From: Andreas Dilger Subject: [PATCH] ext* free space fragmentation reporting Date: Mon, 21 Jul 2008 15:13:34 -0600 Message-ID: <20080721211334.GP3370@webber.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7BIT Cc: "Theodore Ts'o" To: linux-ext4@vger.kernel.org Return-path: Received: from sca-es-mail-2.Sun.COM ([192.18.43.133]:49451 "EHLO sca-es-mail-2.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750784AbYGUVNw (ORCPT ); Mon, 21 Jul 2008 17:13:52 -0400 Received: from fe-sfbay-09.sun.com ([192.18.43.129]) by sca-es-mail-2.sun.com (8.13.7+Sun/8.12.9) with ESMTP id m6LLDqlK023145 for ; Mon, 21 Jul 2008 14:13:52 -0700 (PDT) Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007)) id <0K4D00G01JXPVD00@fe-sfbay-09.sun.com> (original mail from adilger@sun.com) for linux-ext4@vger.kernel.org; Mon, 21 Jul 2008 14:13:52 -0700 (PDT) Content-disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: We wrote a tool for Lustre which reports the free space fragmentation in ext* filesystems. There was a request on linuxfs to get a copy of this patch, and I thought it would be potentially useful for others as well. The patch is against 1.40.11, but I don't think it would need to change much (if any) for 1.40.1 because it only uses public libext2fs interfaces. - builds a histogram of different sizes of aligned contiguous free space 4k..128MB, which is what mballoc will be checking for - reports the min/max/average size of contiguous chunks of free space - reports the percent of free space in "chunksize" chunks (default 1MB) Signed-off-by: Andreas Dilger Signed-off-by: Kalpak Shah Index: e2fsprogs-1.40.7/misc/e2freefrag.8.in =================================================================== --- /dev/null +++ e2fsprogs-1.40.7/misc/e2freefrag.8.in @@ -0,0 +1,100 @@ +.\" -*- nroff -*- +.TH E2FREEFRAG 8 +.SH NAME +e2freefrag \- report free space fragmentation +.SH SYNOPSIS +.B e2freefrag +[ +.B \-c chunk_kb +] +[ +.B \-h +] +.B filesys + +.SH DESCRIPTION +.B e2freefrag +is used to report free space fragmentation on ext2/3/4 file systems. +.I filesys +can be a device name (e.g. +.IR /dev/hdc1 ", " /dev/sdb2 ). +The +.B e2freefrag +program will scan the block bitmap information to check how many free blocks +are present as contiguous free space. The percentage of contiguous free blocks +of size and of alignment +.IR chunk_kb +is reported. It also displays the minimum/maximum/average free chunk size in +the filesystem. It also displays an histogram of all free chunks. This +information can be used to gauge the level of free space fragmentation in the +filesystem. +.SH OPTIONS +.TP +.BI \-c " chunk_kb" +Desired size of chunk. It is specified in units of kilobytes (KB). If no +.I chunk_kb +is specified on the command line, then the default value is 1024KB. +.TP +.BI \-h +Print the usage of the program. +.SH EXAMPLE +# e2freefrag -c 1024 /dev/sda5 +.br +Device: /dev/sda5 +.br +Blocksize: 4096 bytes +.br + +Total blocks: 5120710 +.br +Free blocks: 831744 (16.2%) +.br + +Total chunks: 20003 +.br +Free chunks: 2174 (10.9%) +.br + +Min free chunk: 4 KB +.br +Max free chunk: 24576 KB +.br +Avg. free chunk: 340 KB +.br + +HISTOGRAM OF FREE CHUNK SIZES: +.br + Range Free chunks +.br + 4K... 8K- : 2824 +.br + 8K... 16K- : 1760 +.br + 16K... 32K- : 1857 +.br + 32K... 64K- : 1003 +.br + 64K... 128K- : 616 +.br + 128K... 256K- : 479 +.br + 256K... 512K- : 302 +.br + 512K... 1024K- : 238 +.br + 1M... 2M- : 213 +.br + 2M... 4M- : 173 +.br + 4M... 8M- : 287 +.br + 8M... 16M- : 4 +.br + 16M... 32M- : 1 +.SH AUTHOR +This version of e2freefrag was written by Rupesh Thakare, and modified by +Andreas Dilger and Kalpak Shah . +.SH SEE ALSO +.IR debugfs (8), +.IR dumpe2fs (8), +.IR e2fsck (8) Index: e2fsprogs-1.40.7/misc/e2freefrag.c =================================================================== --- /dev/null +++ e2fsprogs-1.40.7/misc/e2freefrag.c @@ -0,0 +1,261 @@ +#include +#ifdef HAVE_UNISTD_H +#include +#endif +#ifdef HAVE_STDLIB_H +#include +#endif +#ifdef HAVE_GETOPT_H +#include +#else +extern char *optarg; +extern int optind; +#endif + +#include "ext2fs/ext2_fs.h" +#include "ext2fs/ext2fs.h" +#include "e2freefrag.h" + +void usage(const char *prog) +{ + fprintf(stderr, "usage: %s [-c chunksize in kb] [-h] " + "device_name\n", prog); + exit(1); +} + +static int ul_log2(unsigned long arg) +{ + int l = 0; + + arg >>= 1; + while (arg) { + l++; + arg >>= 1; + } + return l; +} + +void init_chunk_info(ext2_filsys fs, struct chunk_info *info) +{ + int i; + + info->chunkbits = ul_log2(info->chunkbytes); + info->blocksize_bits = ul_log2((unsigned long)fs->blocksize); + info->blks_in_chunk = info->chunkbytes >> info->blocksize_bits; + + info->min = ~0UL; + info->max = info->avg = 0; + info->real_free_chunks = 0; + + for (i = 0; i < MAX_HIST; i++) + info->histogram.fc_buckets[i] = 0; +} + +void scan_block_bitmap(ext2_filsys fs, struct chunk_info *info) +{ + unsigned long blocks_count = fs->super->s_blocks_count; + unsigned long chunks = (blocks_count + info->blks_in_chunk) >> + (info->chunkbits - info->blocksize_bits); + unsigned long chunk_num; + unsigned long last_chunk_size = 0; + unsigned long index; + blk_t blk; + int ret, not_free = 0, free_chunk = 0; + + for (chunk_num = 0; chunk_num < chunks; chunk_num++) { + blk_t chunk_start_blk = chunk_num << (info->chunkbits - + info->blocksize_bits); + unsigned long num_blks; + + /* Last chunk may be smaller */ + if (chunk_start_blk + info->blks_in_chunk > blocks_count) + num_blks = blocks_count - chunk_start_blk; + else + num_blks = info->blks_in_chunk; + + free_chunk = 0; + for (blk = 0; blk < num_blks; blk++) { + if (ext2fs_fast_test_block_bitmap(fs->block_map, + chunk_start_blk + blk)) { + not_free = 1; + } else { + last_chunk_size++; + free_chunk++; + not_free = 0; + } + + if (not_free) { + if (last_chunk_size == 0) + continue; + + index = ul_log2(last_chunk_size) + 1; + info->histogram.fc_buckets[index]++; + + if (last_chunk_size > info->max) + info->max = last_chunk_size; + if (last_chunk_size < info->min) + info->min = last_chunk_size; + info->avg += last_chunk_size; + + info->real_free_chunks++; + last_chunk_size = 0; + } + } + + if (free_chunk == info->blks_in_chunk) + info->free_chunks++; + } +} + +errcode_t get_chunk_info(ext2_filsys fs, struct chunk_info *info) +{ + unsigned long total_chunks; + char *unitp = "KMGTPEZY"; + int units = 10; + unsigned long start = 0, end, cum; + int i, retval = 0; + + scan_block_bitmap(fs, info); + + printf("\nTotal blocks: %lu\nFree blocks: %lu (%0.1f%%)\n", + fs->super->s_blocks_count, fs->super->s_free_blocks_count, + (double)fs->super->s_free_blocks_count * 100 / + fs->super->s_blocks_count); + + total_chunks = (fs->super->s_blocks_count + info->blks_in_chunk) >> + (info->chunkbits - info->blocksize_bits); + printf("\nTotal chunks: %lu\nFree chunks: %lu (%0.1f%%)\n", + total_chunks, info->free_chunks, + (double)info->free_chunks * 100 / total_chunks); + + /* Display chunk information in KB */ + if (info->real_free_chunks) { + info->min = (info->min * fs->blocksize) >> 10; + info->max = (info->max * fs->blocksize) >> 10; + info->avg = (info->avg / info->real_free_chunks * + fs->blocksize) >> 10; + } else { + info->min = 0; + } + + printf("\nMin free chunk: %lu KB \nMax free chunk: %lu KB\n" + "Avg. free chunk: %lu KB\n", info->min, info->max, info->avg); + + printf("\nHISTOGRAM OF FREE CHUNK SIZES:\n"); + printf("%15s\t\t%10s\n", "Range", "Free chunks"); + for (i = 0; i < MAX_HIST; i++) { + end = 1 << (i + info->blocksize_bits - units); + if (info->histogram.fc_buckets[i] != 0) + printf("%5lu%c...%5lu%c- : %10lu\n", start, *unitp, + end, *unitp, info->histogram.fc_buckets[i]); + start = end; + if (start == 1<<10) { + start = 1; + units += 10; + unitp++; + } + } + + return retval; +} + +void close_device(char *device_name, ext2_filsys fs) +{ + int retval = ext2fs_close(fs); + + if (retval) + com_err(device_name, retval, "while closing the filesystem.\n"); +} + +void collect_info(ext2_filsys fs, struct chunk_info *chunk_info) +{ + unsigned int retval = 0, i, free_blks; + + printf("Device: %s\n", fs->device_name); + printf("Blocksize: %u bytes\n", fs->blocksize); + + retval = ext2fs_read_block_bitmap(fs); + if (retval) { + com_err(fs->device_name, retval, "while reading block bitmap"); + close_device(fs->device_name, fs); + exit(1); + } + + init_chunk_info(fs, chunk_info); + + retval = get_chunk_info(fs, chunk_info); + if (retval) { + com_err(fs->device_name, retval, "while collecting chunk info"); + close_device(fs->device_name, fs); + exit(1); + } +} + +void open_device(char *device_name, ext2_filsys *fs) +{ + int retval; + int flag = EXT2_FLAG_FORCE; + + retval = ext2fs_open(device_name, flag, 0, 0, unix_io_manager, fs); + if (retval) { + com_err(device_name, retval, "while opening filesystem"); + exit(1); + } +} + +int main(int argc, char *argv[]) +{ + struct chunk_info chunk_info = { .chunkbytes = DEFAULT_CHUNKSIZE }; + errcode_t retval = 0; + ext2_filsys fs = NULL; + char *device_name; + char *progname; + char c, *end; + + progname = argv[0]; + + while ((c = getopt(argc, argv, "c:h")) != EOF) { + switch (c) { + case 'c': + chunk_info.chunkbytes = strtoull(optarg, &end, 0); + if (*end != '\0') { + fprintf(stderr, "%s: bad chunk size '%s'\n", + progname, optarg); + usage(progname); + } + if (chunk_info.chunkbytes & + (chunk_info.chunkbytes - 1)) { + fprintf(stderr, "%s: chunk size must be a " + "power of 2."); + usage(progname); + } + chunk_info.chunkbytes *= 1024; + break; + default: + fprintf(stderr, "%s: bad option '%c'\n", + progname, c); + case 'h': + usage(progname); + break; + } + } + + if (optind == argc) { + fprintf(stderr, "%s: missing device name.\n", progname); + usage(progname); + } + + device_name = argv[optind]; + + open_device(device_name, &fs); + + if (chunk_info.chunkbytes < fs->blocksize) { + fprintf(stderr, "%s: chunksize must be greater than or equal " + "to filesystem blocksize.\n", progname); + exit(1); + } + collect_info(fs, &chunk_info); + close_device(device_name, fs); + + return retval; +} Index: e2fsprogs-1.40.7/misc/e2freefrag.h =================================================================== --- /dev/null +++ e2fsprogs-1.40.7/misc/e2freefrag.h @@ -0,0 +1,20 @@ +#include + +#define DEFAULT_CHUNKSIZE (1024*1024) + +#define MAX_HIST 32 +struct free_chunk_histogram { + unsigned long fc_buckets[MAX_HIST]; +}; + +struct chunk_info { + unsigned long chunkbytes; /* chunk size in bytes */ + int chunkbits; /* chunk size in bits */ + unsigned long free_chunks; /* total no of free chunks of given size */ + unsigned long real_free_chunks; /* free chunks of any size */ + int blocksize_bits; /* fs blocksize in bits */ + int blks_in_chunk; /* number of blocks in a chunk */ + unsigned long min, max, avg; /* chunk size stats */ + struct free_chunk_histogram histogram; /* histogram of chunks of all sizes */ +}; + Index: e2fsprogs-1.40.7/e2fsprogs.spec.in =================================================================== --- e2fsprogs-1.40.7.orig/e2fsprogs.spec.in +++ e2fsprogs-1.40.7/e2fsprogs.spec.in @@ -138,6 +138,7 @@ exit 0 %{_root_sbindir}/tune2fs %{_sbindir}/filefrag %{_sbindir}/mklost+found +%{_sbindir}/e2freefrag %{_root_libdir}/libblkid.so.* %{_root_libdir}/libcom_err.so.* @@ -177,6 +178,7 @@ exit 0 %{_mandir}/man8/resize2fs.8* %{_mandir}/man8/tune2fs.8* %{_mandir}/man8/filefrag.8* +%{_mandir}/man8/e2freefrag.8* %files devel %defattr(-,root,root) Index: e2fsprogs-1.40.7/misc/Makefile.in =================================================================== --- e2fsprogs-1.40.7.orig/misc/Makefile.in +++ e2fsprogs-1.40.7/misc/Makefile.in @@ -19,10 +19,10 @@ INSTALL = @INSTALL@ SPROGS= mke2fs badblocks tune2fs dumpe2fs blkid logsave \ $(E2IMAGE_PROG) @FSCK_PROG@ -USPROGS= mklost+found filefrag $(UUIDD_PROG) +USPROGS= mklost+found filefrag e2freefrag $(UUIDD_PROG) SMANPAGES= tune2fs.8 mklost+found.8 mke2fs.8 dumpe2fs.8 badblocks.8 \ e2label.8 findfs.8 blkid.8 $(E2IMAGE_MAN) \ - logsave.8 filefrag.8 $(UUIDD_MAN) @FSCK_MAN@ + logsave.8 filefrag.8 e2freefrag.8 $(UUIDD_MAN) @FSCK_MAN@ FMANPAGES= mke2fs.conf.5 UPROGS= chattr lsattr uuidgen @@ -43,6 +43,7 @@ E2IMAGE_OBJS= e2image.o FSCK_OBJS= fsck.o base_device.o ismounted.o BLKID_OBJS= blkid.o FILEFRAG_OBJS= filefrag.o +E2FREEFRAG_OBJS= e2freefrag.o XTRA_CFLAGS= -I$(srcdir)/../e2fsck -I. @@ -51,7 +52,8 @@ SRCS= $(srcdir)/tune2fs.c $(srcdir)/mklo $(srcdir)/badblocks.c $(srcdir)/fsck.c $(srcdir)/util.c \ $(srcdir)/uuidgen.c $(srcdir)/blkid.c $(srcdir)/logsave.c \ $(srcdir)/filefrag.c $(srcdir)/base_device.c \ - $(srcdir)/ismounted.c $(srcdir)/../e2fsck/profile.c + $(srcdir)/ismounted.c $(srcdir)/../e2fsck/profile.c \ + $(srcdir)/e2freefrag.c LIBS= $(LIBEXT2FS) $(LIBCOM_ERR) DEPLIBS= $(LIBEXT2FS) $(LIBCOM_ERR) @@ -169,6 +171,10 @@ logsave: logsave.o @echo " LD $@" @$(CC) $(ALL_LDFLAGS) -o logsave logsave.o +e2freefrag: $(E2FREEFRAG_OBJS) + @echo "LD $@" + @$(CC) $(ALL_LDFLAGS) -o e2freefrag $(E2FREEFRAG_OBJS) $(LIBS) + filefrag: $(FILEFRAG_OBJS) @echo " LD $@" @$(CC) $(ALL_LDFLAGS) -o filefrag $(FILEFRAG_OBJS) @@ -245,6 +251,10 @@ blkid.1: $(DEP_SUBSTITUTE) $(srcdir)/blk @echo " SUBST $@" @$(SUBSTITUTE_UPTIME) $(srcdir)/blkid.1.in blkid.1 +e2freefrag.8: $(DEP_SUBSTITUTE) $(srcdir)/e2freefrag.8.in + @echo " SUBST $@" + @$(SUBSTITUTE_UPTIME) $(srcdir)/e2freefrag.8.in e2freefrag.8 + filefrag.8: $(DEP_SUBSTITUTE) $(srcdir)/filefrag.8.in @echo " SUBST $@" @$(SUBSTITUTE_UPTIME) $(srcdir)/filefrag.8.in filefrag.8 @@ -370,7 +380,7 @@ uninstall: clean: $(RM) -f $(SPROGS) $(USPROGS) $(UPROGS) $(UMANPAGES) $(SMANPAGES) \ $(FMANPAGES) \ - base_device base_device.out mke2fs.static filefrag \ + base_device base_device.out mke2fs.static filefrag e2freefrag \ e2initrd_helper partinfo prof_err.[ch] default_profile.c \ uuidd e2image tst_ismounted \#* *.s *.o *.a *~ core @@ -446,6 +456,9 @@ uuidgen.o: $(srcdir)/uuidgen.c $(top_src blkid.o: $(srcdir)/blkid.c $(top_srcdir)/lib/blkid/blkid.h \ $(top_builddir)/lib/blkid/blkid_types.h logsave.o: $(srcdir)/logsave.c +e2freefrag.o: $(srcdir)/e2freefrag.c e2freefrag.h \ + $(top_srcdir)/lib/ext2fs/ext2_fs.h $(top_srcdir)/lib/ext2fs/ext2fs.h \ + $(top_srcdir)/lib/ext2fs/bitops.h filefrag.o: $(srcdir)/filefrag.c base_device.o: $(srcdir)/base_device.c $(srcdir)/fsck.h ismounted.o: $(srcdir)/ismounted.c $(top_srcdir)/lib/et/com_err.h Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc.