From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id DFFB76B0006 for ; Fri, 16 Mar 2018 14:25:40 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id p9so5549645pfk.5 for ; Fri, 16 Mar 2018 11:25:40 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 64sor1188026pgj.144.2018.03.16.11.25.39 for (Google Transport Security); Fri, 16 Mar 2018 11:25:39 -0700 (PDT) From: Wei Wang Subject: [PATCH] mm: add config for readahead window Date: Fri, 16 Mar 2018 11:25:08 -0700 Message-Id: <20180316182512.118361-1-wvw@google.com> Sender: owner-linux-mm@kvack.org List-ID: Cc: gregkh@linuxfoundation.org, toddpoynor@google.com, wei.vince.wang@gmail.com, Wei Wang , Andrew Morton , Dan Williams , Michal Hocko , "Kirill A. Shutemov" , Jan Kara , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Hugh Dickins , Matthew Wilcox , Ingo Molnar , Sherry Cheung , Oliver O'Halloran , Andrey Ryabinin , Huang Ying , Dennis Zhou , Pavel Tatashin , linux-mm@kvack.org, linux-kernel@vger.kernel.org From: Wei Wang Change VM_MAX_READAHEAD value from the default 128KB to a configurable value. This will allow the readahead window to grow to a maximum size bigger than 128KB during boot, which could benefit to sequential read throughput and thus boot performance. Signed-off-by: Wei Wang --- include/linux/mm.h | 2 +- mm/Kconfig | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index ad06d42adb1a..d7dc6125833e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2291,7 +2291,7 @@ int __must_check write_one_page(struct page *page); void task_dirty_inc(struct task_struct *tsk); /* readahead.c */ -#define VM_MAX_READAHEAD 128 /* kbytes */ +#define VM_MAX_READAHEAD CONFIG_VM_MAX_READAHEAD_KB #define VM_MIN_READAHEAD 16 /* kbytes (includes current page) */ int force_page_cache_readahead(struct address_space *mapping, struct file *filp, diff --git a/mm/Kconfig b/mm/Kconfig index c782e8fb7235..da9ff543bdb9 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -760,3 +760,11 @@ config GUP_BENCHMARK performance of get_user_pages_fast(). See tools/testing/selftests/vm/gup_benchmark.c + +config VM_MAX_READAHEAD_KB + int "Default max readahead window size in Kilobytes" + default 128 + help + This sets the VM_MAX_READAHEAD value to allow the readahead window + to grow to a maximum size of configured. Increasing this value will + benefit sequential read throughput. -- 2.16.2.804.g6dcf76e118-goog