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[159.203.232.101]) by smtp.gmail.com with ESMTPSA id h64sm3254547pfj.40.2019.03.09.21.07.39 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 09 Mar 2019 21:07:43 -0800 (PST) From: Sean Fu X-Google-Original-From: Sean Fu Date: Sun, 10 Mar 2019 13:07:32 +0800 To: "Darrick J. Wong" Cc: Sean Fu , linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] xfs: Use kmem_zalloc for bp->b_pages. Message-ID: <20190310050608.dtidrfuqepze6uoh@linux-xjtn> References: <20190309153636.14154-1-fxinrong@gmail.com> <20190309173230.GA4359@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190309173230.GA4359@magnolia> User-Agent: NeoMutt/20170912 (1.9.0) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 09, 2019 at 09:32:30AM -0800, Darrick J. Wong wrote: > On Sat, Mar 09, 2019 at 11:36:36PM +0800, Sean Fu wrote: > > Change the allocation of bp->b_pages to use kmem_zalloc instead of > > kmem_alloc. > > Remove unnecessary memset for bp->b_pages. > > > > This reduces text size by 42 bytes. > > Before: > > text data bss dec hex filename > > 23335 588 8 23931 5d7b ./fs/xfs/xfs_buf.o > > After: > > text data bss dec hex filename > > 23293 588 8 23889 5d51 ./fs/xfs/xfs_buf.o > > > > Signed-off-by: Sean Fu > > --- > > fs/xfs/xfs_buf.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > > index 4f5f2ff3f70f..be4f740b97c1 100644 > > --- a/fs/xfs/xfs_buf.c > > +++ b/fs/xfs/xfs_buf.c > > @@ -289,12 +289,11 @@ _xfs_buf_get_pages( > > if (page_count <= XB_PAGES) { > > bp->b_pages = bp->b_page_array; > > } else { > > - bp->b_pages = kmem_alloc(sizeof(struct page *) * > > + bp->b_pages = kmem_zalloc(sizeof(struct page *) * > > page_count, KM_NOFS); > > if (bp->b_pages == NULL) > > return -ENOMEM; > > } > > - memset(bp->b_pages, 0, sizeof(struct page *) * page_count); > > Does this leave b_pages uninitialized in the page_count <= XB_PAGES > case? bp is allocated by kmem_zone_zalloc, But i will take a deep look at xfs_buf_associate_memory. > > --D > > > } > > return 0; > > } > > -- > > 2.16.4 > >