Messages in this thread | | | From | "Zach O'Keefe" <> | Date | Mon, 24 Oct 2022 09:44:16 -0700 | Subject | Re: [PATCH] mm/khugepaged: add tracepoint to collapse_file() |
| |
Thanks for your mail, Gautam.
> I try to keep dereferences out of the calling path as much as possible > (adds to I$ at the call site).
This was probably due to the way I handled trace_mm_khugepaged_scan_file(). Perhaps that can be cleaned up at the same time as this patch, for consistency.
Also, no qualms about adding this tracepoint; there are a few scan result codes that overlap between hpage_collapse_scan_file() and those possibly returned in collapse_file() such that, if we only have the one tracepoint in hpage_collapse_scan_file(), it could be ambiguous what callsite the error path stemmed from. Luckily this hasn't been an issue thus far.
Lastly, a few other items we might care about capturing:
- is_shmem (perhaps the filename is enough to know this - but I know at least once during development I was caught off-guard b/c a mount I thought to be file-backed turned out to be tmpfs (and something I didn't think to question until I had wasted some time on other paths)). - index
Best, Zach
> Could you just pass in file, and then have: > > __string(filename, file->f_path.dentry->d_iname) > > [..] > > __assign_string(filename, file->f_path.dentry->d_iname); > > > If you are paranoid, you can have the above also be: > > file ? file->f_path.dentry ? file->f_path.dentry->d_iname : "(null)" : "(null)") > > > -- Steve > > > > + nr, result); > > return result;
| |