Date: Tue, 29 Jan 2013 13:49:58 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r246070 - projects/counters/sys/vm Message-ID: <201301291349.r0TDnww9018710@svn.freebsd.org>
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Author: glebius Date: Tue Jan 29 13:49:58 2013 New Revision: 246070 URL: http://svnweb.freebsd.org/changeset/base/246070 Log: Don't hardcode slab size in UMA_SMALLEST_UNIT and UMA_MAX_WASTE. Instead calculate these values based on keg->uk_slabsize, where it is possible. This means, that on zones with a smaller slab size, like pcpu zones we can go for items smaller than 16 bytes. This allows us to reduce UMA waste for uint64_t pcpu zone by 100%. Modified: projects/counters/sys/vm/uma_core.c projects/counters/sys/vm/uma_int.h Modified: projects/counters/sys/vm/uma_core.c ============================================================================== --- projects/counters/sys/vm/uma_core.c Tue Jan 29 13:49:08 2013 (r246069) +++ projects/counters/sys/vm/uma_core.c Tue Jan 29 13:49:58 2013 (r246070) @@ -1133,21 +1133,7 @@ keg_small_init(uma_keg_t keg) u_int wastedspace; u_int shsize; - KASSERT(keg != NULL, ("Keg is null in keg_small_init")); - rsize = keg->uk_size; - - if (rsize < UMA_SMALLEST_UNIT) - rsize = UMA_SMALLEST_UNIT; - if (rsize & keg->uk_align) - rsize = (rsize & ~keg->uk_align) + (keg->uk_align + 1); - - keg->uk_rsize = rsize; - if (keg->uk_flags & UMA_ZONE_PCPU) { - - KASSERT(keg->uk_rsize < sizeof(struct pcpu), - ("%s: size %u too large", __func__, keg->uk_rsize)); - keg->uk_slabsize = sizeof(struct pcpu); keg->uk_ppera = mp_ncpus/(PAGE_SIZE/sizeof(struct pcpu)); /* Account for remainder. */ @@ -1158,6 +1144,19 @@ keg_small_init(uma_keg_t keg) keg->uk_ppera = 1; } + rsize = keg->uk_size; + + if (rsize & keg->uk_align) + rsize = (rsize & ~keg->uk_align) + (keg->uk_align + 1); + if (rsize < keg->uk_slabsize / 256) + rsize = keg->uk_slabsize / 256; + + keg->uk_rsize = rsize; + + KASSERT((keg->uk_flags & UMA_ZONE_PCPU) == 0 || + keg->uk_rsize < sizeof(struct pcpu), + ("%s: size %u too large", __func__, keg->uk_rsize)); + if (keg->uk_flags & UMA_ZONE_OFFPAGE) { shsize = 0; } else if (keg->uk_flags & UMA_ZONE_REFCNT) { @@ -1169,7 +1168,9 @@ keg_small_init(uma_keg_t keg) } keg->uk_ipers = (keg->uk_slabsize - shsize) / rsize; - KASSERT(keg->uk_ipers != 0, ("keg_small_init: ipers is 0")); + KASSERT(keg->uk_ipers > 0 && keg->uk_ipers <= 255, + ("%s: keg->uk_ipers %u", __func__, keg->uk_ipers)); + memused = keg->uk_ipers * rsize + shsize; wastedspace = keg->uk_slabsize - memused; @@ -1184,18 +1185,18 @@ keg_small_init(uma_keg_t keg) (keg->uk_flags & UMA_ZFLAG_CACHEONLY)) return; - if ((wastedspace >= UMA_MAX_WASTE) && + if ((wastedspace >= keg->uk_slabsize / UMA_MAX_WASTE) && (keg->uk_ipers < (keg->uk_slabsize / keg->uk_rsize))) { keg->uk_ipers = keg->uk_slabsize / keg->uk_rsize; - KASSERT(keg->uk_ipers <= 255, - ("keg_small_init: keg->uk_ipers too high!")); + KASSERT(keg->uk_ipers > 0 && keg->uk_ipers <= 255, + ("%s: keg->uk_ipers %u", __func__, keg->uk_ipers)); #ifdef UMA_DEBUG printf("UMA decided we need offpage slab headers for " "keg: %s, calculated wastedspace = %d, " "maximum wasted space allowed = %d, " "calculated ipers = %d, " "new wasted space = %d\n", keg->uk_name, wastedspace, - UMA_MAX_WASTE, keg->uk_ipers, + keg->uk_slabsize / UMA_MAX_WASTE, keg->uk_ipers, keg->uk_slabsize - keg->uk_ipers * keg->uk_rsize); #endif keg->uk_flags |= UMA_ZONE_OFFPAGE; @@ -1701,7 +1702,8 @@ uma_startup(void *bootmem, int boot_page * that we need to go to offpage slab headers. Or, if we do, * then we trap that condition below and panic in the INVARIANTS case. */ - wsize = UMA_SLAB_SIZE - sizeof(struct uma_slab) - UMA_MAX_WASTE; + wsize = UMA_SLAB_SIZE - sizeof(struct uma_slab) - + (UMA_SLAB_SIZE / UMA_MAX_WASTE); totsize = wsize; objsize = UMA_SMALLEST_UNIT; while (totsize >= wsize) { @@ -1714,7 +1716,8 @@ uma_startup(void *bootmem, int boot_page objsize--; uma_max_ipers = MAX(UMA_SLAB_SIZE / objsize, 64); - wsize = UMA_SLAB_SIZE - sizeof(struct uma_slab_refcnt) - UMA_MAX_WASTE; + wsize = UMA_SLAB_SIZE - sizeof(struct uma_slab_refcnt) - + (UMA_SLAB_SIZE / UMA_MAX_WASTE); totsize = wsize; objsize = UMA_SMALLEST_UNIT; while (totsize >= wsize) { Modified: projects/counters/sys/vm/uma_int.h ============================================================================== --- projects/counters/sys/vm/uma_int.h Tue Jan 29 13:49:08 2013 (r246069) +++ projects/counters/sys/vm/uma_int.h Tue Jan 29 13:49:58 2013 (r246070) @@ -120,8 +120,8 @@ #define UMA_BOOT_PAGES 64 /* Pages allocated for startup */ -/* Max waste before going to off page slab management */ -#define UMA_MAX_WASTE (UMA_SLAB_SIZE / 10) +/* Max waste percentage before going to off page slab management */ +#define UMA_MAX_WASTE 10 /* * I doubt there will be many cases where this is exceeded. This is the initial
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