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Subject: RE:(2) [PATCH 0/4] zstd: reduce stack usage
Reply-To: v.narang@samsung.com
From:   Vaneet Narang <v.narang@samsung.com>
To:     Andrew Morton <akpm@linux-foundation.org>,
        Maninder Singh <maninder1.s@samsung.com>
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        "gustavo@embeddedor.com" <gustavo@embeddedor.com>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        AMIT SAHRAWAT <a.sahrawat@samsung.com>,
        PANKAJ MISHRA <pankaj.m@samsung.com>,
        Vaneet Narang <v.narang@samsung.com>
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Message-ID: <20190604120623epcms5p3fc13e98047e7b44d6da144425213b4fe@epcms5p3>
Date:   Tue, 04 Jun 2019 17:36:23 +0530
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Hi Andrew,

>> This patch set reduces stack usage for zstd code, because target like AR=
M has
>> limited 8KB kernel stack, which is getting overflowed due to hight stack=
 usage
>> of zstd code with call flow like:
=20
>That's rather bad behaviour.  I assume the patchset actually fixes this?

Yes, patchset tries to reduce around 300 bytes of stack usage of zstd compr=
ession path.=20
We faced high stack usage issue on switching compression algo from LZO/LZ4 =
to zstd algo.
zstd compression uses around 1200 bytes of stack which is huge as compared=
=20
to LZO/LZ4 which uses negligible stack (< 200 bytes).

=20
>I think I'll schedule the patchset for 5.2-rcX so that zstd is actually
>usable on arm in 5.2.  Does that sound OK?=C2=A0=0D=0AOK=0D=0A=0D=0ARegard=
s,=0D=0AVaneet=20Narang=0D=0A