ilo-pona/xv6-65oo2
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handle another out-of-memory in fork(). the policy here is not consistent,

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since other calls (e.g. exec()) panic on out of memory.
This commit is contained in:
Robert Morris 2020-08-13 10:22:07 -04:00
parent 4c22c54480
commit adee82c3e7
3 changed files with 10 additions and 3 deletions
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2
kernel/proc.c
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@ -161,6 +161,8 @@ proc_pagetable(struct proc *p)
// An empty page table. // An empty page table.
pagetable = uvmcreate(); pagetable = uvmcreate();
if(pagetable == 0)
return 0;
// map the trampoline code (for system call return) // map the trampoline code (for system call return)
// at the highest user virtual address. // at the highest user virtual address.

3
kernel/vm.c
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@ -195,13 +195,14 @@ uvmunmap(pagetable_t pagetable, uint64 va, uint64 npages, int do_free)
} }
// create an empty user page table. // create an empty user page table.
// returns 0 if out of memory.
pagetable_t pagetable_t
uvmcreate() uvmcreate()
{ {
pagetable_t pagetable; pagetable_t pagetable;
pagetable = (pagetable_t) kalloc(); pagetable = (pagetable_t) kalloc();
if(pagetable == 0) if(pagetable == 0)
panic("uvmcreate: out of memory"); return 0;
memset(pagetable, 0, PGSIZE); memset(pagetable, 0, PGSIZE);
return pagetable; return pagetable;
} }

8
user/usertests.c
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@ -2507,6 +2507,8 @@ main(int argc, char *argv[])
if(argc == 2 && strcmp(argv[1], "-c") == 0){ if(argc == 2 && strcmp(argv[1], "-c") == 0){
continuous = 1; continuous = 1;
} else if(argc == 2 && strcmp(argv[1], "-C") == 0){
continuous = 2;
} else if(argc == 2 && argv[1][0] != '-'){ } else if(argc == 2 && argv[1][0] != '-'){
justone = argv[1]; justone = argv[1];
} else if(argc > 1){ } else if(argc > 1){
@ -2589,12 +2591,14 @@ main(int argc, char *argv[])
} }
if(fail){ if(fail){
printf("SOME TESTS FAILED\n"); printf("SOME TESTS FAILED\n");
exit(1); if(continuous != 2)
exit(1);
} }
int free1 = countfree(); int free1 = countfree();
if(free1 < free0){ if(free1 < free0){
printf("FAILED -- lost some free pages\n"); printf("FAILED -- lost some free pages\n");
exit(1); if(continuous != 2)
exit(1);
} }
} }
} }