Commit 7de8fe2f authored Sep 11, 2013 by Aruna Balakrishnaiah Committed by Tony Luck Sep 16, 2013

pstore: Adjust buffer size for compression for smaller registered buffers

When backends (ex: efivars) have smaller registered buffers, the
big_oops_buf is too big for them as number of repeated occurences
in the text captured will be less. What happens is that pstore takes
too big a bite from the dmesg log and then finds it cannot compress it
enough to meet the backend block size. Patch takes care of adjusting
the buffer size based on the registered buffer size. cmpr values have
been arrived after doing experiments with plain text for buffers of
size 1k - 4k (Smaller the buffer size repeated occurence will be less)
and with sample crash log for buffers ranging from 4k - 10k.

Reported-by: Seiji Aguchi <seiji.aguchi@hds.com>
Tested-by: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

parent e831cbfc

fs/pstore/platform.c

+22 −1

Original line number	Diff line number	Diff line
		@@ -195,8 +195,29 @@ static int pstore_decompress(void in, void out, size_t inlen, size_t outlen)
		static void allocate_buf_for_compression(void)
		{
		size_t size;
		size_t cmpr;

		big_oops_buf_sz = (psinfo->bufsize * 100) / 45;
		switch (psinfo->bufsize) {
		/* buffer range for efivars */
		case 1000 ... 2000:
		cmpr = 56;
		break;
		case 2001 ... 3000:
		cmpr = 54;
		break;
		case 3001 ... 3999:
		cmpr = 52;
		break;
		/* buffer range for nvram, erst */
		case 4000 ... 10000:
		cmpr = 45;
		break;
		default:
		cmpr = 60;
		break;
		}

		big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
		big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
		if (big_oops_buf) {
		size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),