On Thu, Jul 16, 2009 at 10:17:48AM -0400, J. Bruce Fields wrote:
> On Wed, Jun 24, 2009 at 03:37:46PM -0400, andros@xxxxxxxxxx wrote:
> > From: Andy Adamson <andros@xxxxxxxxxx>
> >
> > NFSD_SLOT_CACHE_SIZE is the size of all encoded operation responses (excluding
> > the sequence operation) that we want to cache.
> >
> > Adjust NFSD_DRC_SIZE_SHIFT to reflect using 512 bytes instead of PAGE_SIZE.
> >
> > Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
> > ---
> > fs/nfsd/nfs4state.c | 30 ++++++++++++++----------------
> > fs/nfsd/nfssvc.c | 17 +++++++++--------
> > include/linux/nfsd/nfsd.h | 4 ++--
> > include/linux/nfsd/state.h | 1 +
> > 4 files changed, 26 insertions(+), 26 deletions(-)
> >
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 2e6a44e..b4a536d 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -414,35 +414,33 @@ gen_sessionid(struct nfsd4_session *ses)
> >
> > /*
> > * Give the client the number of slots it requests bound by
> > - * NFSD_MAX_SLOTS_PER_SESSION and by sv_drc_max_pages.
> > + * NFSD_MAX_SLOTS_PER_SESSION and by nfsd_drc_max_mem.
> > *
> > - * If we run out of pages (sv_drc_pages_used == sv_drc_max_pages) we
> > - * should (up to a point) re-negotiate active sessions and reduce their
> > - * slot usage to make rooom for new connections. For now we just fail the
> > - * create session.
> > + * If we run out of reserved DRC memory we should (up to a point) re-negotiate
> > + * active sessions and reduce their slot usage to make rooom for new
> > + * connections. For now we just fail the create session.
> > */
> > static int set_forechannel_maxreqs(struct nfsd4_channel_attrs *fchan)
> > {
> > - int status = 0, np = fchan->maxreqs * NFSD_PAGES_PER_SLOT;
> > + int mem;
> >
> > if (fchan->maxreqs < 1)
> > return nfserr_inval;
> > else if (fchan->maxreqs > NFSD_MAX_SLOTS_PER_SESSION)
> > fchan->maxreqs = NFSD_MAX_SLOTS_PER_SESSION;
> >
> > + mem = fchan->maxreqs * NFSD_SLOT_CACHE_SIZE;
> > +
> > spin_lock(&nfsd_drc_lock);
> > - if (np + nfsd_drc_pages_used > nfsd_drc_max_pages)
> > - np = nfsd_drc_max_pages - nfsd_drc_pages_used;
> > - nfsd_drc_pages_used += np;
> > + if (mem + nfsd_drc_mem_used > nfsd_drc_max_mem)
> > + mem = nfsd_drc_max_mem - nfsd_drc_mem_used;
> > + nfsd_drc_mem_used += mem;
>
> There's a small bug here: in the case where
>
> 0 < mem < NFSD_PAGES_PER_SLOT,
>
> we add mem into nfsd_drc_mem_used, but never subtract it back off.
(Actually this is true whenever there's roundoff error, since we're
adding in the un-rounded-off version but subtracting off (in the next
patch) the rounded-off version.)
--b.
>
> > spin_unlock(&nfsd_drc_lock);
> >
> > - if (np <= 0) {
> > - status = nfserr_resource;
> > - fchan->maxreqs = 0;
> > - } else
> > - fchan->maxreqs = np / NFSD_PAGES_PER_SLOT;
> > -
> > - return status;
> > + fchan->maxreqs = mem / NFSD_SLOT_CACHE_SIZE;
> > + if (fchan->maxreqs == 0)
> > + return nfserr_resource;
> > + return 0;
> > }
> >
> > /*
> > diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> > index 78d8fcd..1793dba 100644
> > --- a/fs/nfsd/nfssvc.c
> > +++ b/fs/nfsd/nfssvc.c
> > @@ -74,8 +74,8 @@ struct svc_serv *nfsd_serv;
> > * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
> > */
> > spinlock_t nfsd_drc_lock;
> > -unsigned int nfsd_drc_max_pages;
> > -unsigned int nfsd_drc_pages_used;
> > +unsigned int nfsd_drc_max_mem;
> > +unsigned int nfsd_drc_mem_used;
> >
> > #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
> > static struct svc_stat nfsd_acl_svcstats;
> > @@ -247,13 +247,14 @@ void nfsd_reset_versions(void)
> > static void set_max_drc(void)
> > {
> > /* The percent of nr_free_buffer_pages used by the V4.1 server DRC */
> > - #define NFSD_DRC_SIZE_SHIFT 7
> > - nfsd_drc_max_pages = nr_free_buffer_pages()
> > - >> NFSD_DRC_SIZE_SHIFT;
> > - nfsd_drc_pages_used = 0;
> > + #define NFSD_DRC_SIZE_SHIFT 10
> > + nfsd_drc_max_mem = (nr_free_buffer_pages()
> > + >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
> > + nfsd_drc_mem_used = 0;
> > spin_lock_init(&nfsd_drc_lock);
> > - dprintk("%s nfsd_drc_max_pages %u\n", __func__,
> > - nfsd_drc_max_pages);
> > + dprintk("%s nfsd_drc_max_mem %u [in pages %lu]\n", __func__,
> > + nfsd_drc_max_mem,
> > + nfsd_drc_max_mem / PAGE_SIZE);
>
> The reader can do the "in pages" for him/herself if necessary.
>
> > }
> >
> > int nfsd_create_serv(void)
> > diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
> > index 2571f85..2812ed5 100644
> > --- a/include/linux/nfsd/nfsd.h
> > +++ b/include/linux/nfsd/nfsd.h
> > @@ -57,8 +57,8 @@ extern u32 nfsd_supported_minorversion;
> > extern struct mutex nfsd_mutex;
> > extern struct svc_serv *nfsd_serv;
> > extern spinlock_t nfsd_drc_lock;
> > -extern unsigned int nfsd_drc_max_pages;
> > -extern unsigned int nfsd_drc_pages_used;
> > +extern unsigned int nfsd_drc_max_mem;
> > +extern unsigned int nfsd_drc_mem_used;
> >
> > extern struct seq_operations nfs_exports_op;
> >
> > diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
> > index f5a95fd..10b6b30 100644
> > --- a/include/linux/nfsd/state.h
> > +++ b/include/linux/nfsd/state.h
> > @@ -98,6 +98,7 @@ struct nfs4_cb_conn {
> > /* Maximum number of pages per slot cache entry */
> > #define NFSD_PAGES_PER_SLOT 1
> > /* Maximum number of operations per session compound */
> > +#define NFSD_SLOT_CACHE_SIZE 512
>
> Whoops--the above comment's misplaced now.
>
> Also, this patch leaves the code in an inconsistent state where some
> places still uses page size, others don't. (E.g. we promise to cache
> page_size, and still will, I think, and allocate that much, but we
> calculate the maximum requests by the new smaller 512 byte value.)
>
> Either fix all that at once, or just keep NFSD_SLOT_CACHE_SIZE 4k for
> now.
>
> --b.
>
> > #define NFSD_MAX_OPS_PER_COMPOUND 16
> >
> > struct nfsd4_cache_entry {
> > --
> > 1.5.4.3
> >
> > _______________________________________________
> > pNFS mailing list
> > pNFS@xxxxxxxxxxxxx
> > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
