lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Thu,  7 Mar 2019 17:25:54 +0100
From:   Paolo Valente <paolo.valente@...aro.org>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        ulf.hansson@...aro.org, linus.walleij@...aro.org,
        broonie@...nel.org, bfq-iosched@...glegroups.com,
        oleksandr@...alenko.name, fra.fra.800@...il.com,
        Paolo Valente <paolo.valente@...aro.org>
Subject: [PATCH BUGFIX IMPROVEMENT 8/8] block, bfq: save & resume weight on a queue merge/split

From: Francesco Pollicino <fra.fra.800@...il.com>

bfq saves the state of a queue each time a merge occurs, to be
able to resume such a state when the queue is associated again
with its original process, on a split.

Unfortunately bfq does not save & restore also the weight of the
queue. If the weight is not correctly resumed when the queue is
recycled, then the weight of the recycled queue could differ
from the weight of the original queue.

This commit adds the missing save & resume of the weight.

Signed-off-by: Francesco Pollicino <fra.fra.800@...il.com>
Signed-off-by: Paolo Valente <paolo.valente@...aro.org>
---
 block/bfq-iosched.c | 2 ++
 block/bfq-iosched.h | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 7d95d9c01036..1712d12340c0 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1028,6 +1028,7 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd,
 	else
 		bfq_clear_bfqq_IO_bound(bfqq);
 
+	bfqq->entity.new_weight = bic->saved_weight;
 	bfqq->ttime = bic->saved_ttime;
 	bfqq->wr_coeff = bic->saved_wr_coeff;
 	bfqq->wr_start_at_switch_to_srt = bic->saved_wr_start_at_switch_to_srt;
@@ -2502,6 +2503,7 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq)
 	if (!bic)
 		return;
 
+	bic->saved_weight = bfqq->entity.orig_weight;
 	bic->saved_ttime = bfqq->ttime;
 	bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq);
 	bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 21ddb19cc322..18cc0e996abf 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -404,6 +404,15 @@ struct bfq_io_cq {
 	 */
 	bool was_in_burst_list;
 
+	/*
+	 * Save the weight when a merge occurs, to be able
+	 * to restore it in case of split. If the weight is not
+	 * correctly resumed when the queue is recycled,
+	 * then the weight of the recycled queue could differ
+	 * from the weight of the original queue.
+	 */
+	unsigned int saved_weight;
+
 	/*
 	 * Similar to previous fields: save wr information.
 	 */
-- 
2.20.1

Powered by blists - more mailing lists