[lkml]   [2006]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Subjectdifferences between MADV_FREE and MADV_DONTNEED
Now that MADV_REMOVE is in, should we discuss MADV_FREE?

MADV_FREE in Solaris is destructive and only works on anonymous memory,
while MADV_DONTNEED seems to never be destructive (which I assume it
means it's a noop on anonymous memory).

Our MADV_DONTNEED is destructive on anonymous memory, while it's
non-destructive on file mappings.

Perhaps we could move the destructive anonymous part of MADV_DONTNEED to

Or we could as well go relaxed and define MADV_FREE and MADV_DONTNEED
the same way (that still leaves the question if we risk to break apps
ported from solaris where MADV_DONTNEED is apparently always not

I only read the docs, I don't know in practice what MADV_DONTNEED does
on solaris (does it return -EINVAL if run on anonymous memory or not?).

BTW, I don't know how other specifications define MADV_FREE, but besides
MADV_REMOVE I've also got the request to provide MADV_FREE in linux,
this is why I'm asking. (right now I'm telling them to use #ifdef
__linux__ #define MADV_FREE MADV_DONTNEED but that's quite an hack since
it could break if we make MADV_DONTNEED non-destructive in the future)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-01-16 14:09    [W:0.102 / U:7.180 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site