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[lib] Move some ZSTD_CCtx_params off the stack
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* Take `params` by const reference in `ZSTD_resetCCtx_internal()`.
* Add `simpleApiParams` to the CCtx and use them in the simple API
  functions, instead of creating those parameters on the stack.

I think this is a good direction to move in, because we shouldn't need
to worry about adding parameters to `ZSTD_CCtx_params`, since it should
always be on the heap (unless they become absoultely gigantic).

Some `ZSTD_CCtx_params` are still on the stack in the CDict functions,
but I've left them for now, because it was a little more complex, and we
don't use those functions in stack-constrained currently.
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@terrelln
terrelln committed May 5, 2021
1 parent 2d10544 commit c2183d7
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Showing 2 changed files with 37 additions and 33 deletions.
69 changes: 36 additions & 33 deletions lib/compress/zstd_compress.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1802,38 +1802,44 @@ static int ZSTD_dictTooBig(size_t const loadedDictSize)
* note : `params` are assumed fully validated at this stage.
*/
static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
ZSTD_CCtx_params params,
ZSTD_CCtx_params const* params,
U64 const pledgedSrcSize,
size_t const loadedDictSize,
ZSTD_compResetPolicy_e const crp,
ZSTD_buffered_policy_e const zbuff)
{
ZSTD_cwksp* const ws = &zc->workspace;
DEBUGLOG(4, "ZSTD_resetCCtx_internal: pledgedSrcSize=%u, wlog=%u, useRowMatchFinder=%d",
(U32)pledgedSrcSize, params.cParams.windowLog, (int)params.useRowMatchFinder);
assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
(U32)pledgedSrcSize, params->cParams.windowLog, (int)params->useRowMatchFinder);
assert(!ZSTD_isError(ZSTD_checkCParams(params->cParams)));

zc->isFirstBlock = 1;

assert(params.useRowMatchFinder != ZSTD_urm_auto);
if (params.ldmParams.enableLdm) {
/* Set applied params early so we can modify them for LDM,
* and point params at the applied params.
*/
zc->appliedParams = *params;
params = &zc->appliedParams;

assert(params->useRowMatchFinder != ZSTD_urm_auto);
if (params->ldmParams.enableLdm) {
/* Adjust long distance matching parameters */
ZSTD_ldm_adjustParameters(&params.ldmParams, &params.cParams);
assert(params.ldmParams.hashLog >= params.ldmParams.bucketSizeLog);
assert(params.ldmParams.hashRateLog < 32);
ZSTD_ldm_adjustParameters(&zc->appliedParams.ldmParams, &params->cParams);
assert(params->ldmParams.hashLog >= params->ldmParams.bucketSizeLog);
assert(params->ldmParams.hashRateLog < 32);
}

{ size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params.cParams.windowLog), pledgedSrcSize));
{ size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params->cParams.windowLog), pledgedSrcSize));
size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, windowSize);
U32 const divider = (params.cParams.minMatch==3) ? 3 : 4;
U32 const divider = (params->cParams.minMatch==3) ? 3 : 4;
size_t const maxNbSeq = blockSize / divider;
size_t const buffOutSize = (zbuff == ZSTDb_buffered && params.outBufferMode == ZSTD_bm_buffered)
size_t const buffOutSize = (zbuff == ZSTDb_buffered && params->outBufferMode == ZSTD_bm_buffered)
? ZSTD_compressBound(blockSize) + 1
: 0;
size_t const buffInSize = (zbuff == ZSTDb_buffered && params.inBufferMode == ZSTD_bm_buffered)
size_t const buffInSize = (zbuff == ZSTDb_buffered && params->inBufferMode == ZSTD_bm_buffered)
? windowSize + blockSize
: 0;
size_t const maxNbLdmSeq = ZSTD_ldm_getMaxNbSeq(params.ldmParams, blockSize);
size_t const maxNbLdmSeq = ZSTD_ldm_getMaxNbSeq(params->ldmParams, blockSize);

int const indexTooClose = ZSTD_indexTooCloseToMax(zc->blockState.matchState.window);
int const dictTooBig = ZSTD_dictTooBig(loadedDictSize);
Expand All @@ -1842,7 +1848,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,

size_t const neededSpace =
ZSTD_estimateCCtxSize_usingCCtxParams_internal(
&params.cParams, &params.ldmParams, zc->staticSize != 0, params.useRowMatchFinder,
&params->cParams, &params->ldmParams, zc->staticSize != 0, params->useRowMatchFinder,
buffInSize, buffOutSize, pledgedSrcSize);
int resizeWorkspace;

Expand Down Expand Up @@ -1885,8 +1891,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
ZSTD_cwksp_clear(ws);

/* init params */
zc->appliedParams = params;
zc->blockState.matchState.cParams = params.cParams;
zc->blockState.matchState.cParams = params->cParams;
zc->pledgedSrcSizePlusOne = pledgedSrcSize+1;
zc->consumedSrcSize = 0;
zc->producedCSize = 0;
Expand Down Expand Up @@ -1917,11 +1922,11 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
zc->outBuff = (char*)ZSTD_cwksp_reserve_buffer(ws, buffOutSize);

/* ldm bucketOffsets table */
if (params.ldmParams.enableLdm) {
if (params->ldmParams.enableLdm) {
/* TODO: avoid memset? */
size_t const numBuckets =
((size_t)1) << (params.ldmParams.hashLog -
params.ldmParams.bucketSizeLog);
((size_t)1) << (params->ldmParams.hashLog -
params->ldmParams.bucketSizeLog);
zc->ldmState.bucketOffsets = ZSTD_cwksp_reserve_buffer(ws, numBuckets);
ZSTD_memset(zc->ldmState.bucketOffsets, 0, numBuckets);
}
Expand All @@ -1937,16 +1942,16 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
FORWARD_IF_ERROR(ZSTD_reset_matchState(
&zc->blockState.matchState,
ws,
&params.cParams,
params.useRowMatchFinder,
&params->cParams,
params->useRowMatchFinder,
crp,
needsIndexReset,
ZSTD_resetTarget_CCtx), "");

/* ldm hash table */
if (params.ldmParams.enableLdm) {
if (params->ldmParams.enableLdm) {
/* TODO: avoid memset? */
size_t const ldmHSize = ((size_t)1) << params.ldmParams.hashLog;
size_t const ldmHSize = ((size_t)1) << params->ldmParams.hashLog;
zc->ldmState.hashTable = (ldmEntry_t*)ZSTD_cwksp_reserve_aligned(ws, ldmHSize * sizeof(ldmEntry_t));
ZSTD_memset(zc->ldmState.hashTable, 0, ldmHSize * sizeof(ldmEntry_t));
zc->ldmSequences = (rawSeq*)ZSTD_cwksp_reserve_aligned(ws, maxNbLdmSeq * sizeof(rawSeq));
Expand Down Expand Up @@ -2031,7 +2036,7 @@ ZSTD_resetCCtx_byAttachingCDict(ZSTD_CCtx* cctx,
cdict->dictContentSize, ZSTD_cpm_attachDict);
params.cParams.windowLog = windowLog;
params.useRowMatchFinder = cdict->useRowMatchFinder; /* cdict overrides */
FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, &params, pledgedSrcSize,
/* loadedDictSize */ 0,
ZSTDcrp_makeClean, zbuff), "");
assert(cctx->appliedParams.cParams.strategy == adjusted_cdict_cParams.strategy);
Expand Down Expand Up @@ -2084,7 +2089,7 @@ static size_t ZSTD_resetCCtx_byCopyingCDict(ZSTD_CCtx* cctx,
params.cParams = *cdict_cParams;
params.cParams.windowLog = windowLog;
params.useRowMatchFinder = cdict->useRowMatchFinder;
FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, &params, pledgedSrcSize,
/* loadedDictSize */ 0,
ZSTDcrp_leaveDirty, zbuff), "");
assert(cctx->appliedParams.cParams.strategy == cdict_cParams->strategy);
Expand Down Expand Up @@ -2190,7 +2195,7 @@ static size_t ZSTD_copyCCtx_internal(ZSTD_CCtx* dstCCtx,
assert(srcCCtx->appliedParams.useRowMatchFinder != ZSTD_urm_auto);
params.useRowMatchFinder = srcCCtx->appliedParams.useRowMatchFinder;
params.fParams = fParams;
ZSTD_resetCCtx_internal(dstCCtx, params, pledgedSrcSize,
ZSTD_resetCCtx_internal(dstCCtx, &params, pledgedSrcSize,
/* loadedDictSize */ 0,
ZSTDcrp_leaveDirty, zbuff);
assert(dstCCtx->appliedParams.cParams.windowLog == srcCCtx->appliedParams.cParams.windowLog);
Expand Down Expand Up @@ -4422,7 +4427,7 @@ static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
return ZSTD_resetCCtx_usingCDict(cctx, cdict, params, pledgedSrcSize, zbuff);
}

FORWARD_IF_ERROR( ZSTD_resetCCtx_internal(cctx, *params, pledgedSrcSize,
FORWARD_IF_ERROR( ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
dictContentSize,
ZSTDcrp_makeClean, zbuff) , "");
{ size_t const dictID = cdict ?
Expand Down Expand Up @@ -4591,15 +4596,14 @@ size_t ZSTD_compress_advanced (ZSTD_CCtx* cctx,
const void* dict,size_t dictSize,
ZSTD_parameters params)
{
ZSTD_CCtx_params cctxParams;
DEBUGLOG(4, "ZSTD_compress_advanced");
FORWARD_IF_ERROR(ZSTD_checkCParams(params.cParams), "");
ZSTD_CCtxParams_init_internal(&cctxParams, &params, ZSTD_NO_CLEVEL);
ZSTD_CCtxParams_init_internal(&cctx->simpleApiParams, &params, ZSTD_NO_CLEVEL);
return ZSTD_compress_advanced_internal(cctx,
dst, dstCapacity,
src, srcSize,
dict, dictSize,
&cctxParams);
&cctx->simpleApiParams);
}

/* Internal */
Expand All @@ -4623,14 +4627,13 @@ size_t ZSTD_compress_usingDict(ZSTD_CCtx* cctx,
const void* dict, size_t dictSize,
int compressionLevel)
{
ZSTD_CCtx_params cctxParams;
{
ZSTD_parameters const params = ZSTD_getParams_internal(compressionLevel, srcSize, dict ? dictSize : 0, ZSTD_cpm_noAttachDict);
assert(params.fParams.contentSizeFlag == 1);
ZSTD_CCtxParams_init_internal(&cctxParams, &params, (compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT: compressionLevel);
ZSTD_CCtxParams_init_internal(&cctx->simpleApiParams, &params, (compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT: compressionLevel);
}
DEBUGLOG(4, "ZSTD_compress_usingDict (srcSize=%u)", (unsigned)srcSize);
return ZSTD_compress_advanced_internal(cctx, dst, dstCapacity, src, srcSize, dict, dictSize, &cctxParams);
return ZSTD_compress_advanced_internal(cctx, dst, dstCapacity, src, srcSize, dict, dictSize, &cctx->simpleApiParams);
}

size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx,
Expand Down
1 change: 1 addition & 0 deletions lib/compress/zstd_compress_internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -340,6 +340,7 @@ struct ZSTD_CCtx_s {
int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
ZSTD_CCtx_params requestedParams;
ZSTD_CCtx_params appliedParams;
ZSTD_CCtx_params simpleApiParams; /* Param storage used by the simple API - not sticky. Must only be used in top-level simple API functions for storage. */
U32 dictID;
size_t dictContentSize;

Expand Down

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