From 50a58b9bda2fdc58af658f6797368c3a7d05b55d Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Wed, 28 Jun 2023 13:25:51 +0200 Subject: [PATCH] Add elfutils-0.189-elf_getdata_rawchunk.patch Resolves: #2218041 Performance issue in elf_getdata_rawchunk --- elfutils-0.189-elf_getdata_rawchunk.patch | 224 ++++++++++++++++++++++ elfutils.spec | 5 + 2 files changed, 229 insertions(+) create mode 100644 elfutils-0.189-elf_getdata_rawchunk.patch diff --git a/elfutils-0.189-elf_getdata_rawchunk.patch b/elfutils-0.189-elf_getdata_rawchunk.patch new file mode 100644 index 0000000..7ce6695 --- /dev/null +++ b/elfutils-0.189-elf_getdata_rawchunk.patch @@ -0,0 +1,224 @@ +From 3aca5b5f1f1617db2220022d9061dcaf129e54c4 Mon Sep 17 00:00:00 2001 +From: Mark Wielaard +Date: Wed, 21 Jun 2023 18:05:12 +0200 +Subject: [PATCH] libelf: Replace list of elf_getdata_rawchunk results with a + tree + +elf_getdata_rawchunks did a linear search to see if a chunk was +already fetched. Replace this list with a binary search tree to make +lookup faster when a lot of Elf_Data_Chunk were created. + + * libelf/libelfP.h (Elf_Data_Chunk): Remove next field. + (struct Elf): Change the rawchunks type from Elf_Data_Chunk * + to void *. + * elf_getdata_rawchunk.c (chunk_compare): New static function. + (elf_getdata_rawchunk): Use tsearch instead of a manual linked + list. + * elf_end.c (free_chunk): New static function. + (elf_end): Call tdestroy instead of walking linked list. + +Signed-off-by: Mark Wielaard +--- + libelf/elf_end.c | 22 +++++++++------- + libelf/elf_getdata_rawchunk.c | 47 +++++++++++++++++++++++++---------- + libelf/libelfP.h | 13 ++++------ + 3 files changed, 52 insertions(+), 30 deletions(-) + +diff --git a/libelf/elf_end.c b/libelf/elf_end.c +index 5c451f36..3e5d4c86 100644 +--- a/libelf/elf_end.c ++++ b/libelf/elf_end.c +@@ -1,5 +1,6 @@ + /* Free resources associated with Elf descriptor. + Copyright (C) 1998,1999,2000,2001,2002,2004,2005,2007,2015,2016 Red Hat, Inc. ++ Copyright (C) 2023 Mark J. Wielaard + This file is part of elfutils. + Written by Ulrich Drepper , 1998. + +@@ -32,12 +33,22 @@ + #endif + + #include ++#include + #include + #include + + #include "libelfP.h" + + ++static void ++free_chunk (void *n) ++{ ++ Elf_Data_Chunk *rawchunk = (Elf_Data_Chunk *)n; ++ if (rawchunk->dummy_scn.flags & ELF_F_MALLOCED) ++ free (rawchunk->data.d.d_buf); ++ free (rawchunk); ++} ++ + int + elf_end (Elf *elf) + { +@@ -112,20 +123,13 @@ elf_end (Elf *elf) + + case ELF_K_ELF: + { +- Elf_Data_Chunk *rawchunks ++ void *rawchunks + = (elf->class == ELFCLASS32 + || (offsetof (struct Elf, state.elf32.rawchunks) + == offsetof (struct Elf, state.elf64.rawchunks)) + ? elf->state.elf32.rawchunks + : elf->state.elf64.rawchunks); +- while (rawchunks != NULL) +- { +- Elf_Data_Chunk *next = rawchunks->next; +- if (rawchunks->dummy_scn.flags & ELF_F_MALLOCED) +- free (rawchunks->data.d.d_buf); +- free (rawchunks); +- rawchunks = next; +- } ++ tdestroy (rawchunks, free_chunk); + + Elf_ScnList *list = (elf->class == ELFCLASS32 + || (offsetof (struct Elf, state.elf32.scns) +diff --git a/libelf/elf_getdata_rawchunk.c b/libelf/elf_getdata_rawchunk.c +index 5a35ccdc..cfd40396 100644 +--- a/libelf/elf_getdata_rawchunk.c ++++ b/libelf/elf_getdata_rawchunk.c +@@ -1,6 +1,6 @@ + /* Return converted data from raw chunk of ELF file. + Copyright (C) 2007, 2014, 2015 Red Hat, Inc. +- Copyright (C) 2022 Mark J. Wielaard ++ Copyright (C) 2022, 2023 Mark J. Wielaard + This file is part of elfutils. + + This file is free software; you can redistribute it and/or modify +@@ -33,12 +33,28 @@ + + #include + #include ++#include + #include + #include + + #include "libelfP.h" + #include "common.h" + ++static int ++chunk_compare (const void *a, const void *b) ++{ ++ Elf_Data_Chunk *da = (Elf_Data_Chunk *)a; ++ Elf_Data_Chunk *db = (Elf_Data_Chunk *)b; ++ ++ if (da->offset != db->offset) ++ return da->offset - db->offset; ++ ++ if (da->data.d.d_size != db->data.d.d_size) ++ return da->data.d.d_size - db->data.d.d_size; ++ ++ return da->data.d.d_type - db->data.d.d_type; ++} ++ + Elf_Data * + elf_getdata_rawchunk (Elf *elf, int64_t offset, size_t size, Elf_Type type) + { +@@ -75,19 +91,25 @@ elf_getdata_rawchunk (Elf *elf, int64_t offset, size_t size, Elf_Type type) + rwlock_rdlock (elf->lock); + + /* Maybe we already got this chunk? */ +- Elf_Data_Chunk *rawchunks = elf->state.elf.rawchunks; +- while (rawchunks != NULL) ++ Elf_Data_Chunk key; ++ key.offset = offset; ++ key.data.d.d_size = size; ++ key.data.d.d_type = type; ++ Elf_Data_Chunk **found = tsearch (&key, &elf->state.elf.rawchunks, ++ &chunk_compare); ++ if (found == NULL) ++ goto nomem; ++ ++ /* Existing entry. */ ++ if (*found != &key && *found != NULL) + { +- if ((rawchunks->offset == offset || size == 0) +- && rawchunks->data.d.d_size == size +- && rawchunks->data.d.d_type == type) +- { +- result = &rawchunks->data.d; +- goto out; +- } +- rawchunks = rawchunks->next; ++ result = &(*found)->data.d; ++ goto out; + } + ++ /* New entry. */ ++ *found = NULL; ++ + size_t align = __libelf_type_align (elf->class, type); + if (elf->map_address != NULL) + { +@@ -189,8 +211,7 @@ elf_getdata_rawchunk (Elf *elf, int64_t offset, size_t size, Elf_Type type) + rwlock_unlock (elf->lock); + rwlock_wrlock (elf->lock); + +- chunk->next = elf->state.elf.rawchunks; +- elf->state.elf.rawchunks = chunk; ++ *found = chunk; + result = &chunk->data.d; + + out: +diff --git a/libelf/libelfP.h b/libelf/libelfP.h +index 6624f38a..d3c241e5 100644 +--- a/libelf/libelfP.h ++++ b/libelf/libelfP.h +@@ -1,5 +1,6 @@ + /* Internal interfaces for libelf. + Copyright (C) 1998-2010, 2015, 2016 Red Hat, Inc. ++ Copyright (C) 2023 Mark J. Wielaard + This file is part of elfutils. + Contributed by Ulrich Drepper , 1998. + +@@ -262,11 +263,7 @@ typedef struct Elf_ScnList + typedef struct Elf_Data_Chunk + { + Elf_Data_Scn data; +- union +- { +- Elf_Scn dummy_scn; +- struct Elf_Data_Chunk *next; +- }; ++ Elf_Scn dummy_scn; + int64_t offset; /* The original raw offset in the Elf image. */ + } Elf_Data_Chunk; + +@@ -324,7 +321,7 @@ struct Elf + Elf_ScnList *scns_last; /* Last element in the section list. + If NULL the data has not yet been + read from the file. */ +- Elf_Data_Chunk *rawchunks; /* List of elf_getdata_rawchunk results. */ ++ void *rawchunks; /* Tree of elf_getdata_rawchunk results. */ + unsigned int scnincr; /* Number of sections allocate the last + time. */ + int ehdr_flags; /* Flags (dirty) for ELF header. */ +@@ -343,7 +340,7 @@ struct Elf + Elf_ScnList *scns_last; /* Last element in the section list. + If NULL the data has not yet been + read from the file. */ +- Elf_Data_Chunk *rawchunks; /* List of elf_getdata_rawchunk results. */ ++ void *rawchunks; /* Tree of elf_getdata_rawchunk results. */ + unsigned int scnincr; /* Number of sections allocate the last + time. */ + int ehdr_flags; /* Flags (dirty) for ELF header. */ +@@ -368,7 +365,7 @@ struct Elf + Elf_ScnList *scns_last; /* Last element in the section list. + If NULL the data has not yet been + read from the file. */ +- Elf_Data_Chunk *rawchunks; /* List of elf_getdata_rawchunk results. */ ++ void *rawchunks; /* Tree of elf_getdata_rawchunk results. */ + unsigned int scnincr; /* Number of sections allocate the last + time. */ + int ehdr_flags; /* Flags (dirty) for ELF header. */ +-- +2.40.1 + diff --git a/elfutils.spec b/elfutils.spec index b97e1fd..4c63418 100644 --- a/elfutils.spec +++ b/elfutils.spec @@ -67,6 +67,8 @@ BuildRequires: gettext-devel # elfcompress: Don't compress if section already compressed unless forced Patch1: elfutils-0.189-elfcompress.patch +# libelf: Replace list of elf_getdata_rawchunk results with a tree +Patch2: elfutils-0.189-elf_getdata_rawchunk.patch %description Elfutils is a collection of utilities, including stack (to show @@ -457,6 +459,9 @@ exit 0 %systemd_postun_with_restart debuginfod.service %changelog +* Wed Jun 28 2023 Mark Wielaard +- Add elfutils-0.189-elf_getdata_rawchunk.patch + * Mon Apr 24 2023 Mark Wielaard - 0.189-2 - Add elfutils-0.189-elfcompress.patch