linux-kernel - RE: amusing SLUB compaction bug when CC_OPTIMIZE_FOR

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Message-ID: <c1c8920a56014a179dbb82d483f2ad28@AcuMS.aculab.com>
Date:   Fri, 30 Sep 2022 11:02:38 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Hugh Dickins' <hughd@...gle.com>, Vlastimil Babka <vbabka@...e.cz>
CC:     Joel Fernandes <joel@...lfernandes.org>,
        Hyeonggon Yoo <42.hyeyoo@...il.com>,
        Matthew Wilcox <willy@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: RE: amusing SLUB compaction bug when CC_OPTIMIZE_FOR_SIZE

> > > Regarding "conflicting" alignment requests: yes, I agree with you,
> > > it would have to be a toolchain bug if when asked to align 2 and to
> > > align 4, it chose not to align 4.

See https://godbolt.org/z/3nGsTaf5e
the align() directive takes precedence.

Here you only want to ensure the alignment is at least 4.

	David

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