From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp09.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 8EB692C0140 for ; Tue, 16 Jul 2013 02:55:20 +1000 (EST) Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 16 Jul 2013 13:50:54 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id D68732CE8052 for ; Tue, 16 Jul 2013 02:55:17 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r6FGe4b78978776 for ; Tue, 16 Jul 2013 02:40:04 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r6FGtGSR010937 for ; Tue, 16 Jul 2013 02:55:17 +1000 Subject: [PATCH 00/11] Add compression support to pstore To: linuxppc-dev@ozlabs.org, paulus@samba.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org From: Aruna Balakrishnaiah Date: Mon, 15 Jul 2013 22:25:04 +0530 Message-ID: <20130715164844.1520.27771.stgit@aruna-ThinkPad-T420> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: jkenisto@linux.vnet.ibm.com, tony.luck@intel.com, mahesh@linux.vnet.ibm.com, cbouatmailru@gmail.com, anton@samba.org, ccross@android.com, keescook@chromium.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The patchset adds compression support to pstore. As the non-volatile storage space is limited, adding compression support results in capturing more data within limited space. Size of dmesg file in a powerpc/pseries box with nvram's oops partition (to store oops-log) size 4k: Without compression: dmesg-nvram-1: ~ 4k (3980) WIth compression: dmesg-nvram-1: ~8.8k (8844) Writing to persistent store ---------------------------- Compression will reduce the size of oops/panic report to atmost 45% of its original size. (Based on experiments done while providing compression support to nvram by Jim keniston). Hence buffer of size ( (100/45 approx 2.22) * is allocated). The compression parameters selected based on some experiments: compression_level = 6, window_bits = 12, memory_level = 4 which achieved a significant compression of 12 % of uncompressed buffer size tried upto 36k. Data is compressed from the bigger buffer to registered buffer which is returned to backends. Pstore will indicate that with a flag 'compressed' which is passed to backends. Using this flag, backends will add a flag in their header to indicate the data is compressed or not while writing to persistent store. Reading from persistent store ----------------------------- When backends read data from persistent store it will use the flag added by it while writing to persistent store to determine if the data is compressed or not. Using the information, it will set the flag in pstore's read call back. Pstore will decompress the data based on the flag and writes decompressed data to the file. Test results: Have tested the patches on powerpc/pseries. On Intel have only tested with erst backend. Efi-pstore and RAM persistent buffer requires testing. --- Aruna Balakrishnaiah (11): powerpc/pseries: Remove (de)compression in nvram with pstore enabled pstore: Add new argument 'compressed' in pstore write callback pstore/Kconfig: Select ZLIB_DEFLATE and ZLIB_INFLATE when PSTORE is selected pstore: Add compression support to pstore pstore: Introduce new argument 'compressed' in the read callback pstore: Provide decompression support to pstore pstore: Add file extension to pstore file if compressed powerpc/pseries: Read and write to the 'compressed' flag of pstore erst: Read and write to the 'compressed' flag of pstore efi-pstore: Read and write to the 'compressed' flag of pstore pstore/ram: Read and write to the 'compressed' flag of pstore arch/powerpc/platforms/pseries/nvram.c | 131 ++++---------------- drivers/acpi/apei/erst.c | 21 ++- drivers/firmware/efi/efi-pstore.c | 27 +++- fs/pstore/Kconfig | 2 fs/pstore/inode.c | 9 + fs/pstore/internal.h | 5 - fs/pstore/platform.c | 214 ++++++++++++++++++++++++++++++-- fs/pstore/ram.c | 41 +++++- include/linux/pstore.h | 6 - 9 files changed, 307 insertions(+), 149 deletions(-) --