Hi Simon, 20.12.2012, 10:21, "Simon Jeons" <simon.jeons@xxxxxxxxx>: > On Sun, 2012-12-16 at 02:15 +0000, Eric Wong wrote: > >> xtu4 <xiaobing.tu@xxxxxxxxx> wrote: >>> resend it, due to format error >>> >>> Subject: [PATCH] when system in low memory scenario, imaging there is a mp3 >>> play, ora video play, we need to read mp3 or video file >>> from memory to page cache,but when system lack of memory, >>> page cache of mp3 or video file will be reclaimed.once read >>> in memory, then reclaimed, it will cause audio or video >>> glitch,and it will increase the io operation at the same >>> time. >> To me, this basically describes how POSIX_FADV_NOREUSE should work. > > Hi Eric, > > But why fadvise POSIX_FADV_NOREUSE almost do nothing? Why not set some > flag or other things for these use once data? Because, it's not clear how should it work in some cases. Do we expect one access? Should we track a page as accessed after any access (even if only one byte was read)? What should we do with already-cached pages? etc. IMHO, it will be better to introduce something like POSIX_FADV_DONTCACHE. Corresponding pages can be added (ratated) to the tail of the inactive LRU after copying data in read() internals, or after minor/major pagefault. > >> I would like to have this ability via fadvise (and not CONFIG_). >> >> Also, I think your patch has too many #ifdefs to be accepted. >> >> -- >> To unsubscribe, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@xxxxxxxxx. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>