> -----Original Message----- > From: Benny Halevy [mailto:bhalevy@xxxxxxxxxx] > Sent: Thursday, November 10, 2011 5:21 PM > To: Peng Tao > Cc: linux-nfs@xxxxxxxxxxxxxxx; Trond.Myklebust@xxxxxxxxxx; Peng, Tao > Subject: Re: [PATCH 7/8] pnfsblock: add im_extents to pnfs_inval_markings > > On 2011-11-10 10:54, Benny Halevy wrote: > > On 2011-11-09 17:16, Peng Tao wrote: > >> It stores a list of short extents for INVAL->RW conversion. > >> Also add two functions to manipulate them, in preparation to > >> move malloc logic out of end_io. > >> > >> Signed-off-by: Peng Tao <peng_tao@xxxxxxx> > >> --- > >> fs/nfs/blocklayout/blocklayout.c | 6 ++++++ > >> fs/nfs/blocklayout/blocklayout.h | 5 +++++ > >> fs/nfs/blocklayout/extents.c | 37 > +++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 48 insertions(+), 0 deletions(-) > >> > >> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c > >> index 815c0c3..cb4ff0f 100644 > >> --- a/fs/nfs/blocklayout/blocklayout.c > >> +++ b/fs/nfs/blocklayout/blocklayout.c > >> @@ -706,11 +706,17 @@ static void > >> release_inval_marks(struct pnfs_inval_markings *marks) > >> { > >> struct pnfs_inval_tracking *pos, *temp; > >> + struct pnfs_block_short_extent *se, *stemp; > >> > >> list_for_each_entry_safe(pos, temp, &marks->im_tree.mtt_stub, it_link) { > >> list_del(&pos->it_link); > >> kfree(pos); > >> } > >> + > >> + list_for_each_entry_safe(se, stemp, &marks->im_extents, bse_node) { > >> + list_del(&se->bse_node); > >> + kfree(se); > >> + } > >> return; > >> } > >> > >> diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h > >> index 60728ac..df0e0fb 100644 > >> --- a/fs/nfs/blocklayout/blocklayout.h > >> +++ b/fs/nfs/blocklayout/blocklayout.h > >> @@ -70,6 +70,7 @@ struct pnfs_inval_markings { > >> spinlock_t im_lock; > >> struct my_tree im_tree; /* Sectors that need LAYOUTCOMMIT */ > >> sector_t im_block_size; /* Server blocksize in sectors */ > >> + struct list_head im_extents; /* List of short extents for INVAL->RW conversion > */ > >> }; > >> > >> struct pnfs_inval_tracking { > >> @@ -105,6 +106,7 @@ BL_INIT_INVAL_MARKS(struct pnfs_inval_markings > *marks, sector_t blocksize) > >> { > >> spin_lock_init(&marks->im_lock); > >> INIT_LIST_HEAD(&marks->im_tree.mtt_stub); > >> + INIT_LIST_HEAD(&marks->im_extents); > >> marks->im_block_size = blocksize; > >> marks->im_tree.mtt_step_size = min((sector_t)PAGE_CACHE_SECTORS, > >> blocksize); > >> @@ -200,5 +202,8 @@ int bl_add_merge_extent(struct pnfs_block_layout *bl, > >> struct pnfs_block_extent *new); > >> int bl_mark_for_commit(struct pnfs_block_extent *be, > >> sector_t offset, sector_t length); > >> +int bl_push_one_short_extent(struct pnfs_inval_markings *marks); > >> +struct pnfs_block_short_extent* > >> +bl_pop_short_extent(struct pnfs_inval_markings *marks, int num_to_pop); > >> > >> #endif /* FS_NFS_NFS4BLOCKLAYOUT_H */ > >> diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c > >> index 952ea8a..72c7fa1 100644 > >> --- a/fs/nfs/blocklayout/extents.c > >> +++ b/fs/nfs/blocklayout/extents.c > >> @@ -863,3 +863,40 @@ clean_pnfs_block_layoutupdate(struct > pnfs_block_layout *bl, > >> } > >> } > >> } > >> + > >> +int > >> +bl_push_one_short_extent(struct pnfs_inval_markings *marks) { > >> + struct pnfs_block_short_extent *new; > >> + > >> + new = kmalloc(sizeof(*new), GFP_NOFS); > >> + if (unlikely(!new)) > >> + return -ENOMEM; > >> + > >> + spin_lock(&marks->im_lock); > >> + list_add(&new->bse_node, &marks->im_extents); > >> + spin_unlock(&marks->im_lock); > >> + > >> + return 0; > >> +} > >> + > >> +struct pnfs_block_short_extent* > >> +bl_pop_short_extent(struct pnfs_inval_markings *marks, int num_to_pop) { > >> + struct pnfs_block_short_extent *rv = NULL; > > The use case for bl_pop_short_extent comes only in the next patch > so it should be introduced there in principle, along with its use. I was hoping not to create too large single patch... But since you asked, I will merge them into one. > > With that in mind, there is one call site with num_to_pop == 1 > in which you don't free any entry, and the other with num_to_pop == num_se > which seems to free all the members of the list, but the last one, > which is then freed by the caller. > > This tells me you crammed two functions into one and you better > have one that pops a single element and another to destroy the list. Good point. I thought there might be more users of the function when I first wrote it but apparently I am wrong... I will split it into bl_pop_one_short_extent() and bl_free_short_extents() as you suggested. Thank you very much! Tao > > Benny > > >> + > >> + if (unlikely(num_to_pop <= 0)) > >> + return rv; > > > > How unlikely is it? > > Is doing the extra compare really worth saving the spin_lock? > > > >> + > >> + spin_lock(&marks->im_lock); > >> + while (!list_empty(&marks->im_extents) && num_to_pop-- > 0) { > >> + rv = list_entry((&marks->im_extents)->next, > >> + struct pnfs_block_short_extent, bse_node); > >> + list_del_init(&rv->bse_node); > >> + if (num_to_pop) > >> + kfree(rv); > > > > Please correct me if I'm wrong, you don't want to free the last element > > you pop since you want to return it. This is worth a comment... > > > > I'd consider moving the decrement expression down here or > > changing the loop to be a for loop to improve its readability. > > In the latter case this will say if (num_to_pop > 1) kfree(rv) > > which is more straight forward IMHO. > > > > Benny > > > >> + } > >> + spin_unlock(&marks->im_lock); > >> + > >> + BUG_ON(num_to_pop > 0); > >> + > >> + return rv; > >> +} -- 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
