usage for counter(9). Reviewed by: jeff, markj Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D23149
This commit is contained in:
Ryan Libby
parent
51871224c0
commit
9b8db4d0a0
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=356717
@ -42,7 +42,7 @@
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#include <sys/malloc.h> /* For M_* */
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/* User visible parameters */
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#define UMA_SMALLEST_UNIT (PAGE_SIZE / 256) /* Smallest item allocated */
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#define UMA_SMALLEST_UNIT 8 /* Smallest item allocated */
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/* Types and type defs */
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@ -107,8 +107,21 @@ __FBSDID("$FreeBSD$");
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static uma_zone_t kegs;
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static uma_zone_t zones;
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/* This is the zone from which all offpage uma_slab_ts are allocated. */
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static uma_zone_t slabzone;
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/*
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* These are the two zones from which all offpage uma_slab_ts are allocated.
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*
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* One zone is for slab headers that can represent a larger number of items,
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* making the slabs themselves more efficient, and the other zone is for
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* headers that are smaller and represent fewer items, making the headers more
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* efficient.
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*/
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#define SLABZONE_SIZE(setsize) \
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(sizeof(struct uma_hash_slab) + BITSET_SIZE(setsize) * SLAB_BITSETS)
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#define SLABZONE0_SETSIZE (PAGE_SIZE / 16)
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#define SLABZONE1_SETSIZE SLAB_MAX_SETSIZE
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#define SLABZONE0_SIZE SLABZONE_SIZE(SLABZONE0_SETSIZE)
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#define SLABZONE1_SIZE SLABZONE_SIZE(SLABZONE1_SETSIZE)
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static uma_zone_t slabzones[2];
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/*
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* The initial hash tables come out of this zone so they can be allocated
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@ -340,6 +353,16 @@ static int zone_warnings = 1;
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SYSCTL_INT(_vm, OID_AUTO, zone_warnings, CTLFLAG_RWTUN, &zone_warnings, 0,
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"Warn when UMA zones becomes full");
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/*
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* Select the slab zone for an offpage slab with the given maximum item count.
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*/
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static inline uma_zone_t
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slabzone(int ipers)
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{
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return (slabzones[ipers > SLABZONE0_SETSIZE]);
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}
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/*
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* This routine checks to see whether or not it's safe to enable buckets.
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*/
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@ -1169,7 +1192,8 @@ keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
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keg->uk_fini(slab_item(slab, keg, i), keg->uk_size);
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}
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if (keg->uk_flags & UMA_ZFLAG_OFFPAGE)
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zone_free_item(keg->uk_slabzone, slab, NULL, SKIP_NONE);
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zone_free_item(slabzone(keg->uk_ipers), slab_tohashslab(slab),
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NULL, SKIP_NONE);
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keg->uk_freef(mem, PAGE_SIZE * keg->uk_ppera, flags);
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uma_total_dec(PAGE_SIZE * keg->uk_ppera);
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}
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@ -1302,9 +1326,12 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
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slab = NULL;
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mem = NULL;
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if (keg->uk_flags & UMA_ZFLAG_OFFPAGE) {
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slab = zone_alloc_item(keg->uk_slabzone, NULL, domain, aflags);
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if (slab == NULL)
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uma_hash_slab_t hslab;
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hslab = zone_alloc_item(slabzone(keg->uk_ipers), NULL,
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domain, aflags);
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if (hslab == NULL)
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goto fail;
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slab = &hslab->uhs_slab;
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}
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/*
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@ -1327,7 +1354,8 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
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mem = allocf(zone, size, domain, &sflags, aflags);
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if (mem == NULL) {
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if (keg->uk_flags & UMA_ZFLAG_OFFPAGE)
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zone_free_item(keg->uk_slabzone, slab, NULL, SKIP_NONE);
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zone_free_item(slabzone(keg->uk_ipers),
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slab_tohashslab(slab), NULL, SKIP_NONE);
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goto fail;
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}
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uma_total_inc(size);
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@ -1340,7 +1368,7 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
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if (!(keg->uk_flags & UMA_ZFLAG_OFFPAGE))
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slab = (uma_slab_t )(mem + keg->uk_pgoff);
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else
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((uma_hash_slab_t)slab)->uhs_data = mem;
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slab_tohashslab(slab)->uhs_data = mem;
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if (keg->uk_flags & UMA_ZFLAG_VTOSLAB)
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for (i = 0; i < keg->uk_ppera; i++)
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@ -1769,7 +1797,7 @@ keg_layout(uma_keg_t keg)
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* alignment. If the requested size is smaller than we have
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* allocation bits for we round it up.
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*/
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rsize = MAX(keg->uk_size, UMA_SLAB_SIZE / SLAB_MAX_SETSIZE);
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rsize = MAX(keg->uk_size, UMA_SMALLEST_UNIT);
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rsize = roundup2(rsize, alignsize);
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if ((keg->uk_flags & UMA_ZONE_PCPU) != 0) {
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@ -1837,7 +1865,7 @@ keg_layout(uma_keg_t keg)
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eff = UMA_FRAC_FIXPT(ipers * rsize, slabsize);
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ipers_offpage = slab_ipers_hdr(keg->uk_size, rsize, slabsize, false);
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eff_offpage = UMA_FRAC_FIXPT(ipers_offpage * rsize,
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slabsize + slab_sizeof(SLAB_MAX_SETSIZE));
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slabsize + slabzone(ipers_offpage)->uz_keg->uk_rsize);
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if (ipers == 0 || (eff < UMA_MIN_EFF && eff < eff_offpage)) {
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CTR5(KTR_UMA, "UMA decided we need offpage slab headers for "
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"keg: %s(%p), minimum efficiency allowed = %u%%, "
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@ -1895,7 +1923,6 @@ keg_ctor(void *mem, int size, void *udata, int flags)
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keg->uk_align = arg->align;
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keg->uk_reserve = 0;
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keg->uk_flags = arg->flags;
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keg->uk_slabzone = NULL;
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/*
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* We use a global round-robin policy by default. Zones with
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@ -1941,9 +1968,6 @@ keg_ctor(void *mem, int size, void *udata, int flags)
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keg->uk_flags |= UMA_ZONE_ROUNDROBIN;
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#endif
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if (keg->uk_flags & UMA_ZFLAG_OFFPAGE)
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keg->uk_slabzone = slabzone;
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/*
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* If we haven't booted yet we need allocations to go through the
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* startup cache until the vm is ready.
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@ -2489,7 +2513,7 @@ zone_foreach(void (*zfunc)(uma_zone_t, void *arg), void *arg)
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* which consist of the UMA Slabs, UMA Hash and 9 Bucket zones. The
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* zone of zones and zone of kegs are accounted separately.
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*/
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#define UMA_BOOT_ZONES 11
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#define UMA_BOOT_ZONES 12
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static int zsize, ksize;
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int
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uma_startup_count(int vm_zones)
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@ -2607,8 +2631,10 @@ uma_startup(void *mem, int npages)
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args.flags = UMA_ZFLAG_INTERNAL;
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zone_ctor(zones, zsize, &args, M_WAITOK);
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/* Now make a zone for slab headers */
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slabzone = uma_zcreate("UMA Slabs", sizeof(struct uma_hash_slab),
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/* Now make zones for slab headers */
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slabzones[0] = uma_zcreate("UMA Slabs 0", SLABZONE0_SIZE,
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NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZFLAG_INTERNAL);
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slabzones[1] = uma_zcreate("UMA Slabs 1", SLABZONE1_SIZE,
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NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZFLAG_INTERNAL);
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hashzone = uma_zcreate("UMA Hash",
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@ -3293,7 +3319,7 @@ slab_alloc_item(uma_keg_t keg, uma_slab_t slab)
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{
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uma_domain_t dom;
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void *item;
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uint8_t freei;
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int freei;
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KEG_LOCK_ASSERT(keg, slab->us_domain);
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@ -3975,7 +4001,7 @@ slab_free_item(uma_zone_t zone, uma_slab_t slab, void *item)
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{
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uma_keg_t keg;
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uma_domain_t dom;
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uint8_t freei;
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int freei;
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keg = zone->uz_keg;
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KEG_LOCK_ASSERT(keg, slab->us_domain);
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@ -4391,7 +4417,8 @@ uma_reclaim(int req)
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* we visit again so that we can free pages that are empty once other
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* zones are drained. We have to do the same for buckets.
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*/
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zone_drain(slabzone, NULL);
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zone_drain(slabzones[0], NULL);
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zone_drain(slabzones[1], NULL);
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bucket_zone_drain();
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sx_xunlock(&uma_reclaim_lock);
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}
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@ -4763,7 +4790,7 @@ sysctl_handle_uma_slab_efficiency(SYSCTL_HANDLER_ARGS)
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total = keg->uk_ppera * PAGE_SIZE;
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if ((keg->uk_flags & UMA_ZFLAG_OFFPAGE) != 0)
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total += slab_sizeof(SLAB_MAX_SETSIZE);
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total += slabzone(keg->uk_ipers)->uz_keg->uk_rsize;
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/*
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* We consider the client's requested size and alignment here, not the
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* real size determination uk_rsize, because we also adjust the real
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@ -213,10 +213,10 @@
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#define UMA_HASH_INSERT(h, s, mem) \
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LIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \
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(mem))], (uma_hash_slab_t)(s), uhs_hlink)
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(mem))], slab_tohashslab(s), uhs_hlink)
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#define UMA_HASH_REMOVE(h, s) \
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LIST_REMOVE((uma_hash_slab_t)(s), uhs_hlink)
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LIST_REMOVE(slab_tohashslab(s), uhs_hlink)
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LIST_HEAD(slabhashhead, uma_hash_slab);
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@ -351,7 +351,6 @@ struct uma_keg {
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u_long uk_offset; /* Next free offset from base KVA */
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vm_offset_t uk_kva; /* Zone base KVA */
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uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */
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uint32_t uk_pgoff; /* Offset to uma_slab struct */
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uint16_t uk_ppera; /* pages per allocation from backend */
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@ -377,7 +376,6 @@ typedef struct uma_keg * uma_keg_t;
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*/
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#define SLAB_MAX_SETSIZE (PAGE_SIZE / UMA_SMALLEST_UNIT)
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#define SLAB_MIN_SETSIZE _BITSET_BITS
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BITSET_DEFINE(slabbits, SLAB_MAX_SETSIZE);
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BITSET_DEFINE(noslabbits, 0);
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/*
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@ -419,17 +417,20 @@ int slab_ipers(size_t size, int align);
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* HASH and OFFPAGE zones.
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*/
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struct uma_hash_slab {
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struct uma_slab uhs_slab; /* Must be first. */
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struct slabbits uhs_bits1; /* Must be second. */
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#ifdef INVARIANTS
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struct slabbits uhs_bits2; /* Must be third. */
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#endif
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LIST_ENTRY(uma_hash_slab) uhs_hlink; /* Link for hash table */
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uint8_t *uhs_data; /* First item */
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struct uma_slab uhs_slab; /* Must be last. */
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};
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typedef struct uma_hash_slab * uma_hash_slab_t;
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static inline uma_hash_slab_t
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slab_tohashslab(uma_slab_t slab)
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{
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return (__containerof(slab, struct uma_hash_slab, uhs_slab));
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}
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static inline void *
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slab_data(uma_slab_t slab, uma_keg_t keg)
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{
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@ -437,7 +438,7 @@ slab_data(uma_slab_t slab, uma_keg_t keg)
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if ((keg->uk_flags & UMA_ZFLAG_OFFPAGE) == 0)
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return ((void *)((uintptr_t)slab - keg->uk_pgoff));
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else
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return (((uma_hash_slab_t)slab)->uhs_data);
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return (slab_tohashslab(slab)->uhs_data);
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}
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static inline void *
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