On Wed, Sep 18, 2019 at 6:57 PM Tom Seewald <tseewald@xxxxxxxxx> wrote: > > Hi Chris, > > Does zswap actually keep the data compressed when the DRAM-based swap is full, and it writes to the spill-over non-volatile swap device? > > I'm not an expert on this at all, however my understanding was that zswap must decompress the data before it writes to the backing swap. But perhaps I am misunderstanding the purpose of zswap_writeback_entry()[1] and/or what it does. > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/zswap.c#n828 I don't know. But based on the tests I mention upthread, I'm not sure how uncompressed pages are being swapped to disk. But then those times don't account for even a 2:1 compression ratio, which is the best that zbud/lz4 can achieve. -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
