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Mercier" , Martin Liu , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: vmscan: abort proactive reclaim early when freezing for suspend Message-ID: References: <20260709072231.3163082-1-richardycc@google.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Mimecast-MFC-PROC-ID: lSd_tpm8-U3O6iDAr_IlvVYnuBgphoeACdNJ_0Czo3E_1784137667 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: AFEED20006 X-Stat-Signature: eyc1gdyizxsu3x8aodjgqyuxz3i995ny X-HE-Tag: 1784137676-373843 X-HE-Meta: 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 uFqIgayR 61g2nIe8+kwkhHCx2j34NhKZXzTKTqsI8Sziinp+pF9TswqAfSiiD7wI+U5oeyoHp5SbD5e3TwS5bZq5WV3IHXjKb2vcOx5KDcdKxWuNK0fVd8+tq7nVKeAq6h4++NVb0l6u/RGJeFHQRHS6+hvJq/KkhWOPSOU8Ef2Lt6SMkv1aIW3gG3XW6KzGh240j35lBOMvD/s92DeKRKUh36lwgh0pmYXwL/Qj7SQSl6UjTarqChStzatj6rd06HmdIemkdeJiQJ78OmTrbXBhUaBkDCVIg4JpoFmgCqE1pZq3SX+qUpv+JtiL6VdcAh0AwspWgT5vVoEVEXM73ejfWnb5eE2vIt4mcjORceitB Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Michal, On 07/15, Michal Hocko wrote: > > Oleg you haven't been CCed from the top of the thread but TL;DR is that > we need to freeze a user task performing pro-active memory reclaim that > might take long. Currently we are calling signal_pending to bail out > but that leaks EINTR which is bad as freezing task has a side effect of > terminating it. Sorry, I guess I don't understand the problem... Yes, unlike EINTR, ERESTARTSYS should not leak to the caller (just in case, debugger can see this error code). But I am sure you know this. And the patch looks fine to me. Oleg. > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 35c3bb15ae96..336af76d2a28 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -7909,8 +7909,13 @@ int user_proactive_reclaim(char *buf, > unsigned long batch_size = (nr_to_reclaim - nr_reclaimed) / 4; > unsigned long reclaimed; > > + /* > + * Make sure that we enter freezer without delaying much and > + * leaking EINTR when that happens but also take care of > + * fatal signals to terminate. > + */ > if (signal_pending(current)) > - return -EINTR; > + return -ERESTARTSYS; > > /* > * This is the final attempt, drain percpu lru caches in the > -- > Michal Hocko > SUSE Labs >