Messages in this thread | | | Subject | Re: [PATCH] mm/fadvise: discard partial pages iff endbyte is also eof | From | "夷则(Caspar)" <> | Date | Thu, 04 Jan 2018 15:44:20 +0800 |
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On 2018/1/4 14:13, 夷则(Caspar) wrote: > > This patch is trying to help to solve a real issue. Sometimes we need to > evict the whole file from page cache because we are sure it will not be > used in the near future. We try to use posix_fadvise() to finish our > work but we often see a "small tail" at the end of some files could not > be evicted, after digging a little bit, we find those file sizes are not > page-aligned and the "tail" turns out to be partial pages. > > We fail to find a standard from posix_fadvise() manual page to subscribe > the function behaviors if the `offset' and `len' params are not
Oops, I find a 'standard' documented in latest man-pages.git[1], blame my centos7, it runs with an old man-pages.rpm :-(
Thanks, Caspar
[1] https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?h=ceb1c326b9f3e863dfd9bf33bc7118bb1fa29bfc
> page-aligned, then we go to kernel tree and see this: > > /* > * First and last FULL page! Partial pages are deliberately > * preserved on the expectation that it is better to preserve > * needed memory than to discard unneeded memory. > */
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