From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Whitehouse Date: Fri, 14 Sep 2007 17:50:16 +0100 Subject: [Cluster-devel] [PATCH] [GFS2] bz253089 Make gfs2_writepage use trylock on the log_flush lock In-Reply-To: <20070913163622.GC5841@ether.msp.redhat.com> References: <20070913163037.GB5841@ether.msp.redhat.com> <20070913163622.GC5841@ether.msp.redhat.com> Message-ID: <1189788616.1068.65.camel@quoit> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi, On Thu, 2007-09-13 at 11:36 -0500, Benjamin Marzinski wrote: > On Thu, Sep 13, 2007 at 11:30:37AM -0500, Benjamin Marzinski wrote: > > gfs2 was deadlocking because most code paths acquire the sd_log_flush_lock and > > then the page locks, while code paths going through gfs2_writepage acquire the > > page locks and then the log flush lock. > > > > This patch makes gfs2_writepage do a trylock on the sd_log_flush_lock. If it > > fails, writepage simply redirtys the page and gives up. This should keep the > > deadlock from happening, however it might cause a performance hit. > > > > Signed-off-by: Benjamin E. Marzinski > > And here is the actual patch > Now in the -nmw git tree. Thanks, Steve. > plain text document attachment (253089_try4.patch) > diff -urpN --exclude-from=linux-2.6.18-44.gfs2abhi.003_test_clean/Documentation/dontdiff linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/log.c linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/log.c > --- linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/log.c 2007-09-05 09:33:11.000000000 -0500 > +++ linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/log.c 2007-09-11 10:03:48.000000000 -0500 > @@ -288,7 +288,7 @@ static void ail2_empty(struct gfs2_sbd * > * Returns: errno > */ > > -int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks) > +int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks, int wait) > { > unsigned int try = 0; > unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize); > @@ -301,6 +301,10 @@ int gfs2_log_reserve(struct gfs2_sbd *sd > gfs2_log_lock(sdp); > while(sdp->sd_log_blks_free <= (blks + reserved_blks)) { > gfs2_log_unlock(sdp); > + if (!wait) { > + mutex_unlock(&sdp->sd_log_reserve_mutex); > + return -EBUSY; > + } > gfs2_ail1_empty(sdp, 0); > gfs2_log_flush(sdp, NULL); > > @@ -310,10 +314,21 @@ int gfs2_log_reserve(struct gfs2_sbd *sd > } > sdp->sd_log_blks_free -= blks; > gfs2_log_unlock(sdp); > - mutex_unlock(&sdp->sd_log_reserve_mutex); > - > - down_read(&sdp->sd_log_flush_lock); > > + if (wait){ > + mutex_unlock(&sdp->sd_log_reserve_mutex); > + down_read(&sdp->sd_log_flush_lock); > + } > + else { > + if (!down_read_trylock(&sdp->sd_log_flush_lock)) { > + gfs2_log_lock(sdp); > + sdp->sd_log_blks_free += blks; > + gfs2_log_unlock(sdp); > + mutex_unlock(&sdp->sd_log_reserve_mutex); > + return -EBUSY; > + } > + mutex_unlock(&sdp->sd_log_reserve_mutex); > + } > return 0; > } > > diff -urpN --exclude-from=linux-2.6.18-44.gfs2abhi.003_test_clean/Documentation/dontdiff linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/log.h linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/log.h > --- linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/log.h 2007-08-29 14:11:37.000000000 -0500 > +++ linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/log.h 2007-09-09 08:18:08.000000000 -0500 > @@ -50,7 +50,7 @@ unsigned int gfs2_struct2blk(struct gfs2 > > int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags); > > -int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks); > +int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks, int wait); > void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks); > > struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp); > diff -urpN --exclude-from=linux-2.6.18-44.gfs2abhi.003_test_clean/Documentation/dontdiff linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/ops_address.c linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/ops_address.c > --- linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/ops_address.c 2007-08-29 14:11:37.000000000 -0500 > +++ linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/ops_address.c 2007-09-09 08:20:50.000000000 -0500 > @@ -140,7 +140,7 @@ static int gfs2_writepage(struct page *p > if ((sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) && > PageChecked(page)) { > ClearPageChecked(page); > - error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0); > + error = gfs2_do_trans_begin(sdp, RES_DINODE + 1, 0, 0); > if (error) > goto out_ignore; > if (!page_has_buffers(page)) { > diff -urpN --exclude-from=linux-2.6.18-44.gfs2abhi.003_test_clean/Documentation/dontdiff linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/trans.c linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/trans.c > --- linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/trans.c 2007-09-04 07:45:25.000000000 -0500 > +++ linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/trans.c 2007-09-09 09:23:05.000000000 -0500 > @@ -25,8 +25,8 @@ > #include "trans.h" > #include "util.h" > > -int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks, > - unsigned int revokes) > +int gfs2_do_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks, > + unsigned int revokes, int wait) > { > struct gfs2_trans *tr; > int error; > @@ -61,7 +61,7 @@ int gfs2_trans_begin(struct gfs2_sbd *sd > goto fail_gunlock; > } > > - error = gfs2_log_reserve(sdp, tr->tr_reserved); > + error = gfs2_log_reserve(sdp, tr->tr_reserved, wait); > if (error) > goto fail_gunlock; > > diff -urpN --exclude-from=linux-2.6.18-44.gfs2abhi.003_test_clean/Documentation/dontdiff linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/trans.h linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/trans.h > --- linux-2.6.18-44.gfs2abhi.003_test_clean/fs/gfs2/trans.h 2007-09-04 07:45:25.000000000 -0500 > +++ linux-2.6.18-44.gfs2abhi.003_test/fs/gfs2/trans.h 2007-09-09 08:21:29.000000000 -0500 > @@ -25,8 +25,8 @@ struct gfs2_glock; > #define RES_STATFS 1 > #define RES_QUOTA 2 > > -int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks, > - unsigned int revokes); > +int gfs2_do_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks, > + unsigned int revokes, int wait); > > void gfs2_trans_end(struct gfs2_sbd *sdp); > > @@ -36,4 +36,11 @@ void gfs2_trans_add_revoke(struct gfs2_s > void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno); > void gfs2_trans_add_rg(struct gfs2_rgrpd *rgd); > > + > +static inline int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks, > + unsigned int revokes) > +{ > + return gfs2_do_trans_begin(sdp, blocks, revokes, 1); > +} > + > #endif /* __TRANS_DOT_H__ */