upstream/mercurial-mirror Files · contrib/fuzz/xdiff.cc

memory-usage: fix `hg log --follow --rev R F` space complexity...

memory-usage: fix `hg log --follow --rev R F` space complexity When running `hg log --follow --rev REVS FILES`, the log code will walk the history of all FILES starting from the file revisions that exists in each REVS. Before doing so, it looks if the files actually exists in the target revisions. To do so, it opens the manifest of each revision in REVS to look up if we find the associated items in FILES. Before this changeset this was done in a way that created a changectx for each target revision, keeping them in memory while we look into each file. If the set of REVS is large, this means keeping the manifest for each entry in REVS in memory. That can be large… if REV is in the form `::X`, this can quickly become huge and saturate the memory. We have seen usage allocating 2GB per second until memory runs out. So this changeset invert the two loop so that only one revision is kept in memory during the operation. This solve the memory explosion issue.

Augie Fackler - - Load All Authors

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r44255:7857bd9b default


                r50517:dcb2581e

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      /*

       * xdiff.cc - fuzzer harness for thirdparty/xdiff

       *

       * Copyright 2018, Google Inc.

       *

       * This software may be used and distributed according to the terms of

       * the GNU General Public License, incorporated herein by reference.

       */

      #include "thirdparty/xdiff/xdiff.h"

      #include <inttypes.h>

      #include <stdlib.h>

      #include "FuzzedDataProvider.h"

      extern "C" {

      int LLVMFuzzerInitialize(int *argc, char ***argv)

      {

      	return 0;

      }

      int hunk_consumer(long a1, long a2, long b1, long b2, void *priv)

      {

      	// TODO: probably also test returning -1 from this when things break?

      	return 0;

      }

      int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)

      {

      	// Don't allow fuzzer inputs larger than 100k, since we'll just bog

      	// down and not accomplish much.

      	if (Size > 100000) {

      		return 0;

      	}

      	FuzzedDataProvider provider(Data, Size);

      	std::string left = provider.ConsumeRandomLengthString(Size);

      	std::string right = provider.ConsumeRemainingBytesAsString();

      	mmfile_t a, b;

      	a.ptr = (char *)left.c_str();

      	a.size = left.size();

      	b.ptr = (char *)right.c_str();

      	b.size = right.size();

      	xpparam_t xpp = {

      	    XDF_INDENT_HEURISTIC, /* flags */

      	};

      	xdemitconf_t xecfg = {

      	    XDL_EMIT_BDIFFHUNK, /* flags */

      	    hunk_consumer,      /* hunk_consume_func */

      	};

      	xdemitcb_t ecb = {

      	    NULL, /* priv */

      	};

      	xdl_diff(&a, &b, &xpp, &xecfg, &ecb);

      	return 0; // Non-zero return values are reserved for future use.

      }

      } // extern "C"

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				/*
				* xdiff.cc - fuzzer harness for thirdparty/xdiff
				*
				* Copyright 2018, Google Inc.
				*
				* This software may be used and distributed according to the terms of
				* the GNU General Public License, incorporated herein by reference.
				*/
				#include "thirdparty/xdiff/xdiff.h"
				#include <inttypes.h>
				#include <stdlib.h>

				#include "FuzzedDataProvider.h"

				extern "C" {

				int LLVMFuzzerInitialize(int argc, char **argv)
				{
				return 0;
				}

				int hunk_consumer(long a1, long a2, long b1, long b2, void *priv)
				{
				// TODO: probably also test returning -1 from this when things break?
				return 0;
				}

				int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
				{
				// Don't allow fuzzer inputs larger than 100k, since we'll just bog
				// down and not accomplish much.
				if (Size > 100000) {
				return 0;
				}
				FuzzedDataProvider provider(Data, Size);
				std::string left = provider.ConsumeRandomLengthString(Size);
				std::string right = provider.ConsumeRemainingBytesAsString();
				mmfile_t a, b;

				a.ptr = (char *)left.c_str();
				a.size = left.size();
				b.ptr = (char *)right.c_str();
				b.size = right.size();
				xpparam_t xpp = {
				XDF_INDENT_HEURISTIC, /* flags */
				};
				xdemitconf_t xecfg = {
				XDL_EMIT_BDIFFHUNK, /* flags */
				hunk_consumer, /* hunk_consume_func */
				};
				xdemitcb_t ecb = {
				NULL, /* priv */
				};
				xdl_diff(&a, &b, &xpp, &xecfg, &ecb);
				return 0; // Non-zero return values are reserved for future use.
				}

				} // extern "C"