| Message ID | 166429914973.4564.115423416224540586.stgit@manet.1015granger.net (mailing list archive) |
|---|---|
| Headers | show |
| Series | Replace file_hashtbl with an rhashtable | expand |
On Tue, 2022-09-27 at 13:22 -0400, Chuck Lever wrote: > Hi, while testing I noticed that sometimes thousands of items are > inserted into file_hashtbl, but it's a small fixed-size hash. That > makes the buckets in file_hashtbl larger than two or three items. > The comparison function (fh_match) used while walking through the > buckets is expensive and cache-unfriendly. > > The following patches seem to help alleviate that overhead. > > --- > > Chuck Lever (2): > NFSD: Use const pointers as parameters to fh_ helpers. > NFSD: Use rhashtable for managing nfs4_file objects > > > fs/nfsd/nfs4state.c | 227 ++++++++++++++++++++++++++++++-------------- > fs/nfsd/nfsfh.h | 10 +- > fs/nfsd/state.h | 5 +- > 3 files changed, 162 insertions(+), 80 deletions(-) > > -- > Chuck Lever > This set all looks reasonable to me, and I like the idea of moving to rhashtable. You can add: Reviewed-by: Jeff Layton <jlayton@kernel.org>
> On Sep 28, 2022, at 6:23 AM, Jeff Layton <jlayton@kernel.org> wrote: > > On Tue, 2022-09-27 at 13:22 -0400, Chuck Lever wrote: >> Hi, while testing I noticed that sometimes thousands of items are >> inserted into file_hashtbl, but it's a small fixed-size hash. That >> makes the buckets in file_hashtbl larger than two or three items. >> The comparison function (fh_match) used while walking through the >> buckets is expensive and cache-unfriendly. >> >> The following patches seem to help alleviate that overhead. >> >> --- >> >> Chuck Lever (2): >> NFSD: Use const pointers as parameters to fh_ helpers. >> NFSD: Use rhashtable for managing nfs4_file objects >> >> >> fs/nfsd/nfs4state.c | 227 ++++++++++++++++++++++++++++++-------------- >> fs/nfsd/nfsfh.h | 10 +- >> fs/nfsd/state.h | 5 +- >> 3 files changed, 162 insertions(+), 80 deletions(-) >> >> -- >> Chuck Lever >> > > This set all looks reasonable to me, and I like the idea of moving to > rhashtable. You can add: > > Reviewed-by: Jeff Layton <jlayton@kernel.org> Thanks for having a look. I'm not sure I want to push these as soon as v6.1, as they are quite fresh. That might increase the likelihood of collisions when you work on cleaning up stateID reference counting. -- Chuck Lever
Hi, while testing I noticed that sometimes thousands of items are inserted into file_hashtbl, but it's a small fixed-size hash. That makes the buckets in file_hashtbl larger than two or three items. The comparison function (fh_match) used while walking through the buckets is expensive and cache-unfriendly. The following patches seem to help alleviate that overhead. --- Chuck Lever (2): NFSD: Use const pointers as parameters to fh_ helpers. NFSD: Use rhashtable for managing nfs4_file objects fs/nfsd/nfs4state.c | 227 ++++++++++++++++++++++++++++++-------------- fs/nfsd/nfsfh.h | 10 +- fs/nfsd/state.h | 5 +- 3 files changed, 162 insertions(+), 80 deletions(-) -- Chuck Lever