Date: Thu, 1 Jun 2017 18:26:57 +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: r319448 - head/sys/vm Message-ID: <201706011826.v51IQvFx070487@repo.freebsd.org>
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Author: glebius Date: Thu Jun 1 18:26:57 2017 New Revision: 319448 URL: https://svnweb.freebsd.org/changeset/base/319448 Log: Simplify boot pages management in UMA. It is simply a contigous virtual memory pointer and number of pages. There is no need to build a linked list here. Just increment pointer and decrement counter. The only functional difference to old allocator is that before we gave pages from topmost and down to lowest, and now we give them in normal ascending order. While here remove padalign from a mutex that is unused at runtime. Reviewed by: alc Modified: head/sys/vm/uma_core.c Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Thu Jun 1 17:07:13 2017 (r319447) +++ head/sys/vm/uma_core.c Thu Jun 1 18:26:57 2017 (r319448) @@ -140,13 +140,16 @@ static LIST_HEAD(,uma_zone) uma_cachezones = /* This RW lock protects the keg list */ static struct rwlock_padalign uma_rwlock; -/* Linked list of boot time pages */ -static LIST_HEAD(,uma_slab) uma_boot_pages = - LIST_HEAD_INITIALIZER(uma_boot_pages); +/* + * Pointer and counter to pool of pages, that is preallocated at + * startup to bootstrap UMA. Early zones continue to use the pool + * until it is depleted, so allocations may happen after boot, thus + * we need a mutex to protect it. + */ +static char *bootmem; +static int boot_pages; +static struct mtx uma_boot_pages_mtx; -/* This mutex protects the boot time pages list */ -static struct mtx_padalign uma_boot_pages_mtx; - static struct sx uma_drain_lock; /* Is the VM done starting up? */ @@ -1034,36 +1037,24 @@ static void * startup_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *pflag, int wait) { uma_keg_t keg; - uma_slab_t tmps; - int pages, check_pages; + void *mem; + int pages; keg = zone_first_keg(zone); pages = howmany(bytes, PAGE_SIZE); - check_pages = pages - 1; KASSERT(pages > 0, ("startup_alloc can't reserve 0 pages\n")); /* * Check our small startup cache to see if it has pages remaining. */ mtx_lock(&uma_boot_pages_mtx); - - /* First check if we have enough room. */ - tmps = LIST_FIRST(&uma_boot_pages); - while (tmps != NULL && check_pages-- > 0) - tmps = LIST_NEXT(tmps, us_link); - if (tmps != NULL) { - /* - * It's ok to lose tmps references. The last one will - * have tmps->us_data pointing to the start address of - * "pages" contiguous pages of memory. - */ - while (pages-- > 0) { - tmps = LIST_FIRST(&uma_boot_pages); - LIST_REMOVE(tmps, us_link); - } + if (pages <= boot_pages) { + mem = bootmem; + boot_pages -= pages; + bootmem += pages * PAGE_SIZE; mtx_unlock(&uma_boot_pages_mtx); - *pflag = tmps->us_flags; - return (tmps->us_data); + *pflag = UMA_SLAB_BOOT; + return (mem); } mtx_unlock(&uma_boot_pages_mtx); if (booted < UMA_STARTUP2) @@ -1748,11 +1739,9 @@ zone_foreach(void (*zfunc)(uma_zone_t)) /* Public functions */ /* See uma.h */ void -uma_startup(void *bootmem, int boot_pages) +uma_startup(void *mem, int npages) { struct uma_zctor_args args; - uma_slab_t slab; - int i; #ifdef UMA_DEBUG printf("Creating uma keg headers zone and keg.\n"); @@ -1773,16 +1762,9 @@ uma_startup(void *bootmem, int boot_pages) /* The initial zone has no Per cpu queues so it's smaller */ zone_ctor(kegs, sizeof(struct uma_zone), &args, M_WAITOK); -#ifdef UMA_DEBUG - printf("Filling boot free list.\n"); -#endif - for (i = 0; i < boot_pages; i++) { - slab = (uma_slab_t)((uint8_t *)bootmem + (i * UMA_SLAB_SIZE)); - slab->us_data = (uint8_t *)slab; - slab->us_flags = UMA_SLAB_BOOT; - LIST_INSERT_HEAD(&uma_boot_pages, slab, us_link); - } mtx_init(&uma_boot_pages_mtx, "UMA boot pages", NULL, MTX_DEF); + bootmem = mem; + boot_pages = npages; #ifdef UMA_DEBUG printf("Creating uma zone headers zone and keg.\n");
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