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Message-ID: <5226CC9D.30904@linux.vnet.ibm.com> Date: Wed, 04 Sep 2013 11:31:01 +0530 From: Aruna Balakrishnaiah <aruna@...ux.vnet.ibm.com> To: Seiji Aguchi <seiji.aguchi@....com> CC: "Luck, Tony" <tony.luck@...el.com>, "jkenisto@...ux.vnet.ibm.com" <jkenisto@...ux.vnet.ibm.com>, "keescook@...omium.org" <keescook@...omium.org>, "mahesh@...ux.vnet.ibm.com" <mahesh@...ux.vnet.ibm.com>, "ccross@...roid.com" <ccross@...roid.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linuxppc-dev@...abs.org" <linuxppc-dev@...abs.org>, "cbouatmailru@...il.com" <cbouatmailru@...il.com> Subject: Re: [RFC PATCH v2 04/11] pstore: Add compression support to pstore On Wednesday 04 September 2013 07:14 AM, Seiji Aguchi wrote: > Aruna, > > Sorry for the late response. > >> Seiji, >> >> Could you let us know the efivars buffer size with which the pstore is >> registered when >> the failure occurred. > I looked into the issue today. > > I added some debug message just before pstore_compress(). > As you can see below, the buffer size is a fixed value(1024). > Therefore, the size doesn't seem to be related to the failure directly. > > Also, in the failure case, zlib_deflate() returns Z_OK and stream.avail_out is zero. > So, I thought big_oops_buf_sz is too big in my environment. > And then, I tuned big_oops_buf_sz to (psinfo->bufsize * 100) / 53. Seiji, Thank you for the analysis. The reason behind compression failure is the size of big_oops_buf which is too big for efivars case. I will do some experiments with different kind of texts for buffer size 1024 to check if 100/53 suits for all the cases. > > At the same time, while looking into this issue, I had two concerns about current cording. > > 1) In pstore_decompress(), why not use zlib_inflateInit2() instead of zlib_inflateInit()? > If you use zlib_deflateInit2() for specifying window_bit at compressing time, > zlib_inflateInit2() seems to be appropriate for decompressing. > (Please see a comment about inflateInit2() in include/linux/zlib.h and source code of crypto/deflate.c) Yes this can be changed to zlib_inflateInit2(). > 2) As looking at crypto/deflate.c, stream->workspace is kzalloced at the beginning of > compressing/decompressing time. > So, in pstore case, stream.workspace must be initialized to 0 with memset() in pstore_compress()/decompress(). Hmm.. I don't think this is a issue. If you see fs/logfs/compr.c from which I derived the compression algorithms for pstore as well, they have not initialized stream.workspace. Since the space will be overwritten during the calculation, I dont think it will matter. The above 2 things you have suggested are good to have. But the reason behind compression failure is the big_oops_buf_sz which is too big for efivars. > I did three things above, tuning big_oops_buf_sz, using zlib_inflateInit2() and initializing stream.workspace , in my environment. > As a result, compressions/decmpressions of all entries succeeded with efivars driver. > > <snip> > Panic#2 Part1 > <4>[ 75.665020] [<ffffffff811af59c>] SyS_write+0x4c/0xa0 > <4>[ 75.665020] [<ffffffff8168be82>] system_call_fastpath+0x16/0x1b > <4>[ 75.665020] Code: ef e8 ff f7 ff ff eb d8 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 0f 1f 44 00 00 55 c7 05 cc f3 c9 00 01 00 00 00 48 89 e5 0f ae f8 <c6> 04 25 00 00 00 00 01 5d c3 0f 1f 44 00 00 55 31 c0 c7 05 5e > <1>[ 75.665020] RIP [<ffffffff813d3946>] sysrq_handle_crash+0x16/0x20 > <4>[ 75.665020] RSP <ffff88007852de80> > <4>[ 75.665020] CR2: 0000000000000000 > <4>[ 75.665020] ---[ end trace 97bb4a1f8d3fe7b2 ]--- > <3>[ 75.665020] pstore_dump hsize=13 len=2155 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=13 len=2246 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore: compression failed for Part 2 returned -5 > <3>[ 75.665020] pstore: Capture uncompressed oops/panic report of Part 2 > <3>[ 75.665020] pstore_dump hsize=13 len=2239 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=13 len=2231 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=13 len=2185 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore: compression failed for Part 5 returned -5 > <3>[ 75.665020] pstore: Capture uncompressed oops/panic report of Part 5 > <3>[ 75.665020] pstore_dump hsize=13 len=2234 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=13 len=2208 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=13 len=2218 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=13 len=2222 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore: compression failed for Part 9 returned -5 > <3>[ 75.665020] pstore: Capture uncompressed oops/panic report of Part 9 > <3>[ 75.665020] pstore_dump hsize=14 len=2256 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=14 len=2219 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <3>[ 75.665020] pstore_dump hsize=14 len=2226 big_oops_buf_sz=2275 psinfo->bufsize=1024 > <0>[ 75.665020] Kernel panic - not syncing: Fatal exception > <3>[ 75.665020] drm_kms_helper: panic occurred, switching back to text console > <snip> > > Seiji > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@...ts.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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