Re: Bug in huge simplehash
On 2021-08-13 14:40:08 +0300, Yura Sokolov wrote: > Ranier Vilela писал 2021-08-13 14:12: > > Em sex., 13 de ago. de 2021 às 07:15, Andres Freund > > escreveu: > > > Personally I find it more obvious to understand the intended > > > behaviour > > > with ~0 (i.e. all bits set) than with a width truncation. > > > > https://godbolt.org/z/57WcjKqMj > > The generated code is identical. > > I believe, you mean https://godbolt.org/z/qWzE1ePTE I don't think the choice of instructions matters. This is called around creation and resizing - the other costs are several orders of magnitude more expensive than determining the mask.
Re: Bug in huge simplehash
Ranier Vilela писал 2021-08-13 14:12: Em sex., 13 de ago. de 2021 às 07:15, Andres Freund escreveu: Hi, On 2021-08-13 12:44:17 +0300, Yura Sokolov wrote: Andres Freund писал 2021-08-13 12:21: Any chance you'd write a test for simplehash with such huge amount of values? It'd require a small bit of trickery to be practical. On systems with MAP_NORESERVE it should be feasible. Which way C structures should be tested in postgres? dynahash/simplhash - do they have any tests currently? I'll do if hint is given. We don't have a great way right now :(. I think the best is to have a SQL callable function that uses some API. See e.g. test_atomic_ops() et al in src/test/regress/regress.c > static inline void > -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) > +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) > { > uint64 size; > > @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 > newsize) > > /* now set size */ > tb->size = size; > - > - if (tb->size == SH_MAX_SIZE) > - tb->sizemask = 0; > - else > - tb->sizemask = tb->size - 1; > + tb->sizemask = (uint32)(size - 1); ISTM using ~0 would be nicer here? I don't think so. To be rigid it should be `~(uint32)0`. But I believe it doesn't differ from `tb->sizemask = (uint32)(size - 1)` that is landed with patch, therefore why `if` is needed? Personally I find it more obvious to understand the intended behaviour with ~0 (i.e. all bits set) than with a width truncation. https://godbolt.org/z/57WcjKqMj The generated code is identical. I believe, you mean https://godbolt.org/z/qWzE1ePTE regards, Ranier Vilela
Re: Bug in huge simplehash
Em sex., 13 de ago. de 2021 às 07:15, Andres Freund escreveu: > Hi, > > On 2021-08-13 12:44:17 +0300, Yura Sokolov wrote: > > Andres Freund писал 2021-08-13 12:21: > > > Any chance you'd write a test for simplehash with such huge amount of > > > values? It'd require a small bit of trickery to be practical. On > systems > > > with MAP_NORESERVE it should be feasible. > > > > Which way C structures should be tested in postgres? > > dynahash/simplhash - do they have any tests currently? > > I'll do if hint is given. > > We don't have a great way right now :(. I think the best is to have a > SQL callable function that uses some API. See e.g. test_atomic_ops() et > al in src/test/regress/regress.c > > > > > > static inline void > > > > -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) > > > > +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) > > > > { > > > > uint64 size; > > > > > > > > @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 > > > > newsize) > > > > > > > > /* now set size */ > > > > tb->size = size; > > > > - > > > > - if (tb->size == SH_MAX_SIZE) > > > > - tb->sizemask = 0; > > > > - else > > > > - tb->sizemask = tb->size - 1; > > > > + tb->sizemask = (uint32)(size - 1); > > > > > > ISTM using ~0 would be nicer here? > > > > I don't think so. > > To be rigid it should be `~(uint32)0`. > > But I believe it doesn't differ from `tb->sizemask = (uint32)(size - 1)` > > that is landed with patch, therefore why `if` is needed? > > Personally I find it more obvious to understand the intended behaviour > with ~0 (i.e. all bits set) than with a width truncation. > https://godbolt.org/z/57WcjKqMj The generated code is identical. regards, Ranier Vilela
Re: Bug in huge simplehash
Hi, On 2021-08-13 12:44:17 +0300, Yura Sokolov wrote: > Andres Freund писал 2021-08-13 12:21: > > Any chance you'd write a test for simplehash with such huge amount of > > values? It'd require a small bit of trickery to be practical. On systems > > with MAP_NORESERVE it should be feasible. > > Which way C structures should be tested in postgres? > dynahash/simplhash - do they have any tests currently? > I'll do if hint is given. We don't have a great way right now :(. I think the best is to have a SQL callable function that uses some API. See e.g. test_atomic_ops() et al in src/test/regress/regress.c > > > static inline void > > > -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) > > > +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) > > > { > > > uint64 size; > > > > > > @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 > > > newsize) > > > > > > /* now set size */ > > > tb->size = size; > > > - > > > - if (tb->size == SH_MAX_SIZE) > > > - tb->sizemask = 0; > > > - else > > > - tb->sizemask = tb->size - 1; > > > + tb->sizemask = (uint32)(size - 1); > > > > ISTM using ~0 would be nicer here? > > I don't think so. > To be rigid it should be `~(uint32)0`. > But I believe it doesn't differ from `tb->sizemask = (uint32)(size - 1)` > that is landed with patch, therefore why `if` is needed? Personally I find it more obvious to understand the intended behaviour with ~0 (i.e. all bits set) than with a width truncation. Greetings, Andres Freund
Re: Bug in huge simplehash
Andres Freund писал 2021-08-13 12:21: Hi, On 2021-08-10 11:52:59 +0300, Yura Sokolov wrote: - sizemask is set only in SH_COMPUTE_PARAMETERS . And it is set in this way: /* now set size */ tb->size = size; if (tb->size == SH_MAX_SIZE) tb->sizemask = 0; else tb->sizemask = tb->size - 1; that means, when we are resizing to SH_MAX_SIZE, sizemask becomes zero. I think that was intended to be ~0. I believe so. Ahh... ok, patch is updated to fix this as well. Any chance you'd write a test for simplehash with such huge amount of values? It'd require a small bit of trickery to be practical. On systems with MAP_NORESERVE it should be feasible. Which way C structures should be tested in postgres? dynahash/simplhash - do they have any tests currently? I'll do if hint is given. static inline void -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) { uint64 size; @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) /* now set size */ tb->size = size; - - if (tb->size == SH_MAX_SIZE) - tb->sizemask = 0; - else - tb->sizemask = tb->size - 1; + tb->sizemask = (uint32)(size - 1); ISTM using ~0 would be nicer here? I don't think so. To be rigid it should be `~(uint32)0`. But I believe it doesn't differ from `tb->sizemask = (uint32)(size - 1)` that is landed with patch, therefore why `if` is needed? Greetings, Andres Freund
Re: Bug in huge simplehash
Hi, On 2021-08-10 11:52:59 +0300, Yura Sokolov wrote: > - sizemask is set only in SH_COMPUTE_PARAMETERS . And it is set in this way: > > /* now set size */ > tb->size = size; > > if (tb->size == SH_MAX_SIZE) > tb->sizemask = 0; > else > tb->sizemask = tb->size - 1; > > that means, when we are resizing to SH_MAX_SIZE, sizemask becomes zero. I think that was intended to be ~0. > Ahh... ok, patch is updated to fix this as well. Any chance you'd write a test for simplehash with such huge amount of values? It'd require a small bit of trickery to be practical. On systems with MAP_NORESERVE it should be feasible. > static inline void > -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) > +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) > { > uint64 size; > > @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) > > /* now set size */ > tb->size = size; > - > - if (tb->size == SH_MAX_SIZE) > - tb->sizemask = 0; > - else > - tb->sizemask = tb->size - 1; > + tb->sizemask = (uint32)(size - 1); ISTM using ~0 would be nicer here? Greetings, Andres Freund
Re: Bug in huge simplehash
On Wed, 11 Aug 2021 at 00:10, Yura Sokolov wrote: > Attached v2. Eyeballing this it looks fine, but I was a little nervous backpatching without testing it properly, so I ended up provisioning a machine with 256GB and doing a round of testing. I just created the most simple table I could: create table a (a bigserial, b int); and inserted 2^31 rows. insert into a (b) values(1); insert into a (b) select b from a; -- repeated until I got 2^31 rows. set work_mem = '256GB'; set max_parallel_workers_per_gather = 0; I could recreate the issue described with the following query: explain (analyze , timing off) select a from a group by a; After watching perf top for a while it switched to: 98.90% postgres[.] tuplehash_grow 0.36% [kernel][k] change_p4d_range 0.24% postgres[.] LookupTupleHashEntry 0.09% postgres[.] tts_minimal_store_tuple 0.07% [kernel][k] vm_normal_page 0.02% [kernel][k] __softirqentry_text_start 0.02% postgres[.] heap_fill_tuple 0.02% postgres[.] AllocSetAlloc After patching I got: explain (analyze , timing off) select a from a group by a; QUERY PLAN - HashAggregate (cost=35149810.71..53983243.28 rows=1883343257 width=8) (actual rows=2147483648 loops=1) Group Key: a Batches: 1 Memory Usage: 201334801kB -> Seq Scan on a (cost=0.00..30441452.57 rows=1883343257 width=8) (actual rows=2147483648 loops=1) Planning Time: 0.105 ms Execution Time: 2173480.905 ms (6 rows) Time: 2173482.166 ms (36:13.482) And, since I only had 256GB of memory on this machine and couldn't really do 2^32 groups, I dropped SH_FILLFACTOR to 0.4 and SH_MAX_FILLFACTOR to 0.48 and tried again to ensure I got the hash table full message: postgres=# explain (analyze on , timing off) select a from a group by a; ERROR: hash table size exceeded Time: 1148554.672 ms (19:08.555) After doing that, I felt a bit better about batch-patching it, so I did. Thanks for the patch. David
Re: Bug in huge simplehash
Ranier Vilela писал 2021-08-10 14:21: Em ter., 10 de ago. de 2021 às 05:53, Yura Sokolov escreveu: I went to check SH_GROW and It is `SH_GROW(SH_TYPE *tb, uint32 newsize)` :-((( Therefore when `tb->size == SH_MAX_SIZE/2` and we call `SH_GROW(tb, tb->size * 2)`, then SH_GROW(tb, 0) is called due to truncation. And SH_COMPUTE_PARAMETERS is also accepts `uint32 newsize`. Ahh... ok, patch is updated to fix this as well. It seems that we need to fix the function prototype too. /* void _grow(_hash *tb) */ -SH_SCOPE void SH_GROW(SH_TYPE * tb, uint32 newsize); +SH_SCOPE void SH_GROW(SH_TYPE * tb, uint64 newsize); Ahh... Thank you, Ranier. Attached v2. regards, - Yura SokolovFrom 82f449896d62be8440934d955d4e368f057005a6 Mon Sep 17 00:00:00 2001 From: Yura Sokolov Date: Tue, 10 Aug 2021 11:51:16 +0300 Subject: [PATCH] Fix new size and sizemask computaton in simplehash.h Fix couple of 32/64bit related errors in simplehash.h: - size of SH_GROW and SH_COMPUTE_PARAMETERS arguments - computation of tb->sizemask. --- src/include/lib/simplehash.h | 14 +- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/src/include/lib/simplehash.h b/src/include/lib/simplehash.h index da51781e98e..adda5598338 100644 --- a/src/include/lib/simplehash.h +++ b/src/include/lib/simplehash.h @@ -198,8 +198,8 @@ SH_SCOPE void SH_DESTROY(SH_TYPE * tb); /* void _reset(_hash *tb) */ SH_SCOPE void SH_RESET(SH_TYPE * tb); -/* void _grow(_hash *tb) */ -SH_SCOPE void SH_GROW(SH_TYPE * tb, uint32 newsize); +/* void _grow(_hash *tb, uint64 newsize) */ +SH_SCOPE void SH_GROW(SH_TYPE * tb, uint64 newsize); /* *_insert(_hash *tb, key, bool *found) */ SH_SCOPE SH_ELEMENT_TYPE *SH_INSERT(SH_TYPE * tb, SH_KEY_TYPE key, bool *found); @@ -302,7 +302,7 @@ SH_SCOPE void SH_STAT(SH_TYPE * tb); * the hashtable. */ static inline void -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) { uint64 size; @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) /* now set size */ tb->size = size; - - if (tb->size == SH_MAX_SIZE) - tb->sizemask = 0; - else - tb->sizemask = tb->size - 1; + tb->sizemask = (uint32)(size - 1); /* * Compute the next threshold at which we need to grow the hash table @@ -476,7 +472,7 @@ SH_RESET(SH_TYPE * tb) * performance-wise, when known at some point. */ SH_SCOPE void -SH_GROW(SH_TYPE * tb, uint32 newsize) +SH_GROW(SH_TYPE * tb, uint64 newsize) { uint64 oldsize = tb->size; SH_ELEMENT_TYPE *olddata = tb->data; -- 2.32.0
Re: Bug in huge simplehash
Em ter., 10 de ago. de 2021 às 05:53, Yura Sokolov escreveu: > Good day, hackers. > > Our client caught process stuck in tuplehash_grow. There was a query > like > `select ts, count(*) from really_huge_partitioned_table group by ts`, > and > planner decided to use hash aggregation. > > Backtrace shows that oldsize were 2147483648 at the moment. While > newsize > were optimized, looks like it were SH_MAX_SIZE. > > #0 0x00603d0c in tuplehash_grow (tb=0x7f18c3c284c8, > newsize=) at ../../../src/include/lib/simplehash.h:457 > hash = 2147483654 > startelem = 1 > curelem = 1 > oldentry = 0x7f00c299e0d8 > oldsize = 2147483648 > olddata = 0x7f00c299e048 > newdata = 0x32e0448 > i = 6 > copyelem = 6 > > EXPLAIN shows that there are 2604186278 rows in all partitions, but > planner > thinks there will be only 200 unique rows after group by. Looks like we > was > mistaken. > > Finalize GroupAggregate (cost=154211885.42..154211936.09 rows=200 > width=16) > Group Key: really_huge_partitioned_table.ts > -> Gather Merge (cost=154211885.42..154211932.09 rows=400 > width=16) >Workers Planned: 2 >-> Sort (cost=154210885.39..154210885.89 rows=200 width=16) > Sort Key: really_huge_partitioned_table.ts > -> Partial HashAggregate > (cost=154210875.75..154210877.75 rows=200 width=16) >Group Key: really_huge_partitioned_table.ts >-> Append (cost=0.43..141189944.36 > rows=2604186278 width=8) > -> Parallel Index Only Scan using > really_huge_partitioned_table_001_idx2 on > really_huge_partitioned_table_001 (cost=0.43..108117.92 rows=2236977 > width=8) > -> Parallel Index Only Scan using > really_huge_partitioned_table_002_idx2 on > really_huge_partitioned_table_002 (cost=0.43..114928.19 rows=2377989 > width=8) > and more than 400 partitions more > > After some investigation I found bug that is present in simplehash from > its > beginning: > > - sizemask is set only in SH_COMPUTE_PARAMETERS . And it is set in this > way: > > /* now set size */ > tb->size = size; > > if (tb->size == SH_MAX_SIZE) > tb->sizemask = 0; > else > tb->sizemask = tb->size - 1; > >that means, when we are resizing to SH_MAX_SIZE, sizemask becomes > zero. > > - then sizemask is used to SH_INITIAL_BUCKET and SH_NEXT to compute > initial and >next position: > >SH_INITIAL_BUCKET(SH_TYPE * tb, uint32 hash) > return hash & tb->sizemask; >SH_NEXT(SH_TYPE * tb, uint32 curelem, uint32 startelem) > curelem = (curelem + 1) & tb->sizemask; > > - and then SH_GROW stuck in element placing loop: > >startelem = SH_INITIAL_BUCKET(tb, hash); >curelem = startelem; >while (true) > curelem = SH_NEXT(tb, curelem, startelem); > > There is Assert(curelem != startelem) in SH_NEXT, but since no one test > it > with 2 billion elements, it were not triggered. And Assert is not > compiled > in production code. > > Attached patch fixes it with removing condition and type casting: > > /* now set size */ > tb->size = size; > tb->sizemask = (uint32)(size - 1); > > > OOPS > > While writting this letter, I looke at newdata in the frame of > tuplehash_grow: > > newdata = 0x32e0448 > > It is bellow 4GB border. Allocator does not allocate many-gigabytes > chunks > (and we certainly need 96GB in this case) in sub 4GB address space. > Because > mmap doesn't do this. > > I went to check SH_GROW and It is `SH_GROW(SH_TYPE *tb, uint32 > newsize)` > :-((( > Therefore when `tb->size == SH_MAX_SIZE/2` and we call `SH_GROW(tb, > tb->size * 2)`, > then SH_GROW(tb, 0) is called due to truncation. > And SH_COMPUTE_PARAMETERS is also accepts `uint32 newsize`. > > Ahh... ok, patch is updated to fix this as well. > It seems that we need to fix the function prototype too. /* void _grow(_hash *tb) */ -SH_SCOPE void SH_GROW(SH_TYPE * tb, uint32 newsize); +SH_SCOPE void SH_GROW(SH_TYPE * tb, uint64 newsize); regards, Ranier Vilela
Re: Bug in huge simplehash
On Tue, 10 Aug 2021 at 20:53, Yura Sokolov wrote: > EXPLAIN shows that there are 2604186278 rows in all partitions, but > planner > thinks there will be only 200 unique rows after group by. Looks like we > was > mistaken. This looks unrelated. Looks like the planner used DEFAULT_NUM_DISTINCT. > /* now set size */ > tb->size = size; > > if (tb->size == SH_MAX_SIZE) > tb->sizemask = 0; > else > tb->sizemask = tb->size - 1; Ouch. That's not great. > /* now set size */ > tb->size = size; > tb->sizemask = (uint32)(size - 1); That fix seems fine. > I went to check SH_GROW and It is `SH_GROW(SH_TYPE *tb, uint32 > newsize)` > :-((( > Therefore when `tb->size == SH_MAX_SIZE/2` and we call `SH_GROW(tb, > tb->size * 2)`, > then SH_GROW(tb, 0) is called due to truncation. > And SH_COMPUTE_PARAMETERS is also accepts `uint32 newsize`. Yeah. Agreed. I don't see anything wrong with your fix for that. I'm surprised nobody has hit this before. I guess having that many groups is not common. Annoyingly this just missed the window for being fixed in the minor releases going out soon. We'll need to wait a few days before patching. David
Bug in huge simplehash
Good day, hackers. Our client caught process stuck in tuplehash_grow. There was a query like `select ts, count(*) from really_huge_partitioned_table group by ts`, and planner decided to use hash aggregation. Backtrace shows that oldsize were 2147483648 at the moment. While newsize were optimized, looks like it were SH_MAX_SIZE. #0 0x00603d0c in tuplehash_grow (tb=0x7f18c3c284c8, newsize=) at ../../../src/include/lib/simplehash.h:457 hash = 2147483654 startelem = 1 curelem = 1 oldentry = 0x7f00c299e0d8 oldsize = 2147483648 olddata = 0x7f00c299e048 newdata = 0x32e0448 i = 6 copyelem = 6 EXPLAIN shows that there are 2604186278 rows in all partitions, but planner thinks there will be only 200 unique rows after group by. Looks like we was mistaken. Finalize GroupAggregate (cost=154211885.42..154211936.09 rows=200 width=16) Group Key: really_huge_partitioned_table.ts -> Gather Merge (cost=154211885.42..154211932.09 rows=400 width=16) Workers Planned: 2 -> Sort (cost=154210885.39..154210885.89 rows=200 width=16) Sort Key: really_huge_partitioned_table.ts -> Partial HashAggregate (cost=154210875.75..154210877.75 rows=200 width=16) Group Key: really_huge_partitioned_table.ts -> Append (cost=0.43..141189944.36 rows=2604186278 width=8) -> Parallel Index Only Scan using really_huge_partitioned_table_001_idx2 on really_huge_partitioned_table_001 (cost=0.43..108117.92 rows=2236977 width=8) -> Parallel Index Only Scan using really_huge_partitioned_table_002_idx2 on really_huge_partitioned_table_002 (cost=0.43..114928.19 rows=2377989 width=8) and more than 400 partitions more After some investigation I found bug that is present in simplehash from its beginning: - sizemask is set only in SH_COMPUTE_PARAMETERS . And it is set in this way: /* now set size */ tb->size = size; if (tb->size == SH_MAX_SIZE) tb->sizemask = 0; else tb->sizemask = tb->size - 1; that means, when we are resizing to SH_MAX_SIZE, sizemask becomes zero. - then sizemask is used to SH_INITIAL_BUCKET and SH_NEXT to compute initial and next position: SH_INITIAL_BUCKET(SH_TYPE * tb, uint32 hash) return hash & tb->sizemask; SH_NEXT(SH_TYPE * tb, uint32 curelem, uint32 startelem) curelem = (curelem + 1) & tb->sizemask; - and then SH_GROW stuck in element placing loop: startelem = SH_INITIAL_BUCKET(tb, hash); curelem = startelem; while (true) curelem = SH_NEXT(tb, curelem, startelem); There is Assert(curelem != startelem) in SH_NEXT, but since no one test it with 2 billion elements, it were not triggered. And Assert is not compiled in production code. Attached patch fixes it with removing condition and type casting: /* now set size */ tb->size = size; tb->sizemask = (uint32)(size - 1); OOPS While writting this letter, I looke at newdata in the frame of tuplehash_grow: newdata = 0x32e0448 It is bellow 4GB border. Allocator does not allocate many-gigabytes chunks (and we certainly need 96GB in this case) in sub 4GB address space. Because mmap doesn't do this. I went to check SH_GROW and It is `SH_GROW(SH_TYPE *tb, uint32 newsize)` :-((( Therefore when `tb->size == SH_MAX_SIZE/2` and we call `SH_GROW(tb, tb->size * 2)`, then SH_GROW(tb, 0) is called due to truncation. And SH_COMPUTE_PARAMETERS is also accepts `uint32 newsize`. Ahh... ok, patch is updated to fix this as well. regards. - Yura Sokolov y.soko...@postgrespro.ru funny.fal...@gmail.comFrom a8283d3a17c630a65e1b42f8617e07873a30fbc7 Mon Sep 17 00:00:00 2001 From: Yura Sokolov Date: Tue, 10 Aug 2021 11:51:16 +0300 Subject: [PATCH] Fix new size and sizemask computaton in simplehash.h Fix couple of 32/64bit related errors in simplehash.h: - size of SH_GROW and SH_COMPUTE_PARAMETERS arguments - computation of tb->sizemask. --- src/include/lib/simplehash.h | 10 +++--- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/src/include/lib/simplehash.h b/src/include/lib/simplehash.h index da51781e98e..2287601cfa1 100644 --- a/src/include/lib/simplehash.h +++ b/src/include/lib/simplehash.h @@ -302,7 +302,7 @@ SH_SCOPE void SH_STAT(SH_TYPE * tb); * the hashtable. */ static inline void -SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) +SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint64 newsize) { uint64 size; @@ -322,11 +322,7 @@ SH_COMPUTE_PARAMETERS(SH_TYPE * tb, uint32 newsize) /* now set size */ tb->size = size; - - if (tb->size == SH_MAX_SIZE) - tb->sizemask = 0; - else - tb->sizemask = tb->size - 1; + tb->sizemask = (uint32)(size - 1); /* * Compute the next threshold at which we need to grow th