Getting a page from the fault handler might require poking at some
swap-related states.
These are not in the hot-path of the fault handler so for the moment
just assert that the KERNEL_LOCK() is held or grab it if the function
might be called from an future unlocked path.
ok?
Index: uvm/uvm_swap.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_swap.c,v
retrieving revision 1.147
diff -u -p -r1.147 uvm_swap.c
--- uvm/uvm_swap.c 29 Sep 2020 11:47:41 -0000 1.147
+++ uvm/uvm_swap.c 7 Dec 2020 18:07:03 -0000
@@ -1403,7 +1403,7 @@ uvm_swap_alloc(int *nslots, boolean_t le
/*
* lock data lock, convert slots into blocks, and enter loop
*/
-
+ KERNEL_ASSERT_LOCKED();
ReTry: /* XXXMRG */
LIST_FOREACH(spp, &swap_priority, spi_swappri) {
TAILQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) {
@@ -1449,8 +1449,10 @@ uvm_swapisfull(void)
{
int result;
+ KERNEL_LOCK();
KASSERT(uvmexp.swpgonly <= uvmexp.swpages);
result = (uvmexp.swpgonly == uvmexp.swpages);
+ KERNEL_UNLOCK();
return result;
}
@@ -1465,6 +1467,7 @@ uvm_swap_markbad(int startslot, int nslo
{
struct swapdev *sdp;
+ KERNEL_LOCK();
sdp = swapdrum_getsdp(startslot);
if (sdp != NULL) {
/*
@@ -1475,6 +1478,7 @@ uvm_swap_markbad(int startslot, int nslo
*/
sdp->swd_npgbad += nslots;
}
+ KERNEL_UNLOCK();
}
/*
@@ -1501,7 +1505,7 @@ uvm_swap_free(int startslot, int nslots)
* in the extent, and return. must hold pri lock to do
* lookup and access the extent.
*/
-
+ KERNEL_LOCK();
sdp = swapdrum_getsdp(startslot);
KASSERT(uvmexp.nswapdev >= 1);
KASSERT(sdp != NULL);
@@ -1533,6 +1537,7 @@ uvm_swap_free(int startslot, int nslots)
}
}
#endif /* UVM_SWAP_ENCRYPT */
+ KERNEL_UNLOCK();
}
/*
@@ -1567,6 +1572,7 @@ uvm_swap_get(struct vm_page *page, int s
return VM_PAGER_ERROR;
}
+ KERNEL_LOCK();
/* this page is (about to be) no longer only in swap. */
uvmexp.swpgonly--;
@@ -1577,7 +1583,7 @@ uvm_swap_get(struct vm_page *page, int s
/* oops, the read failed so it really is still only in swap. */
uvmexp.swpgonly++;
}
-
+ KERNEL_UNLOCK();
return (result);
}
@@ -1599,6 +1605,8 @@ uvm_swap_io(struct vm_page **pps, int st
struct swapdev *sdp;
int encrypt = 0;
#endif
+
+ KERNEL_ASSERT_LOCKED();
write = (flags & B_READ) == 0;
async = (flags & B_ASYNC) != 0;
Index: uvm/uvmexp.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvmexp.h,v
retrieving revision 1.6
diff -u -p -r1.6 uvmexp.h
--- uvm/uvmexp.h 1 Dec 2020 13:56:22 -0000 1.6
+++ uvm/uvmexp.h 7 Dec 2020 18:09:06 -0000
@@ -79,9 +79,9 @@ struct uvmexp {
/* swap */
int nswapdev; /* number of configured swap devices in system */
- int swpages; /* number of PAGE_SIZE'ed swap pages */
+ int swpages; /* [K] number of PAGE_SIZE'ed swap pages */
int swpginuse; /* number of swap pages in use */
- int swpgonly; /* number of swap pages in use, not also in RAM */
+ int swpgonly; /* [K] number of swap pages in use, not also in RAM */
int nswget; /* number of swap pages moved from disk to RAM */
int nanon; /* XXX number total of anon's in system */
int unused05; /* formerly nanonneeded */
