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vm_pager: add method to veto page allocation

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Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D37097
This commit is contained in:
Konstantin Belousov 2022-10-20 16:15:46 +03:00
parent d537d1f12e
commit ec201dddfb
4 changed files with 20 additions and 0 deletions
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4
sys/vm/vm_fault.c
View File

@ -1212,6 +1212,10 @@ vm_fault_allocate(struct faultstate *fs)
#if VM_NRESERVLEVEL > 0
vm_object_color(fs->object, atop(fs->vaddr) - fs->pindex);
#endif
if (!vm_pager_can_alloc_page(fs->object, fs->pindex)) {
unlock_and_deallocate(fs);
return (FAULT_FAILURE);
}
fs->m = vm_page_alloc(fs->object, fs->pindex,
P_KILLED(curproc) ? VM_ALLOC_SYSTEM : 0);
}

4
sys/vm/vm_page.c
View File

@ -2027,6 +2027,8 @@ vm_page_alloc_domain_after(vm_object_t object, vm_pindex_t pindex, int domain,
flags = 0;
m = NULL;
if (!vm_pager_can_alloc_page(object, pindex))
return (NULL);
again:
#if VM_NRESERVLEVEL > 0
/*
@ -4698,6 +4700,8 @@ vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex, int al
*mp = NULL;
return (VM_PAGER_FAIL);
} else if ((m = vm_page_alloc(object, pindex, pflags)) == NULL) {
if (!vm_pager_can_alloc_page(object, pindex))
return (VM_PAGER_AGAIN);
goto retrylookup;
}

1
sys/vm/vm_pager.c
View File

@ -432,6 +432,7 @@ vm_pager_alloc_dyn_type(struct pagerops *ops, int base_type)
FIX(freespace);
FIX(page_inserted);
FIX(page_removed);
FIX(can_alloc_page);
#undef FIX
}
pagertab[res] = ops; /* XXXKIB should be rel, but acq is too much */

11
sys/vm/vm_pager.h
View File

@ -71,6 +71,7 @@ typedef void pgo_freespace_t(vm_object_t object, vm_pindex_t start,
vm_size_t size);
typedef void pgo_page_inserted_t(vm_object_t object, vm_page_t m);
typedef void pgo_page_removed_t(vm_object_t object, vm_page_t m);
typedef boolean_t pgo_can_alloc_page_t(vm_object_t object, vm_pindex_t pindex);
struct pagerops {
int pgo_kvme_type;
@ -91,6 +92,7 @@ struct pagerops {
pgo_freespace_t *pgo_freespace;
pgo_page_inserted_t *pgo_page_inserted;
pgo_page_removed_t *pgo_page_removed;
pgo_can_alloc_page_t *pgo_can_alloc_page;
};
extern const struct pagerops defaultpagerops;
@ -273,6 +275,15 @@ vm_pager_page_removed(vm_object_t object, vm_page_t m)
method(object, m);
}
static __inline bool
vm_pager_can_alloc_page(vm_object_t object, vm_pindex_t pindex)
{
pgo_can_alloc_page_t *method;
method = pagertab[object->type]->pgo_can_alloc_page;
return (method != NULL ? method(object, pindex) : true);
}
int vm_pager_alloc_dyn_type(struct pagerops *ops, int base_type);
void vm_pager_free_dyn_type(objtype_t type);