On 01/14/2014 12:10 PM, Sergey Senozhatsky wrote: > On (01/14/14 11:38), Jerome Marchand wrote: >> On 01/14/2014 10:37 AM, Sergey Senozhatsky wrote: >>> 1) Introduce ZRAM_ATTR_RO macro to generate zram atomic64_t stats >>> `show' functions and reduce code duplication. >>> >>> 2) Account and report back to user numbers of failed READ and WRITE >>> operations. >>> >>> 3) Remove `good' and `bad' compressed sub-requests stats. RW request may >>> cause a number of RW sub-requests. zram used to account `good' compressed >>> sub-queries (with compressed size less than 50% of original size), `bad' >>> compressed sub-queries (with compressed size greater that 75% of original >>> size), leaving sub-requests with compression size between 50% and 75% of >>> original size not accounted and not reported. >> >> That's weird: good/bad_compress are accounted, but it seems to me that >> they are to never used in any way. If so, there is indeed no reason to >> keep them. >> >> >>> Account each sub-request >>> compression size so we can calculate real device compression ratio. >> >> Your patch doesn't change the way pages_stored and compr[essed]_size >> are accounted. What does your patch change that allow us to calculate >> the "real" compression ratio? >> >>> >>> 4) reported zram stats: >>> - num_writes -- number of writes >>> - num_reads -- number of reads >>> - pages_stored -- number of pages currently stored >>> - compressed_size -- compressed size of pages stored >> >> Wouldn't it be more practical to report the original and compressed >> data sizes using the same units as it is currently done? >> > > hm, do we really need pages_stored stats? what kind of unseful information it > shows to end user?.. perhaps, it's better to replace it with accounted passed > bvec->bv_len (as uncompressed_size). >
That's really going to complicates things. We would need to keep track of which sectors of a particular page has been written to. It's much easier to keep current page granularity and consider any partial I/O as an whole page I/O. > -ss > >> Jerome >> >>> - pages_zero -- number of zero filled pages >>> - failed_read -- number of failed reads >>> - failed_writes -- can happen when memory is too low >>> - invalid_io -- non-page-aligned I/O requests >>> - notify_free -- number of swap slot free notifications >>> - memory_used -- zs pool zs_get_total_size_bytes() >>> >>> Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
