On Wed, Apr 27, 2011 at 14:33, Matthew Wilcox wrote: > On Wed, Apr 27, 2011 at 08:13:47PM +0200, Andrea Righi wrote: >> @@ -127,6 +128,12 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) >> Â Â Â Â Â Â Â Â Â Â Â invalidate_mapping_pages(mapping, start_index, >> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â end_index); >> Â Â Â Â Â Â Â break; >> + Â Â case POSIX_FADV_DONTNEED_FS: >> + Â Â Â Â Â Â if (capable(CAP_SYS_ADMIN)) >> + Â Â Â Â Â Â Â Â Â Â drop_pagecache_sb(file->f_dentry->d_sb, NULL); >> + Â Â Â Â Â Â else >> + Â Â Â Â Â Â Â Â Â Â ret = -EPERM; >> + Â Â Â Â Â Â break; >> Â Â Â default: >> Â Â Â Â Â Â Â ret = -EINVAL; >> Â Â Â } > > Mmm ... what if I open /dev/sdxyz and call fadvise() on it? ÂI think > you end up flushing /dev's page cache entries, instead of the filesystem > which is on /dev/sdxyz. i was thinking of that, but was trying to come up with situations where there might not have a node to work on. fs's in a file go through loop devs, dm/lvm have ones created, and flash fs's still have a mtd block. how about network based fs's ? how you going to signal dropping of pages for nfs or cifs or fuse ones ? -mike -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
