On 06/22/2011 05:51 PM, Andrea Righi wrote:
There were some reported problems in the past about trashing page cache when a backup software (i.e., rsync) touches a huge amount of pages (see for example [1]). This problem has been almost fixed by the Minchan Kim's patch [2] and a proper use of fadvise() in the backup software. For example this patch set [3] has been proposed for inclusion in rsync. However, there can be still other similar trashing problems: when the backup software reads all the source files, some of them may be part of the actual working set of the system. When a posix_fadvise(POSIX_FADV_DONTNEED) is performed _all_ pages are evicted from pagecache, both the working set and the use-once pages touched only by the backup software. With the following solution when posix_fadvise(POSIX_FADV_DONTNEED) is called for an active page instead of removing it from the page cache it is added to the tail of the inactive list. Otherwise, if it's already in the inactive list the page is removed from the page cache.
Signed-off-by: Andrea Righi<andrea@xxxxxxxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx> -- All rights reversed -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>