From: Johannes Weiner <hannes@cmpxchg.org>
To: Song Liu <songliubraving@fb.com>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, matthew.wilcox@oracle.com,
kirill.shutemov@linux.intel.com, kernel-team@fb.com,
william.kucharski@oracle.com, akpm@linux-foundation.org,
hdanton@sina.com
Subject: Re: [PATCH v10 6/7] mm,thp: add read-only THP support for (non-shmem) FS
Date: Mon, 12 Aug 2019 16:36:14 -0400 [thread overview]
Message-ID: <20190812203614.GB15498@cmpxchg.org> (raw)
In-Reply-To: <20190801184244.3169074-7-songliubraving@fb.com>
On Thu, Aug 01, 2019 at 11:42:43AM -0700, Song Liu wrote:
> This patch is (hopefully) the first step to enable THP for non-shmem
> filesystems.
>
> This patch enables an application to put part of its text sections to THP
> via madvise, for example:
>
> madvise((void *)0x600000, 0x200000, MADV_HUGEPAGE);
>
> We tried to reuse the logic for THP on tmpfs.
>
> Currently, write is not supported for non-shmem THP. khugepaged will only
> process vma with VM_DENYWRITE. sys_mmap() ignores VM_DENYWRITE requests
> (see ksys_mmap_pgoff). The only way to create vma with VM_DENYWRITE is
> execve(). This requirement limits non-shmem THP to text sections.
>
> The next patch will handle writes, which would only happen when the all
> the vmas with VM_DENYWRITE are unmapped.
>
> An EXPERIMENTAL config, READ_ONLY_THP_FOR_FS, is added to gate this
> feature.
>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Acked-by: Rik van Riel <riel@surriel.com>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
next prev parent reply other threads:[~2019-08-12 20:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 18:42 [PATCH v10 0/7] Enable THP for text section of non-shmem files Song Liu
2019-08-01 18:42 ` [PATCH v10 1/7] filemap: check compound_head(page)->mapping in filemap_fault() Song Liu
2019-08-01 18:42 ` [PATCH v10 2/7] filemap: check compound_head(page)->mapping in pagecache_get_page() Song Liu
2019-08-12 20:33 ` Johannes Weiner
2019-08-01 18:42 ` [PATCH v10 3/7] filemap: update offset check in filemap_fault() Song Liu
2019-08-01 18:42 ` [PATCH v10 4/7] mm,thp: stats for file backed THP Song Liu
2019-08-01 18:42 ` [PATCH v10 5/7] khugepaged: rename collapse_shmem() and khugepaged_scan_shmem() Song Liu
2019-08-01 18:42 ` [PATCH v10 6/7] mm,thp: add read-only THP support for (non-shmem) FS Song Liu
2019-08-12 20:36 ` Johannes Weiner [this message]
2019-08-01 18:42 ` [PATCH v10 7/7] mm,thp: avoid writes to file with THP in pagecache Song Liu
2019-08-12 20:38 ` Johannes Weiner
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