On (09/15/15 09:18), Vitaly Wool wrote:

   > On (09/14/15 15:50), Vitaly Wool wrote:
   > > It makes sense to have control over what compression ratios are
   > > ok to store pages uncompressed and what not.
   >
   > um... I don't want this to be exported. this is very 'zram-internal'.
   >
   > besides, you remove the exsiting default value
   > - static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
   >
   > so now people must provide this module param in order to make zram
   > work the way it used to work for years?
   >

   I do not remove it, I move it :) May I ask to review the patch again
   please?

Oh, yep, missed that.

Please read Dan Streetman's reply. I agree with what he said/suggested.


And can you please switch your email client to 'plain text' mode only?
haven't checked, but I suspect that some of vger lists block !plain_text
emails. ... apart from the fact that it's hard to read such emails in
mutt, etc.

	-ss

   >
   > > Moreover, if we end up using zbud allocator for zram, any attempt to
   > > allocate a whole page will fail, so we may want to avoid this as much
   > > as possible.
   >
   > so how does it help?
   >
   > > So, let's have max_zpage_size configurable as a module parameter.
   > >
   > > Signed-off-by: Vitaly Wool <[2]vitalywool@gmail.com>
   > > ---
   > >  drivers/block/zram/zram_drv.c | 13 +++++++++++++
   > >  drivers/block/zram/zram_drv.h | 16 ----------------
   > >  2 files changed, 13 insertions(+), 16 deletions(-)
   > >
   > > diff --git a/drivers/block/zram/zram_drv.c
   b/drivers/block/zram/zram_drv.c
   > > index 9fa15bb..6d9f1d1 100644
   > > --- a/drivers/block/zram/zram_drv.c
   > > +++ b/drivers/block/zram/zram_drv.c
   > > @@ -42,6 +42,7 @@ static const char *default_compressor = "lzo";
   > >
   > >  /* Module params (documentation at end) */
   > >  static unsigned int num_devices = 1;
   > > +static size_t max_zpage_size = PAGE_SIZE / 4 * 3;
   > >
   > >  static inline void deprecated_attr_warn(const char *name)
   > >  {
   > > @@ -1411,6 +1412,16 @@ static int __init zram_init(void)
   > >               return ret;
   > >       }
   > >
   > > +     /*
   > > +      * max_zpage_size must be less than or equal to:
   > > +      * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
   > > +      * always return failure.
   > > +      */
   > > +     if (max_zpage_size > PAGE_SIZE) {
   > > +             pr_err("Invalid max_zpage_size %ld\n", max_zpage_size);
   >
   > and how do people find out ZS_MAX_ALLOC_SIZE? this error message does
   not
   > help.
   >
   > > +             return -EINVAL;
   > > +     }
   > > +
   > >       zram_major = register_blkdev(0, "zram");
   > >       if (zram_major <= 0) {
   > >               pr_err("Unable to get major number\n");
   > > @@ -1444,6 +1455,8 @@ module_exit(zram_exit);
   > >
   > >  module_param(num_devices, uint, 0);
   > >  MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
   > > +module_param(max_zpage_size, ulong, 0);
   > > +MODULE_PARM_DESC(max_zpage_size, "Threshold for storing compressed
   pages");
   >
   > unclear description.
   >
   >
   > >
   > >  MODULE_LICENSE("Dual BSD/GPL");
   > >  MODULE_AUTHOR("Nitin Gupta <[3]ngupta@vflare.org>");
   > > diff --git a/drivers/block/zram/zram_drv.h
   b/drivers/block/zram/zram_drv.h
   > > index 8e92339..3a29c33 100644
   > > --- a/drivers/block/zram/zram_drv.h
   > > +++ b/drivers/block/zram/zram_drv.h
   > > @@ -20,22 +20,6 @@
   > >
   > >  #include "zcomp.h"
   > >
   > > -/*-- Configurable parameters */
   > > -
   > > -/*
   > > - * Pages that compress to size greater than this are stored
   > > - * uncompressed in memory.
   > > - */
   > > -static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
   > > -
   > > -/*
   > > - * NOTE: max_zpage_size must be less than or equal to:
   > > - *   ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
   > > - * always return failure.
   > > - */
   > > -
   > > -/*-- End of configurable params */
   > > -
   > >  #define SECTOR_SHIFT         9
   > >  #define SECTORS_PER_PAGE_SHIFT       (PAGE_SHIFT - SECTOR_SHIFT)
   > >  #define SECTORS_PER_PAGE     (1 << SECTORS_PER_PAGE_SHIFT)
   > > --
   > > 1.9.1
   > >
   > > --
   > > To unsubscribe, send a message with 'unsubscribe linux-mm' in
   > > the body to [4]majordomo@kvack.org.  For more info on Linux MM,
   > > see: [5]http://www.linux-mm.org/ .
   > > Don't email: <a href=mailto:"[6]dont@kvack.org"> [7]email@kvack.org
   </a>
   > >

References

   Visible links
   1. mailto:sergey.senozhatsky.work@gmail.com
   2. mailto:vitalywool@gmail.com
   3. mailto:ngupta@vflare.org
   4. mailto:majordomo@kvack.org
   5. http://www.linux-mm.org/
   6. mailto:dont@kvack.org
   7. mailto:email@kvack.org

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>