On Thu, Jan 11, 2018 at 01:37:36PM -0600, Eric Sandeen wrote: > Fake up the xfs_buf_zone allocated count a bit to account > for buffers freed to and allocated from cache. > > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxxx> > --- > libxfs/rdwr.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/libxfs/rdwr.c b/libxfs/rdwr.c > index 474e5eb..c5ffd4d 100644 > --- a/libxfs/rdwr.c > +++ b/libxfs/rdwr.c > @@ -665,6 +665,7 @@ __libxfs_getbufr(int blen) > free(bp->b_maps); > bp->b_maps = NULL; > } > + xfs_buf_zone->allocated++; I'm confused. kmem_zone_zalloc increments zone->allocated and kmem_zone_free decrements it. Now we're messing with ->allocated ourselves, which means that buffers that have ended up on xfs_buf_freelist are still allocated (according to the heap) but the zone accounting thinks the buffer is freed? <goes away, reviews the next patch, comes back> The next patch has xfs_buf_freelist frees the buffer directly and bypassing kmem_zone_free. So I wonder, if you change the next patch to call kmem_zone_free and kill this patch, won't the accounting work out? (xfs buf zone allocated == 0) bp = _zone_alloc() xfs_buf_zone->allocated++ ...do stuff with buffer... xfs_buf_relse(bp) list_add(bp, xfs_buf_freelist) ...buffer still allocated, xfs_buf_zone->allocated == 1... libxfs_bcache_free() _zone_free(bp) xfs_buf_zone->allocated-- ...exit program, and: xfs_buf_zone->allocated == 0 I think killing this patch and teaching the next one to kmem_zone_free the buffer works, right? Or am I missing some subtlety here, in which case said subtlety needs comments. --D > } else > bp = kmem_zone_zalloc(xfs_buf_zone, 0); > pthread_mutex_unlock(&xfs_buf_freelist.cm_mutex); > @@ -1245,6 +1246,7 @@ libxfs_brelse( > "releasing dirty buffer to free list!"); > > pthread_mutex_lock(&xfs_buf_freelist.cm_mutex); > + xfs_buf_zone->allocated--; > list_add(&bp->b_node.cn_mru, &xfs_buf_freelist.cm_list); > pthread_mutex_unlock(&xfs_buf_freelist.cm_mutex); > } > @@ -1268,6 +1270,7 @@ libxfs_bulkrelse( > } > > pthread_mutex_lock(&xfs_buf_freelist.cm_mutex); > + xfs_buf_zone->allocated -= count; > list_splice(list, &xfs_buf_freelist.cm_list); > pthread_mutex_unlock(&xfs_buf_freelist.cm_mutex); > > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" 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-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
