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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-02-24 21:01:52 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-24 22:38:27 +0100 |
| commit | 0c7c575df56b957390206deb018c41acbb412159 (patch) | |
| tree | 364372b8c895ce3ff142bf406d4bfb0fde60b582 /mm/filemap.c | |
| parent | mm/filemap: rename generic_file_buffered_read subfunctions (diff) | |
| download | linux-0c7c575df56b957390206deb018c41acbb412159.tar.xz linux-0c7c575df56b957390206deb018c41acbb412159.zip | |
mm/filemap: remove dynamically allocated array from filemap_read
Increasing the batch size runs into diminishing returns. It's probably
better to make, eg, three calls to filemap_get_pages() than it is to call
into kmalloc().
Link: https://lkml.kernel.org/r/20210122160140.223228-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | mm/filemap.c | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index fbfea449f417..f621a7de5833 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2431,8 +2431,8 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, struct file_ra_state *ra = &filp->f_ra; struct address_space *mapping = filp->f_mapping; struct inode *inode = mapping->host; - struct page *pages_onstack[PAGEVEC_SIZE], **pages = NULL; - unsigned int nr_pages = min_t(unsigned int, 512, + struct page *pages[PAGEVEC_SIZE]; + unsigned int nr_pages = min_t(unsigned int, PAGEVEC_SIZE, ((iocb->ki_pos + iter->count + PAGE_SIZE - 1) >> PAGE_SHIFT) - (iocb->ki_pos >> PAGE_SHIFT)); int i, pg_nr, error = 0; @@ -2446,14 +2446,6 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, iov_iter_truncate(iter, inode->i_sb->s_maxbytes); - if (nr_pages > ARRAY_SIZE(pages_onstack)) - pages = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); - - if (!pages) { - pages = pages_onstack; - nr_pages = min_t(unsigned int, nr_pages, ARRAY_SIZE(pages_onstack)); - } - do { cond_resched(); @@ -2538,9 +2530,6 @@ put_pages: file_accessed(filp); - if (pages != pages_onstack) - kfree(pages); - return written ? written : error; } EXPORT_SYMBOL_GPL(generic_file_buffered_read); |