From: David Sterba <dsterba@suse.cz>
To: Eduard Shishkin <edward6@linux.ibm.com>
Cc: dsterba@suse.cz, Mikhail Zaslonko <zaslonko@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
Richard Purdie <rpurdie@rpsys.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Ilya Leoshkevich <iii@linux.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/6] btrfs: Use larger zlib buffer for s390 hardware compression
Date: Tue, 7 Jan 2020 15:30:59 +0100 [thread overview]
Message-ID: <20200107143058.GU3929@twin.jikos.cz> (raw)
In-Reply-To: <664c2bbd-e06f-a4b3-fe21-982954b6330c@linux.ibm.com>
On Tue, Jan 07, 2020 at 01:18:06AM +0100, Eduard Shishkin wrote:
> >> @@ -61,7 +64,17 @@ struct list_head *zlib_alloc_workspace(unsigned int level)
> >> zlib_inflate_workspacesize());
> >> workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
> >> workspace->level = level;
> >> - workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
> >> + workspace->buf = NULL;
> >> + if (zlib_deflate_dfltcc_enabled()) {
> >> + workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
> >> + __GFP_NOMEMALLOC | __GFP_NORETRY |
> >> + __GFP_NOWARN | GFP_NOIO);
> > Why do you use this wild GFP flag combination? I can understand NOWARN,
> > but why the others?
>
> This addresses the following complaint about order 2 allocation with
> GFP_KERNEL:
> https://lkml.org/lkml/2019/11/26/417
>
> Below a fallback to a single page is implemented, as it was suggested.
> So, the initial (more costly) allocation should be made with minimal
> aggression
> to allow the allocator fail. Otherwise, that fallback simply doesn't
> make sense.
> Hence, such a combination.
I see, please add a comment explaining that.
next prev parent reply other threads:[~2020-01-07 14:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-03 22:33 [PATCH v3 0/6] S390 hardware support for kernel zlib Mikhail Zaslonko
2020-01-03 22:33 ` [PATCH v3 1/6] lib/zlib: Add s390 hardware support for kernel zlib_deflate Mikhail Zaslonko
2020-01-03 22:33 ` [PATCH v3 2/6] s390/boot: Rename HEAP_SIZE due to name collision Mikhail Zaslonko
2020-01-07 14:50 ` Christian Borntraeger
2020-01-03 22:33 ` [PATCH v3 3/6] lib/zlib: Add s390 hardware support for kernel zlib_inflate Mikhail Zaslonko
2020-01-03 22:33 ` [PATCH v3 4/6] s390/boot: Add dfltcc= kernel command line parameter Mikhail Zaslonko
2020-01-03 22:33 ` [PATCH v3 5/6] lib/zlib: Add zlib_deflate_dfltcc_enabled() function Mikhail Zaslonko
2020-01-03 22:33 ` [PATCH v3 6/6] btrfs: Use larger zlib buffer for s390 hardware compression Mikhail Zaslonko
2020-01-06 16:40 ` Josef Bacik
2020-01-07 10:30 ` Zaslonko Mikhail
2020-01-06 18:43 ` David Sterba
2020-01-07 0:18 ` Eduard Shishkin
2020-01-07 14:30 ` David Sterba [this message]
2020-01-08 10:51 ` [PATCH v4] " Mikhail Zaslonko
2020-01-08 15:08 ` Josef Bacik
2020-01-08 18:48 ` Zaslonko Mikhail
2020-01-09 1:10 ` David Sterba
2020-01-13 10:03 ` Zaslonko Mikhail
2020-01-14 16:19 ` David Sterba
2020-01-14 16:18 ` David Sterba
2020-01-15 9:54 ` Fwd: " Zaslonko Mikhail
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