From e6ee97803e2e4bc2318d05d375cfafd22d4bc79c Mon Sep 17 00:00:00 2001 From: alfred Date: Wed, 18 Apr 2001 20:24:16 +0000 Subject: Protect pager object creation with sx locks. Protect pager object list manipulation with a mutex. It doesn't look possible to combine them under a single sx lock because creation may block and we can't have the object list manipulation block on anything other than a mutex because of interrupt requests. --- sys/vm/device_pager.c | 25 ++++++++++++++----------- sys/vm/phys_pager.c | 28 ++++++++++++++++------------ sys/vm/swap_pager.c | 23 +++++++++++++---------- 3 files changed, 43 insertions(+), 33 deletions(-) diff --git a/sys/vm/device_pager.c b/sys/vm/device_pager.c index 85cad81..7d7480c 100644 --- a/sys/vm/device_pager.c +++ b/sys/vm/device_pager.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -62,6 +63,11 @@ static boolean_t dev_pager_haspage __P((vm_object_t, vm_pindex_t, int *, /* list of device pager objects */ static struct pagerlst dev_pager_object_list; +/* protect against object creation */ +static struct sx dev_pager_sx; +/* protect list manipulation */ +static struct mtx dev_pager_mtx; + static vm_zone_t fakepg_zone; static struct vm_zone fakepg_zone_store; @@ -69,8 +75,6 @@ static struct vm_zone fakepg_zone_store; static vm_page_t dev_pager_getfake __P((vm_offset_t)); static void dev_pager_putfake __P((vm_page_t)); -static int dev_pager_alloc_lock, dev_pager_alloc_lock_want; - struct pagerops devicepagerops = { dev_pager_init, dev_pager_alloc, @@ -85,6 +89,8 @@ static void dev_pager_init() { TAILQ_INIT(&dev_pager_object_list); + sx_init(&dev_pager_sx, "dev_pager create"); + mtx_init(&dev_pager_mtx, "dev_pager list", MTX_DEF); fakepg_zone = &fakepg_zone_store; zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2); } @@ -130,12 +136,7 @@ dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t fo /* * Lock to prevent object creation race condition. */ - while (dev_pager_alloc_lock) { - dev_pager_alloc_lock_want++; - tsleep(&dev_pager_alloc_lock, PVM, "dvpall", 0); - dev_pager_alloc_lock_want--; - } - dev_pager_alloc_lock = 1; + sx_xlock(&dev_pager_sx); /* * Look up pager, creating as necessary. @@ -149,7 +150,9 @@ dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t fo OFF_TO_IDX(foff + size)); object->handle = handle; TAILQ_INIT(&object->un_pager.devp.devp_pglist); + mtx_lock(&dev_pager_mtx); TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); + mtx_unlock(&dev_pager_mtx); } else { /* * Gain a reference to the object. @@ -159,9 +162,7 @@ dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t fo object->size = OFF_TO_IDX(foff + size); } - dev_pager_alloc_lock = 0; - if (dev_pager_alloc_lock_want) - wakeup(&dev_pager_alloc_lock); + sx_xunlock(&dev_pager_sx); return (object); } @@ -172,7 +173,9 @@ dev_pager_dealloc(object) { vm_page_t m; + mtx_lock(&dev_pager_mtx); TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); + mtx_unlock(&dev_pager_mtx); /* * Free up our fake pages. */ diff --git a/sys/vm/phys_pager.c b/sys/vm/phys_pager.c index 6e710b2..5a6aca5 100644 --- a/sys/vm/phys_pager.c +++ b/sys/vm/phys_pager.c @@ -29,8 +29,10 @@ #include #include #include +#include #include #include +#include #include #include @@ -38,16 +40,20 @@ #include #include +/* prevent concurrant creation races */ +static struct sx phys_pager_sx; /* list of device pager objects */ static struct pagerlst phys_pager_object_list; - -static int phys_pager_alloc_lock, phys_pager_alloc_lock_want; +/* protect access to phys_pager_object_list */ +static struct mtx phys_pager_mtx; static void phys_pager_init(void) { TAILQ_INIT(&phys_pager_object_list); + sx_init(&phys_pager_sx, "phys_pager create"); + mtx_init(&phys_pager_mtx, "phys_pager list", MTX_DEF); } static vm_object_t @@ -68,12 +74,7 @@ phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, /* * Lock to prevent object creation race condition. */ - while (phys_pager_alloc_lock) { - phys_pager_alloc_lock_want++; - tsleep(&phys_pager_alloc_lock, PVM, "ppall", 0); - phys_pager_alloc_lock_want--; - } - phys_pager_alloc_lock = 1; + sx_xlock(&phys_pager_sx); /* * Look up pager, creating as necessary. @@ -86,8 +87,10 @@ phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, object = vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(foff + size)); object->handle = handle; + mtx_lock(&phys_pager_mtx); TAILQ_INSERT_TAIL(&phys_pager_object_list, object, pager_object_list); + mtx_unlock(&phys_pager_mtx); } else { /* * Gain a reference to the object. @@ -96,9 +99,7 @@ phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, if (OFF_TO_IDX(foff + size) > object->size) object->size = OFF_TO_IDX(foff + size); } - phys_pager_alloc_lock = 0; - if (phys_pager_alloc_lock_want) - wakeup(&phys_pager_alloc_lock); + sx_xunlock(&phys_pager_sx); } else { object = vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(foff + size)); @@ -111,8 +112,11 @@ static void phys_pager_dealloc(vm_object_t object) { - if (object->handle != NULL) + if (object->handle != NULL) { + mtx_lock(&phys_pager_mtx); TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); + mtx_unlock(&phys_pager_mtx); + } } static int diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c index aedae78..aa2cb52 100644 --- a/sys/vm/swap_pager.c +++ b/sys/vm/swap_pager.c @@ -80,6 +80,7 @@ #include #include #include +#include #include #ifndef MAX_PAGEOUT_CLUSTER @@ -118,7 +119,6 @@ static int nsw_wcount_sync; /* limit write buffers / synchronous */ static int nsw_wcount_async; /* limit write buffers / asynchronous */ static int nsw_wcount_async_max;/* assigned maximum */ static int nsw_cluster_max; /* maximum VOP I/O allowed */ -static int sw_alloc_interlock; /* swap pager allocation interlock */ struct blist *swapblist; static struct swblock **swhash; @@ -145,6 +145,8 @@ SYSCTL_INT(_vm, OID_AUTO, swap_async_max, #define NOBJLIST(handle) \ (&swap_pager_object_list[((int)(intptr_t)handle >> 4) & (NOBJLISTS-1)]) +static struct sx sw_alloc_sx; /* prevent concurrant creation */ +static struct mtx sw_alloc_mtx; /* protect list manipulation */ static struct pagerlst swap_pager_object_list[NOBJLISTS]; struct pagerlst swap_pager_un_object_list; vm_zone_t swap_zone; @@ -262,6 +264,8 @@ swap_pager_init() for (i = 0; i < NOBJLISTS; ++i) TAILQ_INIT(&swap_pager_object_list[i]); TAILQ_INIT(&swap_pager_un_object_list); + sx_init(&sw_alloc_sx, "swap_pager create"); + mtx_init(&sw_alloc_mtx, "swap_pager list", MTX_DEF); /* * Device Stripe, in PAGE_SIZE'd blocks @@ -385,11 +389,7 @@ swap_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, * of the handle. */ - while (sw_alloc_interlock) { - sw_alloc_interlock = -1; - tsleep(&sw_alloc_interlock, PVM, "swpalc", 0); - } - sw_alloc_interlock = 1; + sx_xlock(&sw_alloc_sx); object = vm_pager_object_lookup(NOBJLIST(handle), handle); @@ -403,10 +403,7 @@ swap_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, swp_pager_meta_build(object, 0, SWAPBLK_NONE); } - if (sw_alloc_interlock < 0) - wakeup(&sw_alloc_interlock); - - sw_alloc_interlock = 0; + sx_xunlock(&sw_alloc_sx); } else { object = vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(offset + PAGE_MASK + size)); @@ -441,11 +438,13 @@ swap_pager_dealloc(object) * pageout completion. */ + mtx_lock(&sw_alloc_mtx); if (object->handle == NULL) { TAILQ_REMOVE(&swap_pager_un_object_list, object, pager_object_list); } else { TAILQ_REMOVE(NOBJLIST(object->handle), object, pager_object_list); } + mtx_unlock(&sw_alloc_mtx); vm_object_pip_wait(object, "swpdea"); @@ -642,6 +641,7 @@ swap_pager_copy(srcobject, dstobject, offset, destroysource) */ if (destroysource) { + mtx_lock(&sw_alloc_mtx); if (srcobject->handle == NULL) { TAILQ_REMOVE( &swap_pager_un_object_list, @@ -655,6 +655,7 @@ swap_pager_copy(srcobject, dstobject, offset, destroysource) pager_object_list ); } + mtx_unlock(&sw_alloc_mtx); } /* @@ -1753,6 +1754,7 @@ swp_pager_meta_build( object->type = OBJT_SWAP; object->un_pager.swp.swp_bcount = 0; + mtx_lock(&sw_alloc_mtx); if (object->handle != NULL) { TAILQ_INSERT_TAIL( NOBJLIST(object->handle), @@ -1766,6 +1768,7 @@ swp_pager_meta_build( pager_object_list ); } + mtx_unlock(&sw_alloc_mtx); } /* -- cgit v1.1