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Date:   Sun, 29 Oct 2023 23:32:07 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Daniel Gomez <da.gomez@samsung.com>
Cc:     "minchan@kernel.org" <minchan@kernel.org>,
        "senozhatsky@chromium.org" <senozhatsky@chromium.org>,
        "axboe@kernel.dk" <axboe@kernel.dk>,
        "djwong@kernel.org" <djwong@kernel.org>,
        "hughd@google.com" <hughd@google.com>,
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        "mcgrof@kernel.org" <mcgrof@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "gost.dev@samsung.com" <gost.dev@samsung.com>,
        Pankaj Raghav <p.raghav@samsung.com>
Subject: Re: [RFC PATCH 10/11] shmem: add large folio support to the write
 path
Message-ID: <ZT7rd3CSr+VnKj7v@casper.infradead.org>
References: <20230919135536.2165715-1-da.gomez@samsung.com>
 <20231028211518.3424020-1-da.gomez@samsung.com>
 <CGME20231028211551eucas1p1552b7695f12c27f4ea1b92ecb6259b31@eucas1p1.samsung.com>
 <20231028211518.3424020-11-da.gomez@samsung.com>
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In-Reply-To: <20231028211518.3424020-11-da.gomez@samsung.com>
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On Sat, Oct 28, 2023 at 09:15:50PM +0000, Daniel Gomez wrote:
> +++ b/mm/shmem.c
> @@ -1621,6 +1621,9 @@ static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info,
>  	pgoff_t ilx;
>  	struct page *page;
>  
> +	if ((order != 0) && !(gfp & VM_HUGEPAGE))
> +		gfp |= __GFP_COMP;

This is silly.  Just set it unconditionally.

> +static inline unsigned int
> +shmem_mapping_size_order(struct address_space *mapping, pgoff_t index,
> +			 size_t size, struct shmem_sb_info *sbinfo)
> +{
> +	unsigned int order = ilog2(size);
> +
> +	if ((order <= PAGE_SHIFT) ||
> +	    (!mapping_large_folio_support(mapping) || !sbinfo->noswap))
> +		return 0;
> +
> +	order -= PAGE_SHIFT;

You know we have get_order(), right?