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[207.38.238.8]) by mx.google.com with ESMTPSA id n20sm8504159qgd.48.2015.03.22.21.55.40 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 22 Mar 2015 21:55:40 -0700 (PDT) From: Tejun Heo To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com, fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com, Tejun Heo Subject: [PATCH 19/48] bdi: separate out congested state into a separate struct Date: Mon, 23 Mar 2015 00:54:30 -0400 Message-Id: <1427086499-15657-20-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1427086499-15657-1-git-send-email-tj@kernel.org> References: <1427086499-15657-1-git-send-email-tj@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, a wb's (bdi_writeback) congestion state is carried in its ->state field; however, cgroup writeback support will require multiple wb's sharing the same congestion state. This patch separates out congestion state into its own struct - struct bdi_writeback_congested. A new field wb field, wb_congested, points to its associated congested struct. The default wb, bdi->wb, always points to bdi->wb_congested. While this patch adds a layer of indirection, it doesn't introduce any behavior changes. Signed-off-by: Tejun Heo --- include/linux/backing-dev-defs.h | 14 ++++++++++++-- include/linux/backing-dev.h | 2 +- mm/backing-dev.c | 7 +++++-- 3 files changed, 18 insertions(+), 5 deletions(-) diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index aa18c4b..9e9eafa 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -16,12 +16,15 @@ struct dentry; * Bits in bdi_writeback.state */ enum wb_state { - WB_async_congested, /* The async (write) queue is getting full */ - WB_sync_congested, /* The sync queue is getting full */ WB_registered, /* bdi_register() was done */ WB_writeback_running, /* Writeback is in progress */ }; +enum wb_congested_state { + WB_async_congested, /* The async (write) queue is getting full */ + WB_sync_congested, /* The sync queue is getting full */ +}; + typedef int (congested_fn)(void *, int); enum wb_stat_item { @@ -34,6 +37,10 @@ enum wb_stat_item { #define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) +struct bdi_writeback_congested { + unsigned long state; /* WB_[a]sync_congested flags */ +}; + struct bdi_writeback { struct backing_dev_info *bdi; /* our parent bdi */ @@ -48,6 +55,8 @@ struct bdi_writeback { struct percpu_counter stat[NR_WB_STAT_ITEMS]; + struct bdi_writeback_congested *congested; + unsigned long bw_time_stamp; /* last time write bw is updated */ unsigned long dirtied_stamp; unsigned long written_stamp; /* pages written at bw_time_stamp */ @@ -84,6 +93,7 @@ struct backing_dev_info { unsigned int max_ratio, max_prop_frac; struct bdi_writeback wb; /* default writeback info for this bdi */ + struct bdi_writeback_congested wb_congested; struct device *dev; diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 7857820..bfdaa18 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -167,7 +167,7 @@ static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) { if (bdi->congested_fn) return bdi->congested_fn(bdi->congested_data, bdi_bits); - return (bdi->wb.state & bdi_bits); + return (bdi->wb.congested->state & bdi_bits); } static inline int bdi_read_congested(struct backing_dev_info *bdi) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 805b287..5ec7658 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -383,6 +383,9 @@ int bdi_init(struct backing_dev_info *bdi) if (err) return err; + bdi->wb_congested.state = 0; + bdi->wb.congested = &bdi->wb_congested; + return 0; } EXPORT_SYMBOL(bdi_init); @@ -504,7 +507,7 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int sync) wait_queue_head_t *wqh = &congestion_wqh[sync]; bit = sync ? WB_sync_congested : WB_async_congested; - if (test_and_clear_bit(bit, &bdi->wb.state)) + if (test_and_clear_bit(bit, &bdi->wb.congested->state)) atomic_dec(&nr_bdi_congested[sync]); smp_mb__after_atomic(); if (waitqueue_active(wqh)) @@ -517,7 +520,7 @@ void set_bdi_congested(struct backing_dev_info *bdi, int sync) enum wb_state bit; bit = sync ? WB_sync_congested : WB_async_congested; - if (!test_and_set_bit(bit, &bdi->wb.state)) + if (!test_and_set_bit(bit, &bdi->wb.congested->state)) atomic_inc(&nr_bdi_congested[sync]); } EXPORT_SYMBOL(set_bdi_congested);