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vm_fault: Stop specifying VM_ALLOC_ZERO

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Now vm_page_alloc() and friends will unconditionally preserve PG_ZERO,
so there is no point in setting this flag.

Eliminate a local variable and add a comment explaining why we
prioritize the allocation when the process is doomed.

No functional change intended.

Reviewed by:	kib, alc
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32036
This commit is contained in:
Mark Johnston 2021-10-19 20:27:23 -04:00
parent 6d3c78d970
commit b801c79dda
1 changed files with 10 additions and 10 deletions
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20
sys/vm/vm_fault.c
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@ -1113,7 +1113,6 @@ static int
vm_fault_allocate(struct faultstate *fs)
{
struct domainset *dset;
int alloc_req;
int rv;
if ((fs->object->flags & OBJ_SIZEVNLOCK) != 0) {
@ -1150,9 +1149,14 @@ vm_fault_allocate(struct faultstate *fs)
/*
* Allocate a new page for this object/offset pair.
*
* Unlocked read of the p_flag is harmless. At worst, the P_KILLED
* might be not observed there, and allocation can fail, causing
* restart and new reading of the p_flag.
* If the process has a fatal signal pending, prioritize the allocation
* with the expectation that the process will exit shortly and free some
* pages. In particular, the signal may have been posted by the page
* daemon in an attempt to resolve an out-of-memory condition.
*
* The unlocked read of the p_flag is harmless. At worst, the P_KILLED
* might be not observed here, and allocation fails, causing a restart
* and new reading of the p_flag.
*/
dset = fs->object->domain.dr_policy;
if (dset == NULL)
@ -1161,12 +1165,8 @@ vm_fault_allocate(struct faultstate *fs)
#if VM_NRESERVLEVEL > 0
vm_object_color(fs->object, atop(fs->vaddr) - fs->pindex);
#endif
alloc_req = P_KILLED(curproc) ?
VM_ALLOC_SYSTEM : VM_ALLOC_NORMAL;
if (fs->object->type != OBJT_VNODE &&
fs->object->backing_object == NULL)
alloc_req |= VM_ALLOC_ZERO;
fs->m = vm_page_alloc(fs->object, fs->pindex, alloc_req);
fs->m = vm_page_alloc(fs->object, fs->pindex,
P_KILLED(curproc) ? VM_ALLOC_SYSTEM : 0);
}
if (fs->m == NULL) {
if (vm_fault_allocate_oom(fs))