thmap_create: Test allocation, not relocation, for null. #14
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Adapt test so it never returns zero on success. fix rmind#13
netbsd-srcmastr
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Oct 17, 2023
THMAP_GETPTR may return nonnull even though alloc returned zero. Note that this failure branch is not actually appropriate; thmap_create should not fail. We really need to pass KM_SLEEP through in this call site even though there are other call sites for which KM_NOSLEEP is appropriate. Adapted from: rmind/thmap#14 PR kern/57666 rmind/thmap#13 XXX pullup-10 XXX pullup-9
rmind
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Oct 17, 2023
| @@ -242,13 +242,13 @@ alloc_test_wrapper(size_t len) | |||
| uintptr_t p = space_allocated; | |||
| space_allocated += roundup2(len, sizeof(void *)); | |||
| assert(space_allocated <= sizeof(space)); | |||
| return p; | |||
| return p + 4; | |||
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Can you please define something like static const unsigned space_off = 4; after space_allocated and use the constant? Thanks.
rmind
reviewed
Oct 17, 2023
| @@ -894,11 +894,11 @@ thmap_create(uintptr_t baseptr, const thmap_ops_t *ops, unsigned flags) | |||
| if ((thmap->flags & THMAP_SETROOT) == 0) { | |||
| /* Allocate the root level. */ | |||
| root = thmap->ops->alloc(THMAP_ROOT_LEN); | |||
| thmap->root = THMAP_GETPTR(thmap, root); | |||
| if (!thmap->root) { | |||
| if (!root) { | |||
netbsd-srcmastr
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Oct 20, 2023
sys/kern/subr_thmap.c: revision 1.14 sys/kern/subr_thmap.c: revision 1.15 thmap(9): Test alloc failure, not THMAP_GETPTR failure. THMAP_GETPTR may return nonnull even though alloc returned zero. Note that this failure branch is not actually appropriate; thmap_create should not fail. We really need to pass KM_SLEEP through in this call site even though there are other call sites for which KM_NOSLEEP is appropriate. Adapted from: rmind/thmap#14 PR kern/57666 rmind/thmap#13 thmap(9): Preallocate GC list storage for thmap_del. thmap_del can't fail, and it is used in places in npf where sleeping is forbidden, so it can't rely on allocating memory either. Instead of having thmap_del allocate memory on the fly for each object to defer freeing until thmap_gc, arrange to have thmap(9) preallocate the same storage when allocating all the objects in the first place, with a GC header. This is suboptimal for memory usage, especially on insertion- and lookup-heavy but deletion-light workloads, but it's not clear rmind's alternative (https://github.com/rmind/thmap/tree/thmap_del_mem_fail) is ready to use yet, so we'll go with this for correctness. PR kern/57208 rmind/npf#129
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sys/kern/subr_thmap.c: revision 1.14 sys/kern/subr_thmap.c: revision 1.15 thmap(9): Test alloc failure, not THMAP_GETPTR failure. THMAP_GETPTR may return nonnull even though alloc returned zero. Note that this failure branch is not actually appropriate; thmap_create should not fail. We really need to pass KM_SLEEP through in this call site even though there are other call sites for which KM_NOSLEEP is appropriate. Adapted from: rmind/thmap#14 PR kern/57666 rmind/thmap#13 thmap(9): Preallocate GC list storage for thmap_del. thmap_del can't fail, and it is used in places in npf where sleeping is forbidden, so it can't rely on allocating memory either. Instead of having thmap_del allocate memory on the fly for each object to defer freeing until thmap_gc, arrange to have thmap(9) preallocate the same storage when allocating all the objects in the first place, with a GC header. This is suboptimal for memory usage, especially on insertion- and lookup-heavy but deletion-light workloads, but it's not clear rmind's alternative (https://github.com/rmind/thmap/tree/thmap_del_mem_fail) is ready to use yet, so we'll go with this for correctness. PR kern/57208 rmind/npf#129
rokuyama
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Oct 26, 2023
THMAP_GETPTR may return nonnull even though alloc returned zero. Note that this failure branch is not actually appropriate; thmap_create should not fail. We really need to pass KM_SLEEP through in this call site even though there are other call sites for which KM_NOSLEEP is appropriate. Adapted from: rmind/thmap#14 PR kern/57666 rmind/thmap#13 XXX pullup-10 XXX pullup-9
rokuyama
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Oct 26, 2023
sys/kern/subr_thmap.c: revision 1.14 sys/kern/subr_thmap.c: revision 1.15 thmap(9): Test alloc failure, not THMAP_GETPTR failure. THMAP_GETPTR may return nonnull even though alloc returned zero. Note that this failure branch is not actually appropriate; thmap_create should not fail. We really need to pass KM_SLEEP through in this call site even though there are other call sites for which KM_NOSLEEP is appropriate. Adapted from: rmind/thmap#14 PR kern/57666 rmind/thmap#13 thmap(9): Preallocate GC list storage for thmap_del. thmap_del can't fail, and it is used in places in npf where sleeping is forbidden, so it can't rely on allocating memory either. Instead of having thmap_del allocate memory on the fly for each object to defer freeing until thmap_gc, arrange to have thmap(9) preallocate the same storage when allocating all the objects in the first place, with a GC header. This is suboptimal for memory usage, especially on insertion- and lookup-heavy but deletion-light workloads, but it's not clear rmind's alternative (https://github.com/rmind/thmap/tree/thmap_del_mem_fail) is ready to use yet, so we'll go with this for correctness. PR kern/57208 rmind/npf#129
rokuyama
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Oct 27, 2023
sys/kern/subr_thmap.c: revision 1.14 sys/kern/subr_thmap.c: revision 1.15 thmap(9): Test alloc failure, not THMAP_GETPTR failure. THMAP_GETPTR may return nonnull even though alloc returned zero. Note that this failure branch is not actually appropriate; thmap_create should not fail. We really need to pass KM_SLEEP through in this call site even though there are other call sites for which KM_NOSLEEP is appropriate. Adapted from: rmind/thmap#14 PR kern/57666 rmind/thmap#13 thmap(9): Preallocate GC list storage for thmap_del. thmap_del can't fail, and it is used in places in npf where sleeping is forbidden, so it can't rely on allocating memory either. Instead of having thmap_del allocate memory on the fly for each object to defer freeing until thmap_gc, arrange to have thmap(9) preallocate the same storage when allocating all the objects in the first place, with a GC header. This is suboptimal for memory usage, especially on insertion- and lookup-heavy but deletion-light workloads, but it's not clear rmind's alternative (https://github.com/rmind/thmap/tree/thmap_del_mem_fail) is ready to use yet, so we'll go with this for correctness. PR kern/57208 rmind/npf#129
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Adapt test so it never returns zero on success.
fix #13